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Fullyoung Chang - One of the best experts on this subject based on the ideXlab platform.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused common bile duct ligated rat model of portal hypertension role of nitric oxide and bradykinin
Hepato-gastroenterology, 2009Co-Authors: Chienting Chen, Shwuling Wu, Chechang Chan, Sunsang Wang, Fullyoung Chang, Huichun HuangAbstract:BACKGROUND/AIMS: The portal hypotensive effect of vasopressin during hemorrhage is less effective than that during stable condition in cirrhotic patients or experimental portal hypertension (the so-called hyposensitivity phenomenon). Recent studies have demonstrated that constitutive nitric oxide activities and bradykinin in hemorrhage-transfused partially portal vein-ligated rats are responsible, at least partly, for the splanchnic hyposensitivity to gLypressin (a long acting vasopressin analogue). This study investigated the relative contribution of nitric oxide synthase isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity in rats with cirrhosis induced by common bile duct-ligation (BDL). METHODOLOGY: Five weeks after BDL, systemic and portal hemodynamics were measured in stable or bleeding BDL rats receiving intravenous infusion of gLypressin (0.2 mg/kg). In the treatment groups, N(G)-nitro-L-arginine methyl ester (L-NAME, a non-selective nitric oxide synthase inhibitor), L-canavanine (a specific inducible nitric oxide synthase inhibitor) or HOE 140 (a bradykinin B2 receptor antagonist) was administered 45 minutes before the infusion of gLypressin. In rats with a hypotensive hemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or various inhibitors. RESULTS: Splanchnic hyposensitivity to gLypressin was demonstrated in the hemorrhage-transfused BDL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding BDL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive effects of gLypressin. CONCLUSIONS: Constitutive nitric oxide synthase and bradykinin play major roles in the development of splanchnic hyposensitivity to gLypressin observed in hemorrhage-transfused rats with biliary cirrhosis.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused rat model of portal hypertension the role of tumor necrosis factor α
臺灣消化醫學雜誌, 2007Co-Authors: Huichun Huang, Sunsang Wang, Fullyoung ChangAbstract:Introduction: Vasopressin and its long-acting analogue, gLypressin given during hemorrhage are less effective than when given during a stable state in portal hypertensive or cirrhotic conditions, that is, the so-called hyposensitivity phenomenon. According to the previous studies, nitric oxide has been ascribed to participate in the hyposensitivity. Tumor necrosis factor-α stimulates nitric oxide synthesis and is enhanced during acute hemorrhage. However, its role in portal hypertension with acute hemorrhage and vascular hyporesponsiveness remains unclear. Materials and Methods: Portal hypertension was induced by partial portal vein ligation (PVL) on male Spraque-Dawley rats. Fourteen days after PVL, portal and systemic hemodynamic parameters were evaluated then rats were divided into without-bleeding and with-bleeding groups. In rats with a hypotensive hemorrhage, 4.5ml of blood was withdrawn with an infusion/withdrawal pump, of which 50% was re-infused. The without-bleeding groups received no manipulation during the same period of time. Forty-five minutes later, the second hemodynamic measurement was performed, followed by gLypressin (0.07mg/kg) infusion. Ten minutes after gLypressin administration, the third hemodynamic study was done, followed by heparinized blood sampling for TNF-α measurements. Results: splanchnic hyposensitivity to gLypressin was noted in portal hypetensive rats during acute hemorrhage. The level of tumor necrosis factor tended to be higher in rats with bleeding but not statistically significant (P=0.087). Conclusion: Tumor necrosis factor did not seem to play a significant role in splanchnic hyposensitivity to gLypressin in portal hypertensive rats during acute hemorrhage. The influences of other endogenous vasoactive substances should also be considered.
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nitric oxide synthase expression in the splanchnic hyposensitivity to gLypressin of a hemorrhage transfused rat model with portal hypertension
Journal of The Chinese Medical Association, 2004Co-Authors: Huichun Huang, Chechang Chan, Yichou Chen, Reihwa Lu, Sunsang Wang, Fullyoung Chang, Shwuling WuAbstract:BACKGROUND: Nitric oxide (NO) has been proposed to participate in the vascular hyporesponsiveness to vasopressin and its long-acting analogue gLypressin during hemorrhage in portal hypertensive states. This study surveyed the role of NO regarding splanchnic hyporeactivity to gLypressin and NO synthases (NOS) expression in different vascular beds in bleeding portal-hypertensive rats. METHODS: Under general anesthesia with ketamine, partially portal vein-ligated male Sprague-Dawley rats without or with bleeding were used to investigate the hemodynamic effects of gLypressin (0.07 mg/kg intravenously) and constitutive (cNOS) and inducible NOS (iNOS) mRNA expression over the abdominal aorta and superior mesenteric artery. RESULTS: Splanchnic hyposensitivity to gLypressin was noted in the hemorrhage-transfused rats with enhanced cNOS expression of superior mesenteric artery. No significant differences of cNOS and iNOS expression in abdominal aorta and iNOS in superior mesenteric artery were found between the with-bleeding and without-bleeding groups. CONCLUSIONS: In rats with portal hypertension and acute hemorrhage, cNOS over-expression in superior mesenteric artery may take a part in the splanchnic hyposensitivity to gLypressin.
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cyclooxygenase expression in splanchnic hyposensitivity to gLypressin of bleeding portal hypertensive rats
European Journal of Clinical Investigation, 2003Co-Authors: Choyu Chan, Sunsang Wang, Yungtai Chen, Huichun Huang, Fullyoung Chang, Chengyen ChenAbstract:Background Prostacyclin mediates, at least partly, the splanchnic vascular hyporesponsiveness to gLypressin in bleeding portal hypertensive rats. This study investigated the relative contribution of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in the splanchnic hyposensitivity to gLypressin in rats with portal hypertension induced by partial portal vein ligation (PVL). Methods Fourteen days after the operation, the rats were divided into without- and with-bleeding groups. Three series of PVL rats were used to investigate (i) the haemodynamic effects of gLypressin (0·07 mg kg−1 intravenously), (ii) COX-1/COX-2 mRNA expression over abdominal aorta and superior mesenteric artery and (iii) plasma levels of 6-keto-prostaglandin-F1α. In rats with a hypotensive haemorrhage, 4·5 mL of blood was withdrawn and 50% of the withdrawn blood was re-infused before blood and vessel sampling or the administration of gLypressin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in the haemorrhage-transfused PVL rats with enhanced COX-1 expression of superior mesenteric artery and increased plasma levels of 6-keto-prostaglandin-F1α. There were no differences in the COX-2 expression of superior mesenteric artery and COX-1 and COX-2 expressions of abdominal aorta between without- and with-bleeding groups. Conclusion In portal hypertensive rats with acute haemorrhage, COX-1 over-expression in the superior mesenteric artery plays a role in mediating the splanchnic hyposensitivity to gLypressin.
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inhibition of prostacyclin by indomethacin ameliorates the splanchnic hyposensitivity to gLypressin in haemorrhage transfused common bile duct ligated rats
European Journal of Clinical Investigation, 2001Co-Authors: Sunsang Wang, Choyu Chan, Chengyen Chen, Szuhsien Wu, Fullyoung Chang, Huichun HuangAbstract:Background Prostacyclin (PGI 2 ) is an important contributor to the mediation of hyporeactivity to vasoconstrictors and the development of hyperdynamic circulation in portal hypertensive states. Inhibition of PGI 2 synthesis in haemorrhage-transfused partially portal vein-ligated rats could ameliorate the splanchnic hyposensitivity to gLypressin, a long-acting vasopressin analogue. This study investigated whether the hyposensitivity to gLypressin also exists in rats with common bile duct ligation (BDL) and whether the inhibition of PGI 2 synthesis by indomethacin could potentiate the portal-hypotensive effect of gLypressin in bleeding BDL rats. Methods Two series of BDL rats were used. Series 1 investigated the haemodynamic effects of low dose gLypressin (0.07 mg kg -1 ) in BDL rats with or without bleeding by catheterization. In series 2, haemodynamic parameters were measured in stable or bleeding BDL rats that were receiving intravenously high dose gLypressin (0.2 mg kg -1 ) or indomethacin (5 mg kg -1 ) followed by high dose gLypressin. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or indomethacin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in haemorrhage-transfused BDL rats receiving high, but not low, doses of gLypressin. Indomethacin infusion did not cause significant systemic and portal haemodynamic changes in bleeding BDL rats (P > 0.05). The addition of indomethacin significantly enhanced the portal-hypotensive effects of gLypressin (P < 0.05) and potentiated the increases in mean arterial pressure induced by gLypressin infusion (P < 0.001) in bleeding BDL rats. Conclusion Splanchnic hyposensitivity to gLypressin observed in haemorrhage-transfused BDL rats could be ameliorated by the addition of indomethacin, suggesting a role of endogenous PGI 2 in its pathophysiology.
Sunsang Wang - One of the best experts on this subject based on the ideXlab platform.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused common bile duct ligated rat model of portal hypertension role of nitric oxide and bradykinin
Hepato-gastroenterology, 2009Co-Authors: Chienting Chen, Shwuling Wu, Chechang Chan, Sunsang Wang, Fullyoung Chang, Huichun HuangAbstract:BACKGROUND/AIMS: The portal hypotensive effect of vasopressin during hemorrhage is less effective than that during stable condition in cirrhotic patients or experimental portal hypertension (the so-called hyposensitivity phenomenon). Recent studies have demonstrated that constitutive nitric oxide activities and bradykinin in hemorrhage-transfused partially portal vein-ligated rats are responsible, at least partly, for the splanchnic hyposensitivity to gLypressin (a long acting vasopressin analogue). This study investigated the relative contribution of nitric oxide synthase isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity in rats with cirrhosis induced by common bile duct-ligation (BDL). METHODOLOGY: Five weeks after BDL, systemic and portal hemodynamics were measured in stable or bleeding BDL rats receiving intravenous infusion of gLypressin (0.2 mg/kg). In the treatment groups, N(G)-nitro-L-arginine methyl ester (L-NAME, a non-selective nitric oxide synthase inhibitor), L-canavanine (a specific inducible nitric oxide synthase inhibitor) or HOE 140 (a bradykinin B2 receptor antagonist) was administered 45 minutes before the infusion of gLypressin. In rats with a hypotensive hemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or various inhibitors. RESULTS: Splanchnic hyposensitivity to gLypressin was demonstrated in the hemorrhage-transfused BDL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding BDL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive effects of gLypressin. CONCLUSIONS: Constitutive nitric oxide synthase and bradykinin play major roles in the development of splanchnic hyposensitivity to gLypressin observed in hemorrhage-transfused rats with biliary cirrhosis.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused rat model of portal hypertension the role of tumor necrosis factor α
臺灣消化醫學雜誌, 2007Co-Authors: Huichun Huang, Sunsang Wang, Fullyoung ChangAbstract:Introduction: Vasopressin and its long-acting analogue, gLypressin given during hemorrhage are less effective than when given during a stable state in portal hypertensive or cirrhotic conditions, that is, the so-called hyposensitivity phenomenon. According to the previous studies, nitric oxide has been ascribed to participate in the hyposensitivity. Tumor necrosis factor-α stimulates nitric oxide synthesis and is enhanced during acute hemorrhage. However, its role in portal hypertension with acute hemorrhage and vascular hyporesponsiveness remains unclear. Materials and Methods: Portal hypertension was induced by partial portal vein ligation (PVL) on male Spraque-Dawley rats. Fourteen days after PVL, portal and systemic hemodynamic parameters were evaluated then rats were divided into without-bleeding and with-bleeding groups. In rats with a hypotensive hemorrhage, 4.5ml of blood was withdrawn with an infusion/withdrawal pump, of which 50% was re-infused. The without-bleeding groups received no manipulation during the same period of time. Forty-five minutes later, the second hemodynamic measurement was performed, followed by gLypressin (0.07mg/kg) infusion. Ten minutes after gLypressin administration, the third hemodynamic study was done, followed by heparinized blood sampling for TNF-α measurements. Results: splanchnic hyposensitivity to gLypressin was noted in portal hypetensive rats during acute hemorrhage. The level of tumor necrosis factor tended to be higher in rats with bleeding but not statistically significant (P=0.087). Conclusion: Tumor necrosis factor did not seem to play a significant role in splanchnic hyposensitivity to gLypressin in portal hypertensive rats during acute hemorrhage. The influences of other endogenous vasoactive substances should also be considered.
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nitric oxide synthase expression in the splanchnic hyposensitivity to gLypressin of a hemorrhage transfused rat model with portal hypertension
Journal of The Chinese Medical Association, 2004Co-Authors: Huichun Huang, Chechang Chan, Yichou Chen, Reihwa Lu, Sunsang Wang, Fullyoung Chang, Shwuling WuAbstract:BACKGROUND: Nitric oxide (NO) has been proposed to participate in the vascular hyporesponsiveness to vasopressin and its long-acting analogue gLypressin during hemorrhage in portal hypertensive states. This study surveyed the role of NO regarding splanchnic hyporeactivity to gLypressin and NO synthases (NOS) expression in different vascular beds in bleeding portal-hypertensive rats. METHODS: Under general anesthesia with ketamine, partially portal vein-ligated male Sprague-Dawley rats without or with bleeding were used to investigate the hemodynamic effects of gLypressin (0.07 mg/kg intravenously) and constitutive (cNOS) and inducible NOS (iNOS) mRNA expression over the abdominal aorta and superior mesenteric artery. RESULTS: Splanchnic hyposensitivity to gLypressin was noted in the hemorrhage-transfused rats with enhanced cNOS expression of superior mesenteric artery. No significant differences of cNOS and iNOS expression in abdominal aorta and iNOS in superior mesenteric artery were found between the with-bleeding and without-bleeding groups. CONCLUSIONS: In rats with portal hypertension and acute hemorrhage, cNOS over-expression in superior mesenteric artery may take a part in the splanchnic hyposensitivity to gLypressin.
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cyclooxygenase expression in splanchnic hyposensitivity to gLypressin of bleeding portal hypertensive rats
European Journal of Clinical Investigation, 2003Co-Authors: Choyu Chan, Sunsang Wang, Yungtai Chen, Huichun Huang, Fullyoung Chang, Chengyen ChenAbstract:Background Prostacyclin mediates, at least partly, the splanchnic vascular hyporesponsiveness to gLypressin in bleeding portal hypertensive rats. This study investigated the relative contribution of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in the splanchnic hyposensitivity to gLypressin in rats with portal hypertension induced by partial portal vein ligation (PVL). Methods Fourteen days after the operation, the rats were divided into without- and with-bleeding groups. Three series of PVL rats were used to investigate (i) the haemodynamic effects of gLypressin (0·07 mg kg−1 intravenously), (ii) COX-1/COX-2 mRNA expression over abdominal aorta and superior mesenteric artery and (iii) plasma levels of 6-keto-prostaglandin-F1α. In rats with a hypotensive haemorrhage, 4·5 mL of blood was withdrawn and 50% of the withdrawn blood was re-infused before blood and vessel sampling or the administration of gLypressin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in the haemorrhage-transfused PVL rats with enhanced COX-1 expression of superior mesenteric artery and increased plasma levels of 6-keto-prostaglandin-F1α. There were no differences in the COX-2 expression of superior mesenteric artery and COX-1 and COX-2 expressions of abdominal aorta between without- and with-bleeding groups. Conclusion In portal hypertensive rats with acute haemorrhage, COX-1 over-expression in the superior mesenteric artery plays a role in mediating the splanchnic hyposensitivity to gLypressin.
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inhibition of prostacyclin by indomethacin ameliorates the splanchnic hyposensitivity to gLypressin in haemorrhage transfused common bile duct ligated rats
European Journal of Clinical Investigation, 2001Co-Authors: Sunsang Wang, Choyu Chan, Chengyen Chen, Szuhsien Wu, Fullyoung Chang, Huichun HuangAbstract:Background Prostacyclin (PGI 2 ) is an important contributor to the mediation of hyporeactivity to vasoconstrictors and the development of hyperdynamic circulation in portal hypertensive states. Inhibition of PGI 2 synthesis in haemorrhage-transfused partially portal vein-ligated rats could ameliorate the splanchnic hyposensitivity to gLypressin, a long-acting vasopressin analogue. This study investigated whether the hyposensitivity to gLypressin also exists in rats with common bile duct ligation (BDL) and whether the inhibition of PGI 2 synthesis by indomethacin could potentiate the portal-hypotensive effect of gLypressin in bleeding BDL rats. Methods Two series of BDL rats were used. Series 1 investigated the haemodynamic effects of low dose gLypressin (0.07 mg kg -1 ) in BDL rats with or without bleeding by catheterization. In series 2, haemodynamic parameters were measured in stable or bleeding BDL rats that were receiving intravenously high dose gLypressin (0.2 mg kg -1 ) or indomethacin (5 mg kg -1 ) followed by high dose gLypressin. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or indomethacin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in haemorrhage-transfused BDL rats receiving high, but not low, doses of gLypressin. Indomethacin infusion did not cause significant systemic and portal haemodynamic changes in bleeding BDL rats (P > 0.05). The addition of indomethacin significantly enhanced the portal-hypotensive effects of gLypressin (P < 0.05) and potentiated the increases in mean arterial pressure induced by gLypressin infusion (P < 0.001) in bleeding BDL rats. Conclusion Splanchnic hyposensitivity to gLypressin observed in haemorrhage-transfused BDL rats could be ameliorated by the addition of indomethacin, suggesting a role of endogenous PGI 2 in its pathophysiology.
Chechang Chan - One of the best experts on this subject based on the ideXlab platform.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused common bile duct ligated rat model of portal hypertension role of nitric oxide and bradykinin
Hepato-gastroenterology, 2009Co-Authors: Chienting Chen, Shwuling Wu, Chechang Chan, Sunsang Wang, Fullyoung Chang, Huichun HuangAbstract:BACKGROUND/AIMS: The portal hypotensive effect of vasopressin during hemorrhage is less effective than that during stable condition in cirrhotic patients or experimental portal hypertension (the so-called hyposensitivity phenomenon). Recent studies have demonstrated that constitutive nitric oxide activities and bradykinin in hemorrhage-transfused partially portal vein-ligated rats are responsible, at least partly, for the splanchnic hyposensitivity to gLypressin (a long acting vasopressin analogue). This study investigated the relative contribution of nitric oxide synthase isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity in rats with cirrhosis induced by common bile duct-ligation (BDL). METHODOLOGY: Five weeks after BDL, systemic and portal hemodynamics were measured in stable or bleeding BDL rats receiving intravenous infusion of gLypressin (0.2 mg/kg). In the treatment groups, N(G)-nitro-L-arginine methyl ester (L-NAME, a non-selective nitric oxide synthase inhibitor), L-canavanine (a specific inducible nitric oxide synthase inhibitor) or HOE 140 (a bradykinin B2 receptor antagonist) was administered 45 minutes before the infusion of gLypressin. In rats with a hypotensive hemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or various inhibitors. RESULTS: Splanchnic hyposensitivity to gLypressin was demonstrated in the hemorrhage-transfused BDL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding BDL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive effects of gLypressin. CONCLUSIONS: Constitutive nitric oxide synthase and bradykinin play major roles in the development of splanchnic hyposensitivity to gLypressin observed in hemorrhage-transfused rats with biliary cirrhosis.
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nitric oxide synthase expression in the splanchnic hyposensitivity to gLypressin of a hemorrhage transfused rat model with portal hypertension
Journal of The Chinese Medical Association, 2004Co-Authors: Huichun Huang, Chechang Chan, Yichou Chen, Reihwa Lu, Sunsang Wang, Fullyoung Chang, Shwuling WuAbstract:BACKGROUND: Nitric oxide (NO) has been proposed to participate in the vascular hyporesponsiveness to vasopressin and its long-acting analogue gLypressin during hemorrhage in portal hypertensive states. This study surveyed the role of NO regarding splanchnic hyporeactivity to gLypressin and NO synthases (NOS) expression in different vascular beds in bleeding portal-hypertensive rats. METHODS: Under general anesthesia with ketamine, partially portal vein-ligated male Sprague-Dawley rats without or with bleeding were used to investigate the hemodynamic effects of gLypressin (0.07 mg/kg intravenously) and constitutive (cNOS) and inducible NOS (iNOS) mRNA expression over the abdominal aorta and superior mesenteric artery. RESULTS: Splanchnic hyposensitivity to gLypressin was noted in the hemorrhage-transfused rats with enhanced cNOS expression of superior mesenteric artery. No significant differences of cNOS and iNOS expression in abdominal aorta and iNOS in superior mesenteric artery were found between the with-bleeding and without-bleeding groups. CONCLUSIONS: In rats with portal hypertension and acute hemorrhage, cNOS over-expression in superior mesenteric artery may take a part in the splanchnic hyposensitivity to gLypressin.
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splanchnic hyposensitivity to gLypressin in a haemorrhage transfused rat model of portal hypertension role of nitric oxide and bradykinin
Clinical Science, 2000Co-Authors: W U Shwuling, Sunsang Wang, Fullyoung Chang, Chechang ChanAbstract:Hyposensitivity to vasopressin is a well documented phenomenon in animals with portal hypertension and patients with cirrhosis subject to haemorrhage. Haemorrhage is associated with the endogenous release of bradykinin, which may subsequently stimulate the formation of nitric oxide (NO). The present study investigated the relative contribution of NO synthase (NOS) isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity to a long-acting vasopressin analogue, gLypressin, in rats with portal hypertension induced by partial portal vein ligation (PVL). At 14 days after the operation, systemic and portal haemodynamics were measured in stable or bleeding PVL rats receiving an intravenous infusion of gLypressin (0.07 mg/kg). In the treatment groups, N G -nitro-L-arginine methyl ester (L-NAME; a non-selective NOS inhibitor), L-canavanine (a specific inhibitor of inducible NOS) or HOE 140 (a bradykinin B2 receptor antagonist) was administered 45 min before the infusion of gLypressin. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was re-infused before the administration of gLypressin or various inhibitors. Splanchnic hyposensitivity to gLypressin was demonstrated in the haemorrhage/transfused PVL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding PVL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive eects of gLypressin. It is concluded that constitutive NOS and bradykinin are responsible, at least partly, for the splanchnic hyposensitivity to gLypressin observed in the early stages of the haemorrhage/ transfused rat model of portal hypertension.
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Splanchnic hyposensitivity to gLypressin in a haemorrhage/transfused rat model of portal hypertension: role of nitric oxide and bradykinin.
Clinical Science, 2000Co-Authors: Shwuling Wu, Sunsang Wang, Fullyoung Chang, Chechang ChanAbstract:Hyposensitivity to vasopressin is a well documented phenomenon in animals with portal hypertension and patients with cirrhosis subject to haemorrhage. Haemorrhage is associated with the endogenous release of bradykinin, which may subsequently stimulate the formation of nitric oxide (NO). The present study investigated the relative contribution of NO synthase (NOS) isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity to a long-acting vasopressin analogue, gLypressin, in rats with portal hypertension induced by partial portal vein ligation (PVL). At 14 days after the operation, systemic and portal haemodynamics were measured in stable or bleeding PVL rats receiving an intravenous infusion of gLypressin (0.07 mg/kg). In the treatment groups, N G -nitro-L-arginine methyl ester (L-NAME; a non-selective NOS inhibitor), L-canavanine (a specific inhibitor of inducible NOS) or HOE 140 (a bradykinin B2 receptor antagonist) was administered 45 min before the infusion of gLypressin. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was re-infused before the administration of gLypressin or various inhibitors. Splanchnic hyposensitivity to gLypressin was demonstrated in the haemorrhage/transfused PVL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding PVL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive eects of gLypressin. It is concluded that constitutive NOS and bradykinin are responsible, at least partly, for the splanchnic hyposensitivity to gLypressin observed in the early stages of the haemorrhage/ transfused rat model of portal hypertension.
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aminoguanidine ameliorates splanchnic hyposensitivity to gLypressin in a haemorrhage transfused rat model of portal hypertension
Clinical Science, 1998Co-Authors: Sunsang Wang, W U Shwuling, Fullyoung Chang, Chechang ChanAbstract:Hyposensitivity to vasopressin is a well-documented phenomenon in animals with portal hypertension and patients with cirrhosis subjected to haemorrhage. Excessive formation of nitric oxide is at least partly responsible for the vascular hyporesponsiveness to vasoconstrictors observed in experimental portal hypertension or in rats with haemorrhagic shock. This study investigated whether addition of aminoguanidine, a preferential inducible nitric oxide synthase inhibitor, to gLypressin (a long-acting vasopressin analogue) could enhance its portal hypotensive eect in portal-hypertensive rats with bleeding. 2. Portal hypertension was induced by partial portal vein ligation. Fourteen days after operation, systemic and portal haemodynamics were measured in stable or bleeding portal vein-ligated rats receiving intravenous gLypressin (0.07 mg/kg) or aminoguanidine (70 mg/kg) followed by gLypressin infusion. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or aminoguanidine. 3. GLypressin resulted in a significantly greater decrease in portal pressure in portal vein-ligated rats without bleeding than in those with bleeding (P ! 0.001). In contrast, gLypressin induced similar changes in mean arterial pressure between the two groups (P " 0.05). The addition of aminoguanidine significantly potentiated the portal-hypotensive eect of gLypressin in bleeding portal vein-ligated rats (P ! 0.005) without an eect on the changes in mean arterial pressure induced by gLypressin infusion (P " 0.05).
Huichun Huang - One of the best experts on this subject based on the ideXlab platform.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused common bile duct ligated rat model of portal hypertension role of nitric oxide and bradykinin
Hepato-gastroenterology, 2009Co-Authors: Chienting Chen, Shwuling Wu, Chechang Chan, Sunsang Wang, Fullyoung Chang, Huichun HuangAbstract:BACKGROUND/AIMS: The portal hypotensive effect of vasopressin during hemorrhage is less effective than that during stable condition in cirrhotic patients or experimental portal hypertension (the so-called hyposensitivity phenomenon). Recent studies have demonstrated that constitutive nitric oxide activities and bradykinin in hemorrhage-transfused partially portal vein-ligated rats are responsible, at least partly, for the splanchnic hyposensitivity to gLypressin (a long acting vasopressin analogue). This study investigated the relative contribution of nitric oxide synthase isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity in rats with cirrhosis induced by common bile duct-ligation (BDL). METHODOLOGY: Five weeks after BDL, systemic and portal hemodynamics were measured in stable or bleeding BDL rats receiving intravenous infusion of gLypressin (0.2 mg/kg). In the treatment groups, N(G)-nitro-L-arginine methyl ester (L-NAME, a non-selective nitric oxide synthase inhibitor), L-canavanine (a specific inducible nitric oxide synthase inhibitor) or HOE 140 (a bradykinin B2 receptor antagonist) was administered 45 minutes before the infusion of gLypressin. In rats with a hypotensive hemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or various inhibitors. RESULTS: Splanchnic hyposensitivity to gLypressin was demonstrated in the hemorrhage-transfused BDL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding BDL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive effects of gLypressin. CONCLUSIONS: Constitutive nitric oxide synthase and bradykinin play major roles in the development of splanchnic hyposensitivity to gLypressin observed in hemorrhage-transfused rats with biliary cirrhosis.
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splanchnic hyposensitivity to gLypressin in a hemorrhage transfused rat model of portal hypertension the role of tumor necrosis factor α
臺灣消化醫學雜誌, 2007Co-Authors: Huichun Huang, Sunsang Wang, Fullyoung ChangAbstract:Introduction: Vasopressin and its long-acting analogue, gLypressin given during hemorrhage are less effective than when given during a stable state in portal hypertensive or cirrhotic conditions, that is, the so-called hyposensitivity phenomenon. According to the previous studies, nitric oxide has been ascribed to participate in the hyposensitivity. Tumor necrosis factor-α stimulates nitric oxide synthesis and is enhanced during acute hemorrhage. However, its role in portal hypertension with acute hemorrhage and vascular hyporesponsiveness remains unclear. Materials and Methods: Portal hypertension was induced by partial portal vein ligation (PVL) on male Spraque-Dawley rats. Fourteen days after PVL, portal and systemic hemodynamic parameters were evaluated then rats were divided into without-bleeding and with-bleeding groups. In rats with a hypotensive hemorrhage, 4.5ml of blood was withdrawn with an infusion/withdrawal pump, of which 50% was re-infused. The without-bleeding groups received no manipulation during the same period of time. Forty-five minutes later, the second hemodynamic measurement was performed, followed by gLypressin (0.07mg/kg) infusion. Ten minutes after gLypressin administration, the third hemodynamic study was done, followed by heparinized blood sampling for TNF-α measurements. Results: splanchnic hyposensitivity to gLypressin was noted in portal hypetensive rats during acute hemorrhage. The level of tumor necrosis factor tended to be higher in rats with bleeding but not statistically significant (P=0.087). Conclusion: Tumor necrosis factor did not seem to play a significant role in splanchnic hyposensitivity to gLypressin in portal hypertensive rats during acute hemorrhage. The influences of other endogenous vasoactive substances should also be considered.
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nitric oxide synthase expression in the splanchnic hyposensitivity to gLypressin of a hemorrhage transfused rat model with portal hypertension
Journal of The Chinese Medical Association, 2004Co-Authors: Huichun Huang, Chechang Chan, Yichou Chen, Reihwa Lu, Sunsang Wang, Fullyoung Chang, Shwuling WuAbstract:BACKGROUND: Nitric oxide (NO) has been proposed to participate in the vascular hyporesponsiveness to vasopressin and its long-acting analogue gLypressin during hemorrhage in portal hypertensive states. This study surveyed the role of NO regarding splanchnic hyporeactivity to gLypressin and NO synthases (NOS) expression in different vascular beds in bleeding portal-hypertensive rats. METHODS: Under general anesthesia with ketamine, partially portal vein-ligated male Sprague-Dawley rats without or with bleeding were used to investigate the hemodynamic effects of gLypressin (0.07 mg/kg intravenously) and constitutive (cNOS) and inducible NOS (iNOS) mRNA expression over the abdominal aorta and superior mesenteric artery. RESULTS: Splanchnic hyposensitivity to gLypressin was noted in the hemorrhage-transfused rats with enhanced cNOS expression of superior mesenteric artery. No significant differences of cNOS and iNOS expression in abdominal aorta and iNOS in superior mesenteric artery were found between the with-bleeding and without-bleeding groups. CONCLUSIONS: In rats with portal hypertension and acute hemorrhage, cNOS over-expression in superior mesenteric artery may take a part in the splanchnic hyposensitivity to gLypressin.
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cyclooxygenase expression in splanchnic hyposensitivity to gLypressin of bleeding portal hypertensive rats
European Journal of Clinical Investigation, 2003Co-Authors: Choyu Chan, Sunsang Wang, Yungtai Chen, Huichun Huang, Fullyoung Chang, Chengyen ChenAbstract:Background Prostacyclin mediates, at least partly, the splanchnic vascular hyporesponsiveness to gLypressin in bleeding portal hypertensive rats. This study investigated the relative contribution of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in the splanchnic hyposensitivity to gLypressin in rats with portal hypertension induced by partial portal vein ligation (PVL). Methods Fourteen days after the operation, the rats were divided into without- and with-bleeding groups. Three series of PVL rats were used to investigate (i) the haemodynamic effects of gLypressin (0·07 mg kg−1 intravenously), (ii) COX-1/COX-2 mRNA expression over abdominal aorta and superior mesenteric artery and (iii) plasma levels of 6-keto-prostaglandin-F1α. In rats with a hypotensive haemorrhage, 4·5 mL of blood was withdrawn and 50% of the withdrawn blood was re-infused before blood and vessel sampling or the administration of gLypressin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in the haemorrhage-transfused PVL rats with enhanced COX-1 expression of superior mesenteric artery and increased plasma levels of 6-keto-prostaglandin-F1α. There were no differences in the COX-2 expression of superior mesenteric artery and COX-1 and COX-2 expressions of abdominal aorta between without- and with-bleeding groups. Conclusion In portal hypertensive rats with acute haemorrhage, COX-1 over-expression in the superior mesenteric artery plays a role in mediating the splanchnic hyposensitivity to gLypressin.
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inhibition of prostacyclin by indomethacin ameliorates the splanchnic hyposensitivity to gLypressin in haemorrhage transfused common bile duct ligated rats
European Journal of Clinical Investigation, 2001Co-Authors: Sunsang Wang, Choyu Chan, Chengyen Chen, Szuhsien Wu, Fullyoung Chang, Huichun HuangAbstract:Background Prostacyclin (PGI 2 ) is an important contributor to the mediation of hyporeactivity to vasoconstrictors and the development of hyperdynamic circulation in portal hypertensive states. Inhibition of PGI 2 synthesis in haemorrhage-transfused partially portal vein-ligated rats could ameliorate the splanchnic hyposensitivity to gLypressin, a long-acting vasopressin analogue. This study investigated whether the hyposensitivity to gLypressin also exists in rats with common bile duct ligation (BDL) and whether the inhibition of PGI 2 synthesis by indomethacin could potentiate the portal-hypotensive effect of gLypressin in bleeding BDL rats. Methods Two series of BDL rats were used. Series 1 investigated the haemodynamic effects of low dose gLypressin (0.07 mg kg -1 ) in BDL rats with or without bleeding by catheterization. In series 2, haemodynamic parameters were measured in stable or bleeding BDL rats that were receiving intravenously high dose gLypressin (0.2 mg kg -1 ) or indomethacin (5 mg kg -1 ) followed by high dose gLypressin. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or indomethacin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in haemorrhage-transfused BDL rats receiving high, but not low, doses of gLypressin. Indomethacin infusion did not cause significant systemic and portal haemodynamic changes in bleeding BDL rats (P > 0.05). The addition of indomethacin significantly enhanced the portal-hypotensive effects of gLypressin (P < 0.05) and potentiated the increases in mean arterial pressure induced by gLypressin infusion (P < 0.001) in bleeding BDL rats. Conclusion Splanchnic hyposensitivity to gLypressin observed in haemorrhage-transfused BDL rats could be ameliorated by the addition of indomethacin, suggesting a role of endogenous PGI 2 in its pathophysiology.
Choyu Chan - One of the best experts on this subject based on the ideXlab platform.
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cyclooxygenase expression in splanchnic hyposensitivity to gLypressin of bleeding portal hypertensive rats
European Journal of Clinical Investigation, 2003Co-Authors: Choyu Chan, Sunsang Wang, Yungtai Chen, Huichun Huang, Fullyoung Chang, Chengyen ChenAbstract:Background Prostacyclin mediates, at least partly, the splanchnic vascular hyporesponsiveness to gLypressin in bleeding portal hypertensive rats. This study investigated the relative contribution of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in the splanchnic hyposensitivity to gLypressin in rats with portal hypertension induced by partial portal vein ligation (PVL). Methods Fourteen days after the operation, the rats were divided into without- and with-bleeding groups. Three series of PVL rats were used to investigate (i) the haemodynamic effects of gLypressin (0·07 mg kg−1 intravenously), (ii) COX-1/COX-2 mRNA expression over abdominal aorta and superior mesenteric artery and (iii) plasma levels of 6-keto-prostaglandin-F1α. In rats with a hypotensive haemorrhage, 4·5 mL of blood was withdrawn and 50% of the withdrawn blood was re-infused before blood and vessel sampling or the administration of gLypressin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in the haemorrhage-transfused PVL rats with enhanced COX-1 expression of superior mesenteric artery and increased plasma levels of 6-keto-prostaglandin-F1α. There were no differences in the COX-2 expression of superior mesenteric artery and COX-1 and COX-2 expressions of abdominal aorta between without- and with-bleeding groups. Conclusion In portal hypertensive rats with acute haemorrhage, COX-1 over-expression in the superior mesenteric artery plays a role in mediating the splanchnic hyposensitivity to gLypressin.
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inhibition of prostacyclin by indomethacin ameliorates the splanchnic hyposensitivity to gLypressin in haemorrhage transfused common bile duct ligated rats
European Journal of Clinical Investigation, 2001Co-Authors: Sunsang Wang, Choyu Chan, Chengyen Chen, Szuhsien Wu, Fullyoung Chang, Huichun HuangAbstract:Background Prostacyclin (PGI 2 ) is an important contributor to the mediation of hyporeactivity to vasoconstrictors and the development of hyperdynamic circulation in portal hypertensive states. Inhibition of PGI 2 synthesis in haemorrhage-transfused partially portal vein-ligated rats could ameliorate the splanchnic hyposensitivity to gLypressin, a long-acting vasopressin analogue. This study investigated whether the hyposensitivity to gLypressin also exists in rats with common bile duct ligation (BDL) and whether the inhibition of PGI 2 synthesis by indomethacin could potentiate the portal-hypotensive effect of gLypressin in bleeding BDL rats. Methods Two series of BDL rats were used. Series 1 investigated the haemodynamic effects of low dose gLypressin (0.07 mg kg -1 ) in BDL rats with or without bleeding by catheterization. In series 2, haemodynamic parameters were measured in stable or bleeding BDL rats that were receiving intravenously high dose gLypressin (0.2 mg kg -1 ) or indomethacin (5 mg kg -1 ) followed by high dose gLypressin. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or indomethacin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in haemorrhage-transfused BDL rats receiving high, but not low, doses of gLypressin. Indomethacin infusion did not cause significant systemic and portal haemodynamic changes in bleeding BDL rats (P > 0.05). The addition of indomethacin significantly enhanced the portal-hypotensive effects of gLypressin (P < 0.05) and potentiated the increases in mean arterial pressure induced by gLypressin infusion (P < 0.001) in bleeding BDL rats. Conclusion Splanchnic hyposensitivity to gLypressin observed in haemorrhage-transfused BDL rats could be ameliorated by the addition of indomethacin, suggesting a role of endogenous PGI 2 in its pathophysiology.
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Inhibition of prostacyclin by indomethacin ameliorates the splanchnic hyposensitivity to gLypressin in haemorrhage‐transfused common bile duct‐ligated rats
European Journal of Clinical Investigation, 2001Co-Authors: Sunsang Wang, Choyu Chan, Chun-chia Chen, Szuhsien Wu, Fullyoung Chang, Huichun HuangAbstract:Background Prostacyclin (PGI 2 ) is an important contributor to the mediation of hyporeactivity to vasoconstrictors and the development of hyperdynamic circulation in portal hypertensive states. Inhibition of PGI 2 synthesis in haemorrhage-transfused partially portal vein-ligated rats could ameliorate the splanchnic hyposensitivity to gLypressin, a long-acting vasopressin analogue. This study investigated whether the hyposensitivity to gLypressin also exists in rats with common bile duct ligation (BDL) and whether the inhibition of PGI 2 synthesis by indomethacin could potentiate the portal-hypotensive effect of gLypressin in bleeding BDL rats. Methods Two series of BDL rats were used. Series 1 investigated the haemodynamic effects of low dose gLypressin (0.07 mg kg -1 ) in BDL rats with or without bleeding by catheterization. In series 2, haemodynamic parameters were measured in stable or bleeding BDL rats that were receiving intravenously high dose gLypressin (0.2 mg kg -1 ) or indomethacin (5 mg kg -1 ) followed by high dose gLypressin. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of gLypressin or indomethacin. Results Splanchnic hyposensitivity to gLypressin was demonstrated in haemorrhage-transfused BDL rats receiving high, but not low, doses of gLypressin. Indomethacin infusion did not cause significant systemic and portal haemodynamic changes in bleeding BDL rats (P > 0.05). The addition of indomethacin significantly enhanced the portal-hypotensive effects of gLypressin (P < 0.05) and potentiated the increases in mean arterial pressure induced by gLypressin infusion (P < 0.001) in bleeding BDL rats. Conclusion Splanchnic hyposensitivity to gLypressin observed in haemorrhage-transfused BDL rats could be ameliorated by the addition of indomethacin, suggesting a role of endogenous PGI 2 in its pathophysiology.
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chronic inhibition of nitric oxide ameliorates splanchnic hyposensitivity to gLypressin in a hemorrhage transfused rat model of portal hypertension
Scandinavian Journal of Gastroenterology, 2000Co-Authors: Huichun Huang, Shwuling Wu, Choyu Chan, Sunsang Wang, Fullyoung Chang, C.-t. ChenAbstract:Background: Vasopressin given during hemorrhage is less effective than when given during a stable state in experimental portal hypertension or patients with cirrhosis (the so-called hyposensitivity phenomenon). This study investigated whether chronic inhibition of nitric oxide (NO) synthesis by NG-nitro-L-arginine methyl ester (L-NAME), a non-selective NO synthase inhibitor, could potentiate the portal-hypotensive effect of gLypressin (a long-acting vasopressin analogue) in portal-hypertensive rats during acute bleeding status. Methods: Portal hypertension was induced by partial portal vein ligation (PVL). Rats were divided to receive either L-NAME (~25 mg/kg/day in tap water) or placebo (tap water) treatment orally from 2 days prior to until 14 days after the operation. At the end of treatment, L-NAME-and placebo-treated PVL rats were subdivided into without-bleeding and with-bleeding groups to assess the effects of gLypressin (0.07 mg/kg) on systemic and portal hemodynamics. In rats with a hypotensive h...
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effects of prostacyclin inhibition on splanchnic hyposensitivity to gLypressin in a hemorrhage transfused rat model of portal hypertension
Scandinavian Journal of Gastroenterology, 2000Co-Authors: Sunsang Wang, Shwuling Wu, Choyu Chan, Fullyoung ChangAbstract:Background: Hyposensitivity to vasopressin is a well-documented phenomenon in animals with portal hypertension and patients with cirrhosis and hemorrhage. Similar findings exist with infusion of gLypressin (a long-acting vasopressin analogue), and this phenomenon could be ameliorated by inhibition of nitric oxide (NO) synthase. Besides NO, excessive formation of prostacyclin (PGI2) has been shown to play an important role in the development of hyperdynamic circulation and the mediation of hyporeactivity to vasoconstrictors in portal-hypertensive states. This study was designed to investigate whether the blockade of PGI2 activity by indomethacin infusion could enhance the portal-hypotensive effect of gLypressin in portal-hypertensive rats with bleeding. Methods: Portal hypertension was induced by partial portal vein ligation (PVL). Fourteen days after operation systemic and portal hemodynamics were measured in stable or bleeding PVL rats receiving intravenous gLypressin (0.07 mg/kg) or indomethacin (5 mg/k...
