The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform
Enri Borda - One of the best experts on this subject based on the ideXlab platform.
-
Endogenous signalling system involved in parotid gland adenosine A1 receptor‐Amylase Release
Acta physiologica (Oxford England), 2006Co-Authors: A. Finkelberg, Lucila Busch, Silvia Reina, Leonor Sterin-borda, Enri BordaAbstract:Aim: In this study, we have determined signalling pathways involved in adenosine A1 receptor (A1 receptor)-dependent stimulation of Amylase Release in rat parotid gland. Methods: Amylase Release, binding and cyclic adenosine monophosphate (cAMP) assays, inositol phosphates (IPs) production and nitric oxide synthase (NOS) activity in the presence of cyclopentyl-1,3-dipropylxanthine (CPA) alone or in the presence of different inhibitory drugs were performed. Results: The binding parameters of specific A1 antagonist [3H]-cyclopentyl 1,3-dipropilxanthine ([3H]-DPCPX) in parotid gland membranes show a population of high affinity sites with Kd (nm) 0.53 ± 0.06 and Bmax (fmol mg−1 protein) 122.6 ± 10.2. CPA stimulation of A1 receptor exerts an increase in Amylase Release, IPs accumulation, cAMP production and NOS activity. All these A1 agonist effects were blocked by the A1 receptor antagonist DPCPX. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), protein kinase C (PKC), and adenylate cyclase, but not NOS, activities attenuated the CPA stimulatory effect on Amylase Release. The effect of CPA on Amylase Release significantly correlated with its action either on cAMP or on IPs accumulation. Conclusion: These results suggest that CPA activation of parotid gland A1 receptor induces a stimulatory effect on Amylase Release associated with increased production of cAMP and IPs accumulation. The mechanism appears to occur secondarily to stimulation of phosphoinositide turnover via PLC activation. This, in turn, triggers cascade reactions involving CaM and PKC. The CPA stimulation of NOS does not appear to participate in Amylase Release.
-
endogenous signalling system involved in parotid gland adenosine a1 receptor Amylase Release
Acta Physiologica, 2006Co-Authors: A. Finkelberg, Lucila Busch, Silvia Reina, Enri Borda, Leonor SterinbordaAbstract:Aim: In this study, we have determined signalling pathways involved in adenosine A1 receptor (A1 receptor)-dependent stimulation of Amylase Release in rat parotid gland. Methods: Amylase Release, binding and cyclic adenosine monophosphate (cAMP) assays, inositol phosphates (IPs) production and nitric oxide synthase (NOS) activity in the presence of cyclopentyl-1,3-dipropylxanthine (CPA) alone or in the presence of different inhibitory drugs were performed. Results: The binding parameters of specific A1 antagonist [3H]-cyclopentyl 1,3-dipropilxanthine ([3H]-DPCPX) in parotid gland membranes show a population of high affinity sites with Kd (nm) 0.53 ± 0.06 and Bmax (fmol mg−1 protein) 122.6 ± 10.2. CPA stimulation of A1 receptor exerts an increase in Amylase Release, IPs accumulation, cAMP production and NOS activity. All these A1 agonist effects were blocked by the A1 receptor antagonist DPCPX. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), protein kinase C (PKC), and adenylate cyclase, but not NOS, activities attenuated the CPA stimulatory effect on Amylase Release. The effect of CPA on Amylase Release significantly correlated with its action either on cAMP or on IPs accumulation. Conclusion: These results suggest that CPA activation of parotid gland A1 receptor induces a stimulatory effect on Amylase Release associated with increased production of cAMP and IPs accumulation. The mechanism appears to occur secondarily to stimulation of phosphoinositide turnover via PLC activation. This, in turn, triggers cascade reactions involving CaM and PKC. The CPA stimulation of NOS does not appear to participate in Amylase Release.
-
Castration decreases Amylase Release associated with muscarinic acetylcholine receptor downregulation in rat parotid gland.
British journal of pharmacology, 2003Co-Authors: Lucila Busch, Enri BordaAbstract:The mechanism and receptor subtypes involved in carbachol-stimulated Amylase Release and its changes after castration were studied in parotid slices from male rats. Carbachol induced both Amylase Release and inositol phosphate (IP) accumulation in parotid slices from control and castrated rats, but castration induced a decrease of carbachol maximal effect. The effect of castration was reverted by testosterone replacement. The selective M1 and M3 muscarinic receptor antagonists, pirenzepine and 4-diphenylacetoxy-N-methylpiperidine methiodide, respectively, inhibited carbachol-stimulated Amylase Release and IP accumulation in a dose-dependent manner in parotid slices from control and castrated rats. A diminution of binding sites of muscarinic receptor in parotid membrane from castrated rats was observed. Competition binding assays showed that both, M1 and M3 muscarinic receptor subtypes are expressed in membranes of parotid glands from control and castrated rats, M3 being the greater population. These results suggest that Amylase Release induced by carbachol in parotid slices is mediated by phosphoinositide accumulation. This mechanism appears to be triggered by the activation of M1 and M3 muscarinic receptor subtypes. Castration induced a decrease of the maximal effect of carbachol evoked Amylase Release and IP accumulation followed by a diminution in the number of parotid gland muscarinic acetylcholine receptors. British Journal of Pharmacology (2003) 139, 399–407. doi:10.1038/sj.bjp.0705260
-
influence of castration on isoprenaline induced Amylase Release in parotid gland from male rats
Experimental Physiology, 2002Co-Authors: Lucila Busch, Enri BordaAbstract:The purpose of this study was to determine the influence of testosterone, the male sex hormone, on beta-adrenergic agonist-induced Amylase secretion from rat parotid glands. Isoprenaline (isoproterenol)-induced Amylase secretion was measured in vitro from the parotid glands of control and castrated rats with and without testosterone replacement. The isoprenaline-induced Amylase Release was reduced in parotid glands from castrated rats compared to controls. The reduction of Amylase Release by isoprenaline in parotid glands of castrated rats, could be reversed by administration of testosterone. Furthermore, beta-adrenergic receptor density and the level of isoprenaline-evoked cAMP in parotid glands from castrated rats was lower compared to intact rats. Using SQ-22536 (an adenylyl cyclase inhibitor), dibutyryl cAMP (a cAMP analogue) and verapamil (a calcium channel blocker), we conclude that the impairment of Amylase Release from parotid glands after castration was not related to either adenylyl cyclase activity or cAMP accumulation. Amylase Release from the parotid glands of castrated rats appears to be mediated by an increase in calcium ion influx.
-
Differences in the regulatory mechanism of Amylase Release by rat parotid and submandibular glands.
Archives of oral biology, 2002Co-Authors: Lucila Busch, Leonor Sterin-borda, Enri BordaAbstract:Abstract It is not known whether the mechanisms involved in Amylase Release in submandibular and parotid glands are similar. Here, the participation of different signalling pathways in Amylase Release by the parotid and submandibular glands of the male rat was compared by studying the secretory response after β-adrenergic stimulation. The β-adrenergic agonist isoproterenol induced an increase of cAMP in both salivary glands, but while in the parotid it triggered Amylase Release, in the submandibular it was unable to increase Amylase secretion. Parotid Amylase Release was dependent on adenylate cyclase activation, as SQ-22536 inhibited the secretory effect. In contrast, submandibular Amylase secretion did not depend on the intracellular concentration of cAMP, as SQ-22536 did not modify its secretory response. Moreover, other activators of adenylate cyclase, such as forskolin and prostaglandin E 2 , also failed to modify Amylase Release by the submandibular gland. Neither ionophores nor calcium-blocking agents, as well as calcium–calmodulin and nitric oxide synthase inhibitors, were effective in modifying basal Amylase Release by the submandibular gland. However, the disruption of microfilaments with cytochalasin B, but not the disruption of microtubules with colchicine, prevented Amylase Release in that gland. It is concluded that Amylase exocytosis in the submandibular gland is a constitutive non-regulated phenomenon, as it is independent of extracellular or intracellular signals. It depends only on the integrity of the microfilaments, probably used by the vesicles to travel from the Golgi apparatus to the plasma membrane.
Lucila Busch - One of the best experts on this subject based on the ideXlab platform.
-
Endogenous signalling system involved in parotid gland adenosine A1 receptor‐Amylase Release
Acta physiologica (Oxford England), 2006Co-Authors: A. Finkelberg, Lucila Busch, Silvia Reina, Leonor Sterin-borda, Enri BordaAbstract:Aim: In this study, we have determined signalling pathways involved in adenosine A1 receptor (A1 receptor)-dependent stimulation of Amylase Release in rat parotid gland. Methods: Amylase Release, binding and cyclic adenosine monophosphate (cAMP) assays, inositol phosphates (IPs) production and nitric oxide synthase (NOS) activity in the presence of cyclopentyl-1,3-dipropylxanthine (CPA) alone or in the presence of different inhibitory drugs were performed. Results: The binding parameters of specific A1 antagonist [3H]-cyclopentyl 1,3-dipropilxanthine ([3H]-DPCPX) in parotid gland membranes show a population of high affinity sites with Kd (nm) 0.53 ± 0.06 and Bmax (fmol mg−1 protein) 122.6 ± 10.2. CPA stimulation of A1 receptor exerts an increase in Amylase Release, IPs accumulation, cAMP production and NOS activity. All these A1 agonist effects were blocked by the A1 receptor antagonist DPCPX. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), protein kinase C (PKC), and adenylate cyclase, but not NOS, activities attenuated the CPA stimulatory effect on Amylase Release. The effect of CPA on Amylase Release significantly correlated with its action either on cAMP or on IPs accumulation. Conclusion: These results suggest that CPA activation of parotid gland A1 receptor induces a stimulatory effect on Amylase Release associated with increased production of cAMP and IPs accumulation. The mechanism appears to occur secondarily to stimulation of phosphoinositide turnover via PLC activation. This, in turn, triggers cascade reactions involving CaM and PKC. The CPA stimulation of NOS does not appear to participate in Amylase Release.
-
endogenous signalling system involved in parotid gland adenosine a1 receptor Amylase Release
Acta Physiologica, 2006Co-Authors: A. Finkelberg, Lucila Busch, Silvia Reina, Enri Borda, Leonor SterinbordaAbstract:Aim: In this study, we have determined signalling pathways involved in adenosine A1 receptor (A1 receptor)-dependent stimulation of Amylase Release in rat parotid gland. Methods: Amylase Release, binding and cyclic adenosine monophosphate (cAMP) assays, inositol phosphates (IPs) production and nitric oxide synthase (NOS) activity in the presence of cyclopentyl-1,3-dipropylxanthine (CPA) alone or in the presence of different inhibitory drugs were performed. Results: The binding parameters of specific A1 antagonist [3H]-cyclopentyl 1,3-dipropilxanthine ([3H]-DPCPX) in parotid gland membranes show a population of high affinity sites with Kd (nm) 0.53 ± 0.06 and Bmax (fmol mg−1 protein) 122.6 ± 10.2. CPA stimulation of A1 receptor exerts an increase in Amylase Release, IPs accumulation, cAMP production and NOS activity. All these A1 agonist effects were blocked by the A1 receptor antagonist DPCPX. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), protein kinase C (PKC), and adenylate cyclase, but not NOS, activities attenuated the CPA stimulatory effect on Amylase Release. The effect of CPA on Amylase Release significantly correlated with its action either on cAMP or on IPs accumulation. Conclusion: These results suggest that CPA activation of parotid gland A1 receptor induces a stimulatory effect on Amylase Release associated with increased production of cAMP and IPs accumulation. The mechanism appears to occur secondarily to stimulation of phosphoinositide turnover via PLC activation. This, in turn, triggers cascade reactions involving CaM and PKC. The CPA stimulation of NOS does not appear to participate in Amylase Release.
-
Castration decreases Amylase Release associated with muscarinic acetylcholine receptor downregulation in rat parotid gland.
British journal of pharmacology, 2003Co-Authors: Lucila Busch, Enri BordaAbstract:The mechanism and receptor subtypes involved in carbachol-stimulated Amylase Release and its changes after castration were studied in parotid slices from male rats. Carbachol induced both Amylase Release and inositol phosphate (IP) accumulation in parotid slices from control and castrated rats, but castration induced a decrease of carbachol maximal effect. The effect of castration was reverted by testosterone replacement. The selective M1 and M3 muscarinic receptor antagonists, pirenzepine and 4-diphenylacetoxy-N-methylpiperidine methiodide, respectively, inhibited carbachol-stimulated Amylase Release and IP accumulation in a dose-dependent manner in parotid slices from control and castrated rats. A diminution of binding sites of muscarinic receptor in parotid membrane from castrated rats was observed. Competition binding assays showed that both, M1 and M3 muscarinic receptor subtypes are expressed in membranes of parotid glands from control and castrated rats, M3 being the greater population. These results suggest that Amylase Release induced by carbachol in parotid slices is mediated by phosphoinositide accumulation. This mechanism appears to be triggered by the activation of M1 and M3 muscarinic receptor subtypes. Castration induced a decrease of the maximal effect of carbachol evoked Amylase Release and IP accumulation followed by a diminution in the number of parotid gland muscarinic acetylcholine receptors. British Journal of Pharmacology (2003) 139, 399–407. doi:10.1038/sj.bjp.0705260
-
influence of castration on isoprenaline induced Amylase Release in parotid gland from male rats
Experimental Physiology, 2002Co-Authors: Lucila Busch, Enri BordaAbstract:The purpose of this study was to determine the influence of testosterone, the male sex hormone, on beta-adrenergic agonist-induced Amylase secretion from rat parotid glands. Isoprenaline (isoproterenol)-induced Amylase secretion was measured in vitro from the parotid glands of control and castrated rats with and without testosterone replacement. The isoprenaline-induced Amylase Release was reduced in parotid glands from castrated rats compared to controls. The reduction of Amylase Release by isoprenaline in parotid glands of castrated rats, could be reversed by administration of testosterone. Furthermore, beta-adrenergic receptor density and the level of isoprenaline-evoked cAMP in parotid glands from castrated rats was lower compared to intact rats. Using SQ-22536 (an adenylyl cyclase inhibitor), dibutyryl cAMP (a cAMP analogue) and verapamil (a calcium channel blocker), we conclude that the impairment of Amylase Release from parotid glands after castration was not related to either adenylyl cyclase activity or cAMP accumulation. Amylase Release from the parotid glands of castrated rats appears to be mediated by an increase in calcium ion influx.
-
Differences in the regulatory mechanism of Amylase Release by rat parotid and submandibular glands.
Archives of oral biology, 2002Co-Authors: Lucila Busch, Leonor Sterin-borda, Enri BordaAbstract:Abstract It is not known whether the mechanisms involved in Amylase Release in submandibular and parotid glands are similar. Here, the participation of different signalling pathways in Amylase Release by the parotid and submandibular glands of the male rat was compared by studying the secretory response after β-adrenergic stimulation. The β-adrenergic agonist isoproterenol induced an increase of cAMP in both salivary glands, but while in the parotid it triggered Amylase Release, in the submandibular it was unable to increase Amylase secretion. Parotid Amylase Release was dependent on adenylate cyclase activation, as SQ-22536 inhibited the secretory effect. In contrast, submandibular Amylase secretion did not depend on the intracellular concentration of cAMP, as SQ-22536 did not modify its secretory response. Moreover, other activators of adenylate cyclase, such as forskolin and prostaglandin E 2 , also failed to modify Amylase Release by the submandibular gland. Neither ionophores nor calcium-blocking agents, as well as calcium–calmodulin and nitric oxide synthase inhibitors, were effective in modifying basal Amylase Release by the submandibular gland. However, the disruption of microfilaments with cytochalasin B, but not the disruption of microtubules with colchicine, prevented Amylase Release in that gland. It is concluded that Amylase exocytosis in the submandibular gland is a constitutive non-regulated phenomenon, as it is independent of extracellular or intracellular signals. It depends only on the integrity of the microfilaments, probably used by the vesicles to travel from the Golgi apparatus to the plasma membrane.
Michael W. Mulholland - One of the best experts on this subject based on the ideXlab platform.
-
Gastrin-releasing peptide stimulation of Amylase Release from rat pancreatic lobules involves intrapancreatic neurons.
Pancreas, 1994Co-Authors: Kenneth M. Flowe, Theodore H. Welling, Michael W. MulhollandAbstract:Gastrin releasing peptide (GRP) immunoreactivity has been localized to nerve fibers innervating pancreatic acini and identified in nerve cell bodies within intrapancreatic ganglia. The role of intrapancreatic neurotransmission in GRP- and neuromedin C (NmC)-stimulated Amylase Release was investigated using rat pancreatic lobules in vitro. Lobule responsiveness to neuronal depolarization was demonstrated by Amylase Release upon exposure to 55 mM potassium (207 +/- 7% of control) or veratridine (294 +/- 12%). Both GRP and NmC produced dose-dependent increases in lobular Amylase Release, with ED50 values of 1.1 nM and 0.13 nM, respectively. Amylase Release in response to submaximal concentrations of GRP were significantly inhibited by tetrodotoxin (78 +/- 5% of control) or hexamethonium (71 +/- 5% of control). GRP-stimulated Amylase Release was decreased to 71 +/- 5% of control by atropine coincubation. NmC-stimulated Amylase Release was not affected by tetrodotoxin, hexamethonium, or atropine. GRP (10(-10) to 10(-6) M) produced dose-dependent increments in [3H]acetylcholine Release from pancreatic lobules. GRP stimulates Amylase Release from rat pancreatic lobules by a neurally mediated mechanism in addition to direct action on acinar membrane receptors.
-
galanin inhibits rat pancreatic Amylase Release via cholinergic suppression
Peptides, 1992Co-Authors: Kenneth M. Flowe, Kathleen M Lally, Michael W. MulhollandAbstract:Abstract The effects of galanin on pancreatic exocrine function were examined using rat pancreatic tissues. In anesthetized rats, galanin (40 μg/kg/h) decreased Amylase secretion stimulated by 2-deoxy glucose ( 5.8 ± 0.1 vs. 3.1 ± 0.1 times basal) and cholecystokinin octapeptide ( 21.5 ± 0.6 vs. 16.8 ± 0.5 ), while not inhibiting bethanechol-stimulated secretion. In dispersed acini, there was no effect of galanin alone (10−8 to 10−13 M) on Amylase Release, nor did galanin (10−6 or 10−8 M) coincubation affect Amylase Release stimulated by bethanechol (10−3 to 10−7 M) or CCK-8 (10−8 to 10−13 M). Using pancreatic lobules, coincubation with galanin (10−6 M) suppressed 75 mM KCl-stimulated Amylase secretion and ACh Release ( 10.1 ± 0.6% vs. 7.3 ± 0.4% ). Veratridine-stimulated (10−4 M) Amylase secretion and ACh Release ( 12.4 ± 1.7% vs. 8.5 ± 0.7% ) were similarly diminished.
Keitaro Satoh - One of the best experts on this subject based on the ideXlab platform.
-
MARCKS phosphorylation and Amylase Release in GLP-1-stimulated acini isolated from rat pancreas
The Journal of Physiological Sciences, 2019Co-Authors: Keitaro Satoh, Motoshi Ouchi, Asuka Morita, Masanori KashimataAbstract:Little is known about the effects of glucagon-like peptide 1 (GLP-1) on the pancreatic exocrine gland. In the gland, secretagogues induce Amylase Release. That signal transduction is evoked mainly by an increase in intracellular Ca^2+ levels and activation of protein kinase C (PKC). We previously demonstrated that myristoylated alanine-rich C kinase substrate (MARCKS), a PKC substrate, is involved in pancreatic Amylase Release. Here, we studied the effects of GLP-1 on MARCKS phosphorylation and Amylase Release in rat pancreatic acini. GLP-1 induced Amylase Release and MARCKS phosphorylation in isolated pancreatic acini. Inhibitors of cAMP-dependent protein kinase (PKA) suppressed those effects. Furthermore, a MARCKS-related peptide inhibited the GLP-1-induced Amylase Release. These findings suggest that GLP-1 induces Amylase Release through MARCKS phosphorylation via activation of PKA in isolated pancreatic acini.
-
Involvement of myristoylated alanine-rich C kinase substrate phosphorylation and translocation in cholecystokinin-induced Amylase Release in rat pancreatic acini
American journal of physiology. Gastrointestinal and liver physiology, 2016Co-Authors: Keitaro Satoh, Hiroshi Sugiya, Takanori Narita, Osamu Katsumata-kato, Yoshiteru SeoAbstract:Cholecystokinin (CCK) is a gastrointestinal hormone that induces exocytotic Amylase Release in pancreatic acinar cells. The activation of protein kinase C (PKC) is involved in the CCK-induced pancreatic Amylase Release. Myristoylated alanine-rich C kinase substrate (MARCKS) is a ubiquitously expressed substrate of PKC. MARCKS has been implicated in membrane trafficking in several cell types. The phosphorylation of MARCKS by PKC results in the translocation of MARCKS from the membrane to the cytosol. Here, we studied the involvement of MARCKS in the CCK-induced Amylase Release in rat pancreatic acini. Employing Western blotting, we detected MARCKS protein in the rat pancreatic acini. CCK induced MARCKS phosphorylation. A PKC-δ inhibitor, rottlerin, inhibited the CCK-induced MARCKS phosphorylation and Amylase Release. In the translocation assay, we also observed CCK-induced PKC-δ activation. An immunohistochemistry study showed that CCK induced MARCKS translocation from the membrane to the cytosol. When acini were lysed by a detergent, Triton X-100, CCK partially induced displacement of the MARCKS from the GM1a-rich detergent-resistant membrane fractions (DRMs) in which Syntaxin2 is distributed. A MARCKS-related peptide inhibited the CCK-induced Amylase Release. These findings suggest that MARCKS phosphorylation by PKC-δ and then MARCKS translocation from the GM1a-rich DRMs to the cytosol are involved in the CCK-induced Amylase Release in pancreatic acinar cells.
-
Involvement of phosphodiesterase 4 in β-adrenoceptor agonist-induced Amylase Release in parotid acinar cells
Journal of oral science, 2009Co-Authors: Keitaro Satoh, Ming-yu Guo, Nakayasu SairenjiAbstract:β-Adrenoceptor activation increases intracellular cAMP levels and consequently induces exocytotic Amylase Release in parotid acinar cells. Phosphodiesterase (PDE) catalyses the hydrolysis of cAMP, which terminates the downstream signaling of this second messenger. We investigated the involvement of PDE4, a cAMP-PDE, in β-adrenoceptor agonist-induced Amylase Release in mouse, rat and rabbit parotid acinar cells by using the specific PDE4 inhibitor rolipram. cAMP-PDE activity was detected in mouse, rat and rabbit parotid acinar cells. In the presence of rolipram, cAMP-PDE activity was reduced by about 31%, 38% and 33% in mouse, rat and rabbit parotid acinar cells, respectively. The increase in cAMP levels induced by the β-adrenoceptor agonist isoproterenol was enhanced in the presence of rolipram in mouse, rat and rabbit parotid acinar cells. Isoproterenol-induced Amylase Release, but not constitutive Amylase Release, was also enhanced in the presence of rolipram in mouse, rat and rabbit parotid acinar cells. These results suggest that the rolipram-sensitive cAMP-PDE, PDE4, is involved in β-adrenoceptor agonist-induced Amylase Release in parotid acinar cells. (J Oral Sci 51, 173-179, 2009)
-
Role of protein kinase C-delta in isoproterenol-induced Amylase Release in rat parotid acinar cells.
The journal of medical investigation : JMI, 2009Co-Authors: Hiroshi Sugiya, Keitaro Satoh, Ming-yu Guo, Miwako Matsuki-fukushima, Junko Fujita-yoshigakiAbstract:In parotid acinar cells, beta-adrenergic receptor activation results in accumulation of intracellular cAMP. Subsequently, cAMP-dependent protein kinase (PKA) is activated and consequently Amylase Release is provoked. In this paper, we investigated involvement of protein kinase C-delta (PKC delta), a novel isoform of PKC, in Amylase Release induced by beta-adrenergic receptor stimulation. Amylase Release stimulated with the beta-agonist isoproterenol (IPR) was inhibited by rottlerin, an inhibitor of PKC delta. IPR activated PKC delta and the effect of IPR were inhibited by a PKA inhibitor, H89. Myristoylated alanine-rich C kinase substrate (MARCKS), a major cellular substrate for PKC, was detected in rat parotid acinar cells, and a MARCKS inhibitor, MARCKS-related peptide, inhibited the IPR-induced Amylase Release. IPR stimulated MARCKS phosphorylation, which was found to be inhibited by H89 and rottlerin. These observations suggest that PKC delta activation is a downstream pathway of PKA activation and is involved in Amylase Release via MARCKS phosphorylation in rat parotid acinar cells stimulated with beta-adrenergic agonist.
-
Role of protein kinase C-δ in isoproterenol-induced Amylase Release in rat parotid acinar cells
The Journal of Medical Investigation, 2009Co-Authors: Hiroshi Sugiya, Keitaro Satoh, Ming-yu Guo, Miwako Matsuki-fukushima, Junko Fujita-yoshigakiAbstract:In parotid acinar cells, -adrenergic receptor activation results in accumula- tion of intracellular cAMP. Subsequently, cAMP-dependent protein kinase (PKA) is acti- vated and consequently Amylase Release is provoked. In this paper, we investigated in- volvement of protein kinase C-(PKC), a novel isoform of PKC, in Amylase Release in- duced by -adrenergic receptor stimulation. Amylase Release stimulated with the - agonsit isoproterenol (IPR) was inhibited by rottlerin, an inhibitor of PKC .I PR acti- vated PKCand the effect of IPR were inhibited by a PKA inhibitor, H89. Myristoylated alanine-rich C kinase substrate (MARCKS), a major cellular substrate for PKC, was de- tected in rat parotid acinar cells, and a MARCKS inhibitor, MARCKS-related peptide, inhibited the IPR-induced Amylase Release. IPR stimulated MARCKS phosphorylation, which was found to be inhibited by H89 and rottlerin. These observations suggest that PKCactivation is a downstream pathway of PKA activation and is involved in Amylase Release via MARCKS phosphorylation in rat parotid acinar cells stimulated with - adrenergic agonist. J. Med. Invest. 56 Suppl. : 368-370, December, 2009
Akane Imai - One of the best experts on this subject based on the ideXlab platform.
-
The small GTPase Rab33A participates in regulation of Amylase Release from parotid acinar cells.
Biochemical and biophysical research communications, 2015Co-Authors: Akane Imai, Maiko Tsujimura, Sumio Yoshie, Mitsunori FukudaAbstract:Amylase is Released from exocrine parotid acinar cells via typical exocytosis. Exocytosis of Amylase-containing granules occurs through several steps, including formation, maturation, and transport of granules. These steps are thought to be regulated by members of the small GTPase Rab family. We previously demonstrated that Rab27 and its effectors mediate Amylase Release from parotid acinar cells, but the functional involvement of other Rab proteins in exocrine granule exocytosis remains largely unknown. Here, we studied isoproterenol (IPR)-induced Amylase Release from parotid acinar cells to investigate the possible involvement of Rab33A, which was recently suggested to regulate exocytosis in hippocampal neurons and PC12 cells. Rab33A was endogenously expressed in parotid acinar cells and present in secretory granules and the Golgi body. Functional ablation of Rab33A with anti-Rab33A antibody or a dominant-negative Rab33A-T50N mutant significantly reduced IPR-induced Amylase Release. Our results indicated that Rab33A is a novel component of IPR-stimulated Amylase secretion from parotid acinar cells.
-
Evidence for Amylase Release by cyclin-dependent kinase 5 in the rat parotid
Archives of Biochemistry and Biophysics, 2010Co-Authors: Hiromi Shimomura, Akane Imai, Tomoko NashidaAbstract:Abstract Cyclin-dependent kinase 5 (Cdk5) plays no apparent role in cell cycle regulation, and Cdk5 is not activated by cyclins but only p35 or p39. Although the enzymatic activity of Cdk5 is highest in the central nervous system, recent reports indicate that it also has important functions in non-neuronal cells. In the present study, we investigated whether Cdk5 and its activators are expressed in rat parotid acinar cells, whether a β-adrenergic agonist enhances the expression of Cdk5, and whether Cdk5 mediates Amylase Release. We found that Cdk5 and its activator, cyclin I, were expressed in rat parotid acinar cells, and that the expression of Cdk5 was enhanced by treatment of the cells with isoproterenol. Amylase Release stimulated by isoproterenol was depressed by the addition of olomoucine, a Cdk5 inhibitor, or by the introduction of an anti-Cdk5 antibody. Cdk5 activity was enhanced by treatment with isoproterenol and this enhanced activity was attenuated by the addition of olomoucine. Olomoucine also attenuated both phosphorylation of Munc18c and translocation of Munc18c from the plasma membrane induced by isoproterenol. These results indicated that β-stimulation of rat parotid acinar cells enhanced the expression of Cdk5, and that this Cdk5 activation may mediate Amylase Release through phosphorylation of Munc18c.
-
Evidence for Amylase Release by cGMP via cAMP-dependent protein kinase in rat parotid acinar cells
Archives of oral biology, 2007Co-Authors: Hiroo Kuroki, Tomoko Nashida, Akane Imai, Hiromi ShimomuraAbstract:Abstract Amylase Release from the rat parotid gland is primarily mediated by a cAMP-dependent protein kinase (PKA). We previously reported that cGMP/cGMP-dependent protein kinase (PKG) signaling evokes Amylase Release. In the present study, we investigated whether cGMP-mediated Amylase Release might be due to cGMP/PKA signaling, as well as cGMP/PKG pathway. Activation of PKA by cGMP was required 100–1000-fold greater concentration than activation by cAMP in a parotid cytosol fraction. Synergistic activation of PKA by the combination of physiological cAMP and low concentration of cGMP was observed. Amylase Release from intact acinar cells was synergistically stimulated by the combination of diBu-cAMP and 8-pCPT-cGMP. cGMP dose-dependently stimulated Amylase Release from saponin-permeabilized parotid acinar cells. Phosphorylation by cGMP produced phosphorylated proteins of the same size as those produced by cAMP. Phosphorylation by cGMP was inhibited by the addition of PKA inhibitor, H-89. These results suggest that cGMP activates both PKG and PKA. Thus, it appears that both cGMP/PKG and cGMP/PKA pathways mediate Amylase Release from rat parotid acinar cells.
-
Evidence for the involvement of cAMP-GEF (Epac) pathway in Amylase Release from the rat parotid gland.
Archives of biochemistry and biophysics, 2004Co-Authors: Hiromi Shimomura, Akane Imai, Tomoko NashidaAbstract:Abstract Amylase Release from the rat parotid gland is mainly mediated in a cAMP-dependent protein kinase (PKA)-dependent manner. In the present study, Amylase Release mediated in cAMP-dependent and PKA-independent manners was investigated with a cAMP-regulated guanine nucleotide exchange factor (cAMP-GEF: Epac)-selective cAMP analogue, 8CPT-2Me-cAMP. The Epac was localized in the intracellular and the plasma membrane fractions. PKA activation by 8CPT-2Me-cAMP was 100-fold lower than that by cAMP. The Amylase Release (% of the total) from the intact parotid acinar cells was 16 and 3.6% by isoproterenol (1 μM) and 8CPT-2Me-cAMP (200 μM), respectively, and that from the saponin-permeabilized cells was 15 and 3% by cAMP (100 μM) and 8CTP-2Me-cAMP (10 μM), respectively. H-89 inhibited cAMP-induced Amylase Release, but did not inhibit 8CPT-2Me-cAMP-induced Amylase Release. These results indicated that Amylase Release by β-adrenergic stimulation is mediated through both the cAMP/PKA and cAMP/Epac signal pathways.
-
Influence of atrial natriuretic peptide on cyclic nucleotides and Amylase Release in rat parotid salivary gland in vitro.
Archives of oral biology, 1994Co-Authors: Tomoko Nashida, Akane Imai, Hiromi ShimomuraAbstract:Atrial natriuretic peptide (ANP), sodium nitroprusside and hydroxylamine increased cGMP accumulation in rat parotid acinar cells both in the presence and absence of forskolin but in a different manner. On the other hand, ANP decreased forskolin-stimulated cAMP accumulation, although sodium nitroprusside and hydroxylamine had no effect on cAMP accumulation. Amylase Release stimulated by forskolin, dibutyryl-cAMP or isoproterenol was depressed by ANP, whereas sodium nitroprusside and hydroxylamine did not evoke the inhibition of forskolin-stimulated Amylase Release. These results suggest that the inhibition of cAMP accumulation and of Amylase Release by ANP were not mediated via cGMP produced by guanylate cyclase-A.