KINETICS OF THE CA2+-ACTIVATED K+ CHANNEL IN RAT HIPPOCAMPAL-NEURONS

被引:43
作者
YOSHIDA, A [1 ]
ODA, M [1 ]
IKEMOTO, Y [1 ]
机构
[1] KYUSHU UNIV,FAC MED,DEPT PHYSIOL,FUKUOKA 812,JAPAN
关键词
CA2+-ACTIVATED K+ CHANNEL; QUICK ACTIVATION; MINIMUM MODEL;
D O I
10.2170/jjphysiol.41.297
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The kinetics of the large-conductance Ca2+-activated K+ channel (235 pS in symmetrical 150 mM K+) were examined in the inside-out mode of the patch clamp technique. The open probability of the channel increased when [Ca2+]i, [Sr2+]i, or [Ba2+]i was increased. The [Ca2+]i-response relation was fitted with a Hill coefficient of 2 andhalf-maximum concentrations of 185, 80, 14.5, and 5.5-mu-M at -40, -20, +20, and +40mV, respectively. The channel was blocked by TEA or BA2+. The open-time histogram showed a single exponential component and the closed-time histogram showed at least two exponential components at various [Ca2+]i. Increasing [Ca2+]i decreased the time constant of the slow component of the closed-time histogram. Cell-attached patch recording revealed activation of the large-conductance Ca2+-activated K+ channel (BK channel) during the action potential. The deactivation time course was consistent with the fast after-hyperpolarization. A minimum model of the channel, close(2)-close(1)-open, where the transition from close(2) to close(1) requires the binding of 2 Ca2+, reconstructed quick activation of the channel if [Ca2+]i of 40-mu-M was assumed.
引用
收藏
页码:297 / 315
页数:19
相关论文
共 30 条
[1]   INTRACELLULAR CA2+ ACTIVATES A FAST VOLTAGE-SENSITIVE K+ CURRENT IN VERTEBRATE SYMPATHETIC NEURONS [J].
ADAMS, PR ;
CONSTANTI, A ;
BROWN, DA ;
CLARK, RB .
NATURE, 1982, 296 (5859) :746-749
[2]   DIHYDROPYRIDINE-SENSITIVE LOW-THRESHOLD CALCIUM CHANNELS IN ISOLATED RAT HYPOTHALAMIC NEURONS [J].
AKAIKE, N ;
KOSTYUK, PG ;
OSIPCHUK, YV .
JOURNAL OF PHYSIOLOGY-LONDON, 1989, 412 :181-195
[3]  
ALGER BE, 1988, J PHYSIOL-LONDON, V399, P191
[4]   VOLTAGE-SENSITIVE OUTWARD CURRENTS IN CAT MOTO-NEURONS [J].
BARRETT, EF ;
BARRETT, JN ;
CRILL, WE .
JOURNAL OF PHYSIOLOGY-LONDON, 1980, 304 (JUL) :251-276
[5]   PROPERTIES OF SINGLE CALCIUM-ACTIVATED POTASSIUM CHANNELS IN CULTURED RAT MUSCLE [J].
BARRETT, JN ;
MAGLEBY, KL ;
PALLOTTA, BS .
JOURNAL OF PHYSIOLOGY-LONDON, 1982, 331 (OCT) :211-230
[6]   THE MECHANISM OF ACTION OF BA-2+ AND TEA ON SINGLE CA-2+-ACTIVATED K+-CHANNELS IN ARTERIAL AND INTESTINAL SMOOTH-MUSCLE CELL-MEMBRANES [J].
BENHAM, CD ;
BOLTON, TB ;
LANG, RJ ;
TAKEWAKI, T .
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, 1985, 403 (02) :120-127
[7]   ON THE STOCHASTIC PROPERTIES OF SINGLE ION CHANNELS [J].
COLQUHOUN, D ;
HAWKES, AG .
PROCEEDINGS OF THE ROYAL SOCIETY SERIES B-BIOLOGICAL SCIENCES, 1981, 211 (1183) :205-235
[8]  
FABIATO A, 1979, J PHYSIOL-PARIS, V75, P463
[9]   CA-2+-ACTIVATED K+ CURRENT INVOLVEMENT IN NEURONAL FUNCTION REVEALED BY INSITU SINGLE-CHANNEL ANALYSIS IN HELIX NEURONS [J].
GOLA, M ;
DUCREUX, C ;
CHAGNEUX, H .
JOURNAL OF PHYSIOLOGY-LONDON, 1990, 420 :73-109
[10]   POTASSIUM CONDUCTANCE AND INTERNAL CALCIUM ACCUMULATION IN A MOLLUSCAN NEURON [J].
GORMAN, ALF ;
THOMAS, MV .
JOURNAL OF PHYSIOLOGY-LONDON, 1980, 308 (NOV) :287-313