par Van Eylen, Françoise;Antoine, Marie-Hélène 
;Lebrun, Philippe ;Herchuelz, André
Référence Fundamental & clinical pharmacology, 8, 5, page (425-429)
Publication Publié, 1994-10
;Lebrun, Philippe ;Herchuelz, André Référence Fundamental & clinical pharmacology, 8, 5, page (425-429)
Publication Publié, 1994-10
Article révisé par les pairs
| Résumé : | Na/Ca exchange was recently shown to regulate cytosolic free Ca2+ concentration ([Ca2+]i) in the pancreatic B-cell. The aim of the present study was to provide direct evidence that inhibition of the activity of the exchange may also increase insulin release. In the presence of extracellular Na+, caffeine stimulated 45Ca outflow but did not increase insulin release from islets perifused in the presence of 2.8 mM glucose. By contrast, in the absence of extracellular Na+, caffeine almost failed to increase 45Ca outflow and reversibly stimulated insulin release despite the fact that the absence of extracellular Na+ per se reduced basal insulin release. Similar findings were observed in islets perifused at a higher glucose concentration (8.3 mM) except that, in the presence of extracellular Na+, caffeine more markedly increased 45Ca outflow and stimulated insulin release. Our data provide direct evidence that inhibition of Na/Ca exchange with resulting blockade of Ca2+ outflow may increase insulin release from the pancreatic B-cell under suitable experimental conditions. |
