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Apamin sensitive component of Ca~(2+)-activated K~(+)+current of afterhyperpolarization，I_(AHP)，in dorsal root ganglion neurons in rat

Chen Limin, Hu Sanjue, Wei Gengze

Departmernt of Physiology，The Fourth Military Medical University. Xi'an 710032,China

Abstract

Whole-cell voltage clamp technique was used to record the tail current in freshly isolated dorsal root ganglion (DRG) neurons of rat with an aim to investigate whether these neurons possess an apamin sensitive component of Ca~(2+)-activated K~(+) current,I_(AHP).The results are as follows: (1) the amplituds of the tail currents increased from 9.3 ±2.8 pA to 64.1 ± 3.4 pA (P<0.001) when the depolarizing duration was increased from 1 ms to 180 ms; (2) the amplitudes 0f the tail current were reduced when repolarizing pulses were applied, with a reversal potential of about-63 mV; (3) the amplitude of the tail current was significantly depressed or even almost completely blocked by extracellularly applied 500 #mu#mol/L Cd~(2+) or intracellularly applied 11 mmol/L EGTA;(4) the amplitudes of the tail currents were decreased by about (26.32±3.9)% (P<0.01 ) after 200 nmmol/L apamin was extracellularly applied; and (5) the fast component of the tail current was sensitive to 10 mmol/L TEA while the slow component was insensitive.

Key words: Ca~(2+)-activated K~(+) current;Dorsal root ganglion;Afterhyperpolarization

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Citing This Article：

Chen Limin, Hu Sanjue, Wei Gengze. Apamin sensitive component of Ca~(2+)-activated K~(+)+current of afterhyperpolarization，I_(AHP)，in dorsal root ganglion neurons in rat. Acta Physiol Sin 1998; 50 (2): (in Chinese with English abstract).