A small increment of external K concentration accelerates adrenomedullary catecholamine secretion induced by ouabain and metabolic inhibitors.
In the cat adrenal perfused with a medium containing ouabain, raising the external concentration of K to 10 mM abruptly increased the rate of catecholamine secretion. Increased response to 10 mM K were also observed in the adrenals treated with monoiodoacetate or cyanide, which was suggested to reduce the Na pumping activity indirectly. Since both the onset time and the magnitude of K-induced secretion are dependent on the concentration of external Na, it was suggested that a small increase of K concentration accelerates Ca influx in exchange for internal Na.
D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D002415:Cats; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007473:Ion Channels / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology*; D011190:Potassium Cyanide / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D013268:Stimulation, Chemical
D002395:Catecholamines; D007461:Iodoacetates; D007473:Ion Channels; D010042:Ouabain; D012964:Sodium; D011190:Potassium Cyanide; D011188:Potassium; D019807:Iodoacetic Acid