Thermal Diversities of Two Na^+/H^+ Exchanges in Guinea Pig Red Cells  

作　　者：JI HONG-LONG 1Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, USA 

出　　处：《Biomedical and Environmental Sciences》2001年第3期171-179,共9页生物医学与环境科学（英文版）

摘　　要：Objective\ To test the effect of hypothermia on Na+/H+ exchange, activated by shrinkage and cytoplasmic acidosis. Method\ Amiloride-sensitive Na+ influx in guinea pig red cells was traced with isotope 22Na and intracellular Na+ concentration was measured by emission flame photometry. Result\ Amiloride-sensitive Na+ influx decreased linearly as a function of temperatures (about 37℃) in shrunken cells, but increased in acidified cells. The up-regulation of acid-induced Na+/H+ exchange by elevated temperature was enhanced by hypo-osmolarity. Less sensitivity of intracellular H+ site at 41℃ may be the mechanism for the inhibition of shrinkage-induced Na+/H+ exchange by elevated temperature. Heating-mediated explosive increase in the activity of acid-induced Na+/H+ exchange may be due to enhanced extracellular Na+ sensitivity and lower intracellular pH caused by acidic metabolites. Acid-induced Na+/H+ ewxchange contributes to cytoplasmic Na+ accumulation. Conclusion\ These two modes of Na+/H+ exchange with different response to elevated temperature may play different roles in the cellular pathogenesis of heatstroke.Objective\ To test the effect of hypothermia on Na+/H+ exchange, activated by shrinkage and cytoplasmic acidosis. Method\ Amiloride-sensitive Na+ influx in guinea pig red cells was traced with isotope 22Na and intracellular Na+ concentration was measured by emission flame photometry. Result\ Amiloride-sensitive Na+ influx decreased linearly as a function of temperatures (about 37℃) in shrunken cells, but increased in acidified cells. The up-regulation of acid-induced Na+/H+ exchange by elevated temperature was enhanced by hypo-osmolarity. Less sensitivity of intracellular H+ site at 41℃ may be the mechanism for the inhibition of shrinkage-induced Na+/H+ exchange by elevated temperature. Heating-mediated explosive increase in the activity of acid-induced Na+/H+ exchange may be due to enhanced extracellular Na+ sensitivity and lower intracellular pH caused by acidic metabolites. Acid-induced Na+/H+ ewxchange contributes to cytoplasmic Na+ accumulation. Conclusion\ These two modes of Na+/H+ exchange with different response to elevated temperature may play different roles in the cellular pathogenesis of heatstroke.

关 键 词：ANIMALS Cell Culture Techniques Erythrocytes Guinea Pigs Heat Stroke Hydrogen Ion Exchange Research Support  U.S. Gov't  Non-P.H.S. SODIUM Temperature 

分 类 号：R363[医药卫生—病理学]