A model for cardiac ischemia. Cardiac cells transplanted into the renal capsular space of the rat and their electrophysiological properties.
We have developed a new model for electrophysiological studies on ischemic myocardium in situ. Pieces of ventricular tissue (1 X 1 mm) excised from the neonatal rat heart were transplanted into the renal capsular space of the adult rat of the pure strain F 344-NSlc. Electrophysiological properties of the transplanted cells during normal circulation and during ischemia induced by ligation of the renal artery were examined in situ 7-10 days later, when the tissues were fully vascularized, by means of conventional microelectrode techniques. Transmembrane potentials varied in individual cells, ranging from -60 to -90 mV. The amplitude, duration, and configuration of spontaneously occurring action potentials recorded from the transplanted cells were similar to those obtained in neonatal and adult rat myocardium. At 2-5 min after ligation of the renal artery, the frequency of the action potentials decreased markedly and their duration was transiently prolonged and then shortened. During the initial stage of ischemia (5-15 min), most of the cells were markedly depolarized and spontaneous activity ceased. Within 20-30 min, after the ligation, the cells did not respond to electrical stimulation. Reperfusion of the tissue by releasing the ligation restored the electrical activity of the cells within 15 min when a certain limited time of ischemia (30-40 min) was not exceeded.
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology; D008297:Male; D008955:Models, Cardiovascular; D009206:Myocardium / Q000166:cytology; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D013779:Tetrodotoxin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D013779:Tetrodotoxin; D014700:Verapamil