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John A Rudd - One of the best experts on this subject based on the ideXlab platform.
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use of a microelectrode array to record extracellular pacemaker potentials from the gastrointestinal tracts of the icr mouse and house musk shrew Suncus murinus
Cell Calcium, 2019Co-Authors: Peng Du, W Y Chan, John A RuddAbstract:Abstract Background The rhythmic contraction and relaxation of smooth muscles in the gastrointestinal (GI) tract is governed by pacemaker electrical potentials, also termed slow waves, which are calcium currents generated by interstitial cells of Cajal (ICCs). Malfunction of pacemaker rhythms contributes to a number of clinically challenging gastrointestinal motility disorders. Method A microelectrode array (MEA) was used to record slow waves in vitro from intact GI tissues freshly isolated from the ICR mouse and Suncus murinus . The effects of temperature, extracellular calcium and potassium concentrations on pacemaker potentials were quantified using spatiotemporal metrics. Results Pacemaker frequency decreased from the duodenum to the ileum in the mouse, but this phenomenon was less significant in Suncus murinus . In both the mouse and Suncus murinus , the stomach had a much lower pacemaker frequency than the intestine. Propagation velocity and amplitude were highest in the proximal intestine. Temperature significantly increased pacemaker frequency in the intestinal tissues of both species. Removal of Ca 2+ from the medium inhibited pacemaker potential and increasing the Ca 2+ concentration increased pacemaker frequency in the mouse ileum. Increasing K + concentration decreased pacemaker frequency in the absence of nifedipine. Conclusions The MEA allows efficient investigation of gut pacemaker frequency and propagation.
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involvement of hypothalamic glutamate in cisplatin induced emesis in Suncus murinus house musk shrew
Journal of Pharmacological Sciences, 2009Co-Authors: Kouichi Yamamoto, Sze Wa Chan, John A Rudd, Keiko Asano, Atsushi YamatodaniAbstract:Abstract We investigated the effect of cisplatin on glutamate release in the hypothalamus of Suncus murinus measured by brain microdialysis. Dialysis samples were collected every 20 min for 1 h before and 3 h after the cisplatin (30 mg/kg, i.p.) administration with the animals also being observed for the development of emesis. Cisplatin increased glutamate levels within 1 h and this was closely associated with the occurrence of emesis. Pretreatment with the 5-HT 3 – receptor antagonist ondansetron (2 mg/kg, i.p.) inhibited both the emesis and the increased glutamate levels. These results suggest that hypothalamic glutamate is involved in cisplatin-induced emesis in Suncus murinus .
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Contractile effect of tachykinins on Suncus murinus (house musk shrew) isolated ileum.
Neuropeptides, 2008Co-Authors: Frankie H M Cheng, Sze Wa Chan, John A RuddAbstract:Recent studies used Suncus murinus to investigate the anti-emetic potential of NK(1) tachykinin receptor antagonists. However, the pharmacology of tachykinin receptors in this species has not been fully characterized. In the present studies, therefore, we examined a range of tachykinin receptor agonists for a capacity to induce contractions of the isolated ileum. The tachykinin NK1 receptor preferring agonists substance P, septide and [Sar9Met(O2)11] substance P, and the tachykinin NK2 preferring agonists neurokinin A and GR 64349 (Lys-Asp-Ser-Phe-Val-Gly-R-gamma-lactam-Leu-Met-NH2) caused concentration dependent contractions with EC50 values in the nanomolar range. However, the tachykinin NK3 preferring agonists neurokinin B and senktide (1nM-1microM) induced only weak contractions. The action of senktide, but not [Sar9Met(O2)11] substance P, septide, or GR 64349, was antagonized significantly by atropine (P
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Genital grooming and emesis induced by vanilloids in Suncus murinus, the house musk shrew
European Journal of Pharmacology, 2001Co-Authors: John A RuddAbstract:The potential of resiniferatoxin and capsaicin to modulate emesis and genital grooming was investigated in Suncus murinus. Resinifertoxin (3–30 nmol, i.c.v.), E-capsaicin (10–100 nmol, i.c.v.) and Z-capsaicin (100 nmol, i.c.v.) induced emesis (P 0.05). Only resiniferatoxin induced genital grooming that was antagonised (P 0.05). The emetic action of resiniferatoxin but not E-capsaicin was subject to tachyphylaxis. In cross-tachyphylaxis experiments, E-capsaicin reduced the genital grooming induced by resiniferatoxin (P
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genital grooming and emesis induced by vanilloids in Suncus murinus the house musk shrew
European Journal of Pharmacology, 2001Co-Authors: John A RuddAbstract:The potential of resiniferatoxin and capsaicin to modulate emesis and genital grooming was investigated in Suncus murinus. Resinifertoxin (3–30 nmol, i.c.v.), E-capsaicin (10–100 nmol, i.c.v.) and Z-capsaicin (100 nmol, i.c.v.) induced emesis (P 0.05). Only resiniferatoxin induced genital grooming that was antagonised (P 0.05). The emetic action of resiniferatoxin but not E-capsaicin was subject to tachyphylaxis. In cross-tachyphylaxis experiments, E-capsaicin reduced the genital grooming induced by resiniferatoxin (P<0.05). The data are discussed in relation to the classification of vanilloid receptors and mechanisms involved in emesis and genital grooming.
Norio Matsuki - One of the best experts on this subject based on the ideXlab platform.
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vasopressin induces emesis in Suncus murinus
Japanese Journal of Pharmacology, 2002Co-Authors: Yuji Ikegaya, Norio MatsukiAbstract:Abstract This paper reports that vasopressin is emetogenic in the house musk shrew Suncus murinus. Either intravenous or intracerebroventricular administration of vasopressin caused vomiting within a few minutes. The ED50 of intravenous vasopressin was as high as 4.67 μ g /kg, whereas intracerebroventricularly injected vasopressin was effective at a low dose of 20 ng /brain. The emetogenic target of vasopressin may therefore be present in the central nervous system. We propose the Suncus as a useful animal for investigation of vasopressin-mediated emesis, including motion sickness.
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antiemetic effects of morphine on motion and drug induced emesis in Suncus murinus
Biological & Pharmaceutical Bulletin, 1997Co-Authors: Shuichiro Kakimoto, Hiroshi Saito, Norio MatsukiAbstract:Emetic and antiemetic effects of morphine were investigated in Suncus murinus. Subcutaneous (up to 30 mg/kg) or intracerebroventricular administration (50 μg) of morphine failed to cause emesis. However, pretreatment with morphine (s.c.) prevented the emesis induced by nicotine (10 mg/kg, i.p.), copper sulfate (40 mg/kg, p.o.), cisplatin(20 mg/kg, i.p.) and motion stimulus. These results suggest that morphine has only antiemetic potency and may block a common mechanism for the emetic reflex of Suncus, because the antiemetic effects of the drug were exerted irrespective of the stimulus.
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Involvement of a peripheral mechanism in the emesis induced by cardiac glycosides in Suncus murinus
Biological & Pharmaceutical Bulletin, 1997Co-Authors: Shuichiro Kakimoto, Hiroshi Saito, Norio MatsukiAbstract:The ability of three cardiac glycosides, ouabain, digitonin and digitoxin, to induce emesis and their mechanism(s) of action were investigated in Suncus murinus. The intraperitoneal injection of ouabain but not digitonin nor digitoxin caused vomiting in a dose-dependent manner. However, the administration of ouabain into the cerebroventricle did not cause emesis. Ouabain-induced emesis was partly prevented by surgical abdominal vagotomy. Pretreatment with tropisetron, a selective 5-HT 3 (5-hydroxytriptamine) receptor antagonist, did not affect the emetic response evoked by ouabain. These results suggest that ouabain exerts emetic effects via peripheral mechanism(s), but 5-HT 3 receptors are not involved in the pathway.
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Prophylactic effect of serotonin uptake inhibitors against motion sickness in Suncus murinus
European Journal of Pharmacology, 1996Co-Authors: Fumihiko Okada, Hiroshi Saito, Norio MatsukiAbstract:The prophylactic effect of serotonin uptake inhibitors, imipramine and fluoxetine, against motion sickness was investigated in Suncus murinus. Imipramine (s.c.) and fluoxetine (i.p.) inhibited motion-induced emesis dose dependently with ID50 values of 1.7 and 26 mg/kg, respectively. The results suggest that increasing the concentration of serotonin in the synaptic cleft can prevent motion-induced emesis and that serotonin uptake inhibitors are effective as anti-motion sickness drugs.
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antiemetic effects of serotonergic 5 ht1a receptor agonists in Suncus murinus
Japanese Journal of Pharmacology, 1994Co-Authors: Fumihiko Okada, Hiroshi Saito, Yoshifumi Torii, Norio MatsukiAbstract:The antiemetic effects of six serotonergic 5-HT1A-receptor agonists, 8-hydroxy-2-(di-n-propylamino)tetrarin (8-OH-DPAT), 4-{4-[4-(2-pyrimidinyl)piperazin-l-yl]butyl}-2, 3, 4, 5-tetrahydro-l, 4-benzo-xazepine-3, 5-dione (SUN8399), buspirone, gepirone, ipsapirone and tandospirone, against motion sickness were investigated in Suncus murinus. Subcutaneous injection of all six agonists completely and dose-dependently suppressed motion-induced emesis. Pretreatment with 8-OH-DPAT or SUN8399 dose-dependently inhibited emesis elicited by nicotine (4.0 mg/kg, s.c.), veratrine (0.7 mg/kg, s.c.), cisplatin (20 mg/kg, i.p.) and copper sulfate (40 mg/kg, p.o.). These results suggest that serotonergic 5-HT1A-receptor agonists are effective as anti-motion sickness drugs, and these drugs may block a common mechanism(s) for the emetic reflex of the Suncus because the antiemetic effects of the 5-HT1A-receptor agonists were exerted irrespective of the stimulus.
Hiroshi Saito - One of the best experts on this subject based on the ideXlab platform.
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antiemetic effects of morphine on motion and drug induced emesis in Suncus murinus
Biological & Pharmaceutical Bulletin, 1997Co-Authors: Shuichiro Kakimoto, Hiroshi Saito, Norio MatsukiAbstract:Emetic and antiemetic effects of morphine were investigated in Suncus murinus. Subcutaneous (up to 30 mg/kg) or intracerebroventricular administration (50 μg) of morphine failed to cause emesis. However, pretreatment with morphine (s.c.) prevented the emesis induced by nicotine (10 mg/kg, i.p.), copper sulfate (40 mg/kg, p.o.), cisplatin(20 mg/kg, i.p.) and motion stimulus. These results suggest that morphine has only antiemetic potency and may block a common mechanism for the emetic reflex of Suncus, because the antiemetic effects of the drug were exerted irrespective of the stimulus.
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Involvement of a peripheral mechanism in the emesis induced by cardiac glycosides in Suncus murinus
Biological & Pharmaceutical Bulletin, 1997Co-Authors: Shuichiro Kakimoto, Hiroshi Saito, Norio MatsukiAbstract:The ability of three cardiac glycosides, ouabain, digitonin and digitoxin, to induce emesis and their mechanism(s) of action were investigated in Suncus murinus. The intraperitoneal injection of ouabain but not digitonin nor digitoxin caused vomiting in a dose-dependent manner. However, the administration of ouabain into the cerebroventricle did not cause emesis. Ouabain-induced emesis was partly prevented by surgical abdominal vagotomy. Pretreatment with tropisetron, a selective 5-HT 3 (5-hydroxytriptamine) receptor antagonist, did not affect the emetic response evoked by ouabain. These results suggest that ouabain exerts emetic effects via peripheral mechanism(s), but 5-HT 3 receptors are not involved in the pathway.
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Prophylactic effect of serotonin uptake inhibitors against motion sickness in Suncus murinus
European Journal of Pharmacology, 1996Co-Authors: Fumihiko Okada, Hiroshi Saito, Norio MatsukiAbstract:The prophylactic effect of serotonin uptake inhibitors, imipramine and fluoxetine, against motion sickness was investigated in Suncus murinus. Imipramine (s.c.) and fluoxetine (i.p.) inhibited motion-induced emesis dose dependently with ID50 values of 1.7 and 26 mg/kg, respectively. The results suggest that increasing the concentration of serotonin in the synaptic cleft can prevent motion-induced emesis and that serotonin uptake inhibitors are effective as anti-motion sickness drugs.
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antiemetic effects of serotonergic 5 ht1a receptor agonists in Suncus murinus
Japanese Journal of Pharmacology, 1994Co-Authors: Fumihiko Okada, Hiroshi Saito, Yoshifumi Torii, Norio MatsukiAbstract:The antiemetic effects of six serotonergic 5-HT1A-receptor agonists, 8-hydroxy-2-(di-n-propylamino)tetrarin (8-OH-DPAT), 4-{4-[4-(2-pyrimidinyl)piperazin-l-yl]butyl}-2, 3, 4, 5-tetrahydro-l, 4-benzo-xazepine-3, 5-dione (SUN8399), buspirone, gepirone, ipsapirone and tandospirone, against motion sickness were investigated in Suncus murinus. Subcutaneous injection of all six agonists completely and dose-dependently suppressed motion-induced emesis. Pretreatment with 8-OH-DPAT or SUN8399 dose-dependently inhibited emesis elicited by nicotine (4.0 mg/kg, s.c.), veratrine (0.7 mg/kg, s.c.), cisplatin (20 mg/kg, i.p.) and copper sulfate (40 mg/kg, p.o.). These results suggest that serotonergic 5-HT1A-receptor agonists are effective as anti-motion sickness drugs, and these drugs may block a common mechanism(s) for the emetic reflex of the Suncus because the antiemetic effects of the 5-HT1A-receptor agonists were exerted irrespective of the stimulus.
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Role of histamine in motion sickness in Suncus murinus.
Aviation Space and Environmental Medicine, 1991Co-Authors: Kaji T, Shinya Ueno, Hiroshi Saito, Yasuhara T, Nakajima T, Matsuki NAbstract:The levels of histamine (HA) and tele-methylhistamine (t-MH) were determined in five brain regions of Suncus murinus (Suncus) and the effects of motion stimulus or drugs influencing the turnover of these amines were studied to elucidate the role of histamine in motion sickness. Shaking the animals for 2 min increased HA contents in telencephalon and diencephalon without significantly changing the t-MH levels. alpha-Fluoromethylhistidine (alpha-FMH), which is presumed to deplete the neuronal HA, tended to raise the HA levels. alpha-FMH slightly alleviated the vomiting response to motion stimulus and suppressed the HA increase in diencephalon caused by shaking. Compound 48/80, which releases HA from mast cells, did not alter the control HA levels, but effectively prevented the motion sickness and completely suppressed the motion-induced rises in HA levels. These results provide further evidence that brain HA plays an important role in the development of motion sickness.
Dongliang Hu - One of the best experts on this subject based on the ideXlab platform.
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induction of emetic response to staphylococcal enterotoxins in the house musk shrew Suncus murinus
Infection and Immunity, 2003Co-Authors: Dongliang Hu, Katsuhiko Omoe, Yu Shimoda, Akio Nakane, Kunihiro ShinagawaAbstract:The emetic responses induced by staphylococcal enterotoxin A (SEA), SEB, SEC2, SED, SEE, SEG, SEH, and SEI in the house musk shrew (Suncus murinus) were investigated. SEA, SEE, and SEI showed higher emetic activity in the house musk shrew than the other SEs. SEB, SEC2, SED, SEG, and SEH also induced emetic responses in this animal model but relatively high doses were required. The house musk shrew appears to be a valuable model for studying the mechanisms of emetic reactions caused by SEs.
Kunihiro Shinagawa - One of the best experts on this subject based on the ideXlab platform.
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induction of emetic response to staphylococcal enterotoxins in the house musk shrew Suncus murinus
Infection and Immunity, 2003Co-Authors: Dongliang Hu, Katsuhiko Omoe, Yu Shimoda, Akio Nakane, Kunihiro ShinagawaAbstract:The emetic responses induced by staphylococcal enterotoxin A (SEA), SEB, SEC2, SED, SEE, SEG, SEH, and SEI in the house musk shrew (Suncus murinus) were investigated. SEA, SEE, and SEI showed higher emetic activity in the house musk shrew than the other SEs. SEB, SEC2, SED, SEG, and SEH also induced emetic responses in this animal model but relatively high doses were required. The house musk shrew appears to be a valuable model for studying the mechanisms of emetic reactions caused by SEs.
