calcimycin and tricaine

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.

Topics: 1-Methyl-3-isobutylxanthine; 4-Aminopyridine; 8-Bromo Cyclic Adenosine Monophosphate; Acetylcholine; Adenosine; Aminobenzoates; Aminopyridines; Animals; Atropine; Calcimycin; Colforsin; Cyclic AMP; Diterpenes; Female; Isoproterenol; Oocytes; Phosphodiesterase Inhibitors; Potassium; Receptors, Adrenergic, beta; Tetraethylammonium Compounds; Xenopus laevis