TEMPERATURE-DEPENDENCE OF GAP JUNCTION PROPERTIES IN NEONATAL RAT-HEART CELLS

被引:47
作者
BUKAUSKAS, FF
WEINGART, R
机构
[1] DEPT PHYSIOL, BUHLPLATZ 5, CH-3012 BERN, SWITZERLAND
[2] KAUNAS MED ACAD, KAUNAS 2330001, LITHUANIA
来源
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY | 1993年 / 423卷 / 1-2期
关键词
NEONATAL RAT HEART; CARDIAC CELLS; GAP JUNCTIONS; ELECTRICAL COUPLING; TEMPERATURE;
D O I
10.1007/BF00374970
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
Cell pairs of neonatal rat hearts were used to study the influence of temperature on the electrical properties of gap junctions. A dual voltage-clamp method was adopted, which allowed the voltage gradient between the cells to be controlled and the intercellular current flow to be measured. Cell pairs with normal coupling revealed a positive correlation between the conductance of the junctional membranes, g(j), and temperature. Cooling from 37-degrees-C to 14-degrees-C led to a steeper decrease in g(j), cooling from 14-degrees-C to -2-degrees-C to a shallower decrease (37-degrees-C: g(j) = 48.3 nS; 14-degrees-C: g(j) = 21.4 nS; -2-degrees-C: g(j) = 17.5 nS), corresponding to a temperature coefficient, Q10, of 1.43 and 1.14 respectively. The existence of two Q10 values implies that g(j) may be controlled by enzymatic reactions. When g(j) was low, i. e. below 5 nS (conditions: low temperature; treatment with 3 mM heptanol), it showed voltage-dependent gating. This property was not visible when g(j) was large, i. e. 20-70 nS (conditions: high temperature; normal saline), presumably because of series resistances (pipette resistance). Cell pairs with weak intrinsic coupling and normally coupled cell pairs treated with 3 mM heptanol revealed a positive correlation between the conductance of single gap-junction channels, gamma(j), and temperature (37-degrees-C: 75.6 pS; -2-degrees-C: 19.6 pS), corresponding to a Q10 of 1.41.
引用
收藏
页码:133 / 139
页数:7
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