[K+ loss by the myocardial mitochondria in fibrillation due to enhanced intracellular intake of Ca2+].
Ventricular fibrillation developed in an isolated perfused rat heart one minute after Na+ concentration was reduced in the solution, with homogenate and mitochondrial amount of 45Ca increasing. Subsequent perfusion with a solution of normal composition rapidly resulted in spontaneous defibrillation of the heart and the recovery of baseline radioactivity in the homogenate and mitochondria. As mitochondrial Ca2+ increased, K+ decreased simultaneously. It is suggested that intensive myocardial K+ loss at ventricular fibrillation is due to K+ withdrawal from the mitochondria as they absorb Ca2+ coming in excess to myocardial cells.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D066298:In Vitro Techniques; D008929:Mitochondria, Heart / Q000378:metabolism*; D010477:Perfusion / Q000379:methods; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D014693:Ventricular Fibrillation / Q000209:etiology / Q000378:metabolism*
D002132:Calcium Radioisotopes; D011188:Potassium; D002118:Calcium
Poteria K+ mitokhondriiami miokarda pri fibrilliatsii, vyzyvaemoĭ usileniem vnutrikletochnogo vkhoda Ca2+.