Effects of apamin on alpha-adrenoceptor-mediated changes in plasma potassium in guinea-pigs.
An intravenous K+-sensitive electrode has been used to monitor plasma [K+] changes induced by adrenaline (1.4-6.8 micrograms kg-1) and amidephrine (14-340 micrograms kg-1) in anaesthetized guinea-pigs. A biphasic response consisting of an initial increase in [K+] followed, within 1 min, by a fall below baseline was observed with both agonists. Apamin (0.4-40 micrograms kg-1) reduced the hyperkalaemic phase of the response to amidephrine in a dose-related, non-competitive manner. The response to adrenaline was also reduced but to a lesser extent. Apamin caused little or no reduction of the hypokalaemic phase of the response to either agonist.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001030:Apamin / Q000494:pharmacology*; D001514:Bee Venoms / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology; D004983:Ethanolamines / Q000494:pharmacology; D006168:Guinea Pigs; D008297:Male; D011188:Potassium / Q000097:blood*
D000316:Adrenergic alpha-Agonists; D001514:Bee Venoms; D004983:Ethanolamines; D001030:Apamin; C016980:amidephrine; D011188:Potassium; D004837:Epinephrine