在重新探討︰飯匙倩心臟毒所引發的紅血球能量耗解…問題之過程中的一些發現

Abstract

The action of Taiwan cobra cardiotoxin on intact human erythrocytes in plasma expander devoid of any inorganic salts had been investigated by Hsu & Lin in our laboratory. As indicated by them, a lag period existed between the time of addition of CTX and the time of onset of hemolysis and the hemolysis was preceded by the depletion of endogeneous ATP in erythrocytes. ( European J. Cell Biol.(1980) 22,222) In fact, because short of energy source material plasma expander can't afford a power to maintain the ATP levels of erythrocytes, the phenomenum of ATP depletion during the process of interaction of CTX with red cells that eventually results in hemolysis was worth reexamining. Using a buffer in which erythrocyte APP levels remain constant by at least 5 h to undertake the experiment, I found there is no signs for the depletion of intracellular ATP preceding the hemolysis induced by the cardiotoxin. A similar conclusion was achieved by performing the experiment in a buffer devoid of energy sources in a different way. An additional investigation into energy levels of the erythrocyte showed that the hemolysis induced by CTX occurred more rapidly under conditions where the intracellular ATP levels were higher. This specificity of CTX action on erythrocytes was manifested when compared with that of synthetic basic polypeptide, poly-L-lysine. It was found further that the depletion of endogenerous ATP accompanied the formation of aggregates containing spectrin. This implies that the hemolytical activity of CTX may have something to do with the status of some membrane proteins situated in cytoplasmic surface. To check whether membrane structure of erythrocytes incubated with CTX has been changed before hemolysis, the synergistic action of CTX with PLA was also studied. The result obtained shows that the rate of hemolysis was enhanced at its maximum when the molar ratio of CTX and PLA is 1:1. Based on above observations, together with the results of studying the interaction of CTX with liposomes by. others, I suggest that CTX can penetrate through cell membranes and target some proteins bound to the cytoplasmic surface of membranes. In addition, the effect regarding ionic composition of various buffer media on the extent of hemo- lysis was studied in this report.