beta-Adrenergic induced K+ current in Xenopus oocytes: role of cAMP, inhibition by muscarinic agents.
The K+ current induced by isoprenaline acting on beta-adrenergic receptors in Xenopus laevis has been studied in oocytes still surrounded by their follicular cells and inner ovarian epithelium. Forskolin, an adenylate cyclase activator, induced a similar K+ current and when used at subliminal concentration it potentiated the current induced by isoprenaline. Inhibition of phosphodiesterase by methylisobutylxanthine also enhanced the response to isoprenaline. 8-Br-cAMP, a permeant analogue of cAMP also produced a K+ current. Acetylcholine produced a long lasting inhibition of the isoprenaline current. This inhibition was not seen in the presence of atropine. It is concluded that the K+ current induced by the activation of beta-adrenergic receptors in the oocyte is mediated by an intracellular rise of cAMP.
Van Renterghem
C
C
Renit-Soria
J
J
Stinnakre
J
J
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015761:4-Aminopyridine; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000109:Acetylcholine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D062365:Aminobenzoates / Q000494:pharmacology; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D005576:Colforsin; D000242:Cyclic AMP / Q000494:pharmacology / Q000502:physiology; D004224:Diterpenes / Q000494:pharmacology*; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011188:Potassium / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D014982:Xenopus laevis
D062365:Aminobenzoates; D000631:Aminopyridines; D004224:Diterpenes; D010726:Phosphodiesterase Inhibitors; D011943:Receptors, Adrenergic, beta; D013757:Tetraethylammonium Compounds; C003636:tricaine; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000001:Calcimycin; D001285:Atropine; D015761:4-Aminopyridine; D000242:Cyclic AMP; D000241:Adenosine; D007545:Isoproterenol; D000109:Acetylcholine; D011188:Potassium; D015056:1-Methyl-3-isobutylxanthine