High Ca content of pacemaker tissues in the frog heart.
Cation contents of various cardiac regions were determined in the isolated perfused bullfrog heart. The Ca content was much higher in the pacemaker tissues (sinus venosus and atrio-ventricular ring muscle) than in the atrial or ventricular muscles even with extracellular Ca deficiency. A possible relationship between stored Ca and spontaneous pacemaker activity is discussed.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D006329:Heart Conduction System / Q000378:metabolism*; D007444:Inulin / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011898:Ranidae; D012964:Sodium / Q000378:metabolism; D014018:Tissue Distribution
D007444:Inulin; D012964:Sodium; D011188:Potassium; D002118:Calcium