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Hydrogen sulfide-induced inhibition of L-type Ca(2+) channels and insulin secretion in mouse pancreatic beta cells.
MedLine Citation:
PMID:  23275972     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
AIMS/HYPOTHESIS: L-type voltage-dependent Ca(2+) channels (VDCCs) in pancreatic beta cells play a critical role in regulating insulin secretion. The gasotransmitter H(2)S is mostly generated from L-cysteine in pancreatic beta cells by cystathionine γ-lyase (CSE) and has been reported to inhibit insulin release by opening ATP-sensitive K(+) channels. However, whether and how H(2)S affects VDCCs in beta cells is unknown. METHODS: The whole-cell patch-clamp technique was used to record VDCCs in beta cells from Cse (also known as Cth)-knockout (KO) and wild-type (WT) mice. Insulin secretion from pancreatic islets and endogenous H(2)S production in pancreas were measured. RESULTS: The H(2)S donor NaHS reversibly decreased L-type VDCC current density in a concentration-dependent fashion in WT pancreatic beta cells, and the current density was further inhibited by nifedipine. Furthermore, NaHS inhibited the channel recovery from depolarisation-induced inactivation, but did not shift the current-voltage (I-V) relationship. ACS67, another H(2)S donor, also inhibited L-type VDCCs in beta cells. Inhibiting CSE activity with DL-propargylglycine increased the basal L-channel activity of beta cells from WT mice, but not that of beta cells from Cse-KO mice. Beta cells from Cse-KO mice displayed higher L-type VDCC density than those from WT mice. Insulin secretion from pancreatic islets was elevated in Cse-KO mice compared with WT mice. NaHS dose-dependently inhibited glucose-stimulated insulin secretion, which was further inhibited by nifedipine. Bay K-8644 increased glucose-stimulated insulin secretion, but this was counteracted by NaHS and nifedipine. CONCLUSIONS/INTERPRETATION: Exogenous and endogenous H(2)S inhibit L-type VDCC activity and pancreatic insulin secretion, constituting a novel mechanism for the regulation of insulin secretion by the CSE/H(2)S system.
Authors:
G Tang; L Zhang; G Yang; L Wu; R Wang
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-30
Journal Detail:
Title:  Diabetologia     Volume:  -     ISSN:  1432-0428     ISO Abbreviation:  Diabetologia     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0006777     Medline TA:  Diabetologia     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
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