Cyclic AMP facilitates slow-inactivating Ca2+ channel currents expressed by Xenopus oocyte after injection of rat brain mRNA.
Properties of voltage-sensitive Ca2+ channels expressed in the Xenopus oocyte after injection of rat brain mRNA were investigated using the whole-cell voltage-clamp method as depolarization-induced Ba2+ current, IBa. The apparent decay profile of IBa was considered to be the sum of a transient current (tau approximately 0.4 s) and a more sustained current (tau approximately 4 s). The sustained component was isolated by a weak depolarization from -20 to 0 mV, only detected in the mRNA-injected cells, and rather sensitive to omega-conotoxin GVIA. Moreover, increases in cytosolic cyclic AMP caused potentiation of the long-lasting current. These results suggest that slow-inactivating states of transplanted Ca2+ channels are preferentially modulated by cyclic AMP-dependent protein kinase.
D000818:Animals; D001464:Barium / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology*; D006168:Guinea Pigs; D007267:Injections; D007473:Ion Channels / Q000187:drug effects*; D008978:Mollusk Venoms / Q000494:pharmacology; D009865:Oocytes / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D014981:Xenopus; D020866:omega-Conotoxin GVIA
D007473:Ion Channels; D008978:Mollusk Venoms; D012333:RNA, Messenger; D001464:Barium; D020866:omega-Conotoxin GVIA; D000242:Cyclic AMP; D002118:Calcium