Different effects of capsaicin on I_A and I_K in pain-conduct neurons of rats

Abstract

The different effects of capsaicin on I_A and I_K currents in pain-conduct neurons of trigeminal ganglia (TG) were investigated. In cultured TG neurons of rats, whole-cell patch clamp techniques were used to record the I_A and I_K before and after capsaicin perfused. Results revealed that 1 μmol/L capsaicin could inhibit the amplitude of I_A by 48.2% (n=10,P<0.05), but had no inhibitory effect on I_K (n=7,P>0.05). Ten μmol/L capsaicin could significantly inhibit the amplitude of I_A by 93.2% (n=8,P<0.01), but only slightly inhibit the amplitude of I_K by 13.2% (n=7,P<0.05). Neither 1 μmol/L nor 10 μmol/L capsaicin had effects on the active curve of I_A and I_K. It was concluded that capsaicin could selectively inhibit the I_A current, and this effect might involve in the analgesic mechanisms of capsaicin.

Keywords

capsaicin / pain-conduct neurons / I_A current / I_A current / rat

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