title: High Ca content of pacemaker tissues in the frog heart.
abstract: 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.
mesh_terms: 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
chemical_list: D007444:Inulin; D012964:Sodium; D011188:Potassium; D002118:Calcium