Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/100178
Type: Artigo de periódico
Title: Tetracaine Stimulated Extracellular Ca2+-independent Insulin Release
Author: Bordin S.
Carneiro E.M.
Bosqueiro J.R.
Boschero A.C.
Abstract: The effect of the local anesthetic, tetracaine, on 45Ca efflux, cytoplasmic Ca2+ concentration [Ca2+](i) and insulin secretion in pancreatic B-cells was studied. At a physiological level of [Ca2+](o), tetracaine (0.1-5 mM) dose-dependently inhibited insulin secretion induced by 22 mM glucose. Paradoxically, at the same glucose concentration but in the absence of external Ca2+, tetracaine dose-dependently increased insulin secretion. At a low glucose level (2.8 mM) tetracaine failed to affect secretion, either in the presence or absence of external Ca2+. At high (22 mM) or low (2.8 mM) glucose, [Ca2+], was increased by tetracaine in a dose-dependent manner. Tetracaine (2 mM) also increased the 45Ca efflux from isolated islets. This effect was of the same magnitude at both low and high glucose concentrations, and was independent of the presence of extracellular Ca2+. Finally, tetracaine increased 45Ca efflux from islets perifused in the presence of thapsigargin. In conclusion, our data indicate that tetracaine releases Ca2+ from a thapsigargin-insensitive store in pancreatic B-cells. Under suitable experimental conditions, insulin release can be elicited by a [Ca2+](o)-independent pathway. The existence of a ryanodine-like Ca2+ channel in pancreatic B-cells is proposed.
Editor: 
Rights: fechado
Identifier DOI: 10.1016/S0014-2999(97)89669-0
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0030611570&partnerID=40&md5=db9eb73b2736a1e0969deb22729d8942
Date Issue: 1997
Appears in Collections:Unicamp - Artigos e Outros Documentos

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