Effect of coronary flow rate during calcium-free perfusion on the calcium paradox

52 Scanning electron microscopic studies of reaggregates of S.Yoneda,N.Ohte,T.Samoto heart muscle cells in culture. ,Srd.Internal Med,Nagoya City Univ. An atempt to clarify the characteristic difference of cultured heart cells between monolayer and reaggregate was made through scanning electron microscopy(SEM). On the 1 st day of rotation culture in a flask,the cells separated by trypsin solution from rat embryo heart contact loosely forming incomplate reaggregates of approximate 50~ diameter through S&M. The single cells revealed round and opale-like shape of approximate 5-7~ in diameter, On the 5th day, the cells gather and looked fused each other becoming reaggregates of approximately 500~ in diameter. However,the central part of the cells showed flat and numerous small microvilli and/or blebs. The pheriphery of the cells showed rufly. It will be concluded that the heart cells in reaggregates showed globular and opale-like fusing neighor cells,but the cells became flat in the central part and the periphery of the cells having rufly. These findings are quite different from the cells between the two types of the cultures.

EFFECT OF CORONARY FLOW RATE DURING CALCIUM-FREE PERFUSION ON THE CALCIUM PARADOX. H. Ohhara, H. Kanaide, M. Nakamura. Research Institute of Angiocardiology and Cardiovascular Clinic, Kyushu University Medical School, Fukuoka, Japan The effect of coronary flow rate during 5-minute of calcium-free perfusion on the calcium paradoxical injury upon reperfusion with 2.5mM calcium for 10 minutes was investigated in the isolated perfused rat heart. During the calcium-free perfusion, various coronary flow rates were obtained by perfusing hearts with various levels of perfusion pressure. The contractile tension development after reperfusion with calcium was found to be clearly dependent on the coronary flow rate during the calciumfree perfusion. The amounts of creatine kinase release, the extent of depletion in tissue high energy phosphates stores and the accumulation of tissue calcium increased with increasing the coronary flow rate during the calcium depletion period. These results suggested that the severity in myocardial injuries associated with the calcium paradox was directly influenced by the coronary flow rate during the calcium-free perfusion.