Alpha-chloralose opens the chloride channel of frog isolated sensory neurons

The effect of alpha-chloralose on the sensory neurons isolated enzymatically and mechanically from frog dorsal root ganglia was studied using a suction-pipette technique. The threshold concentration of alpha-chloralose was around 3 x 10(-5) M and the current produced by alpha-chloralose saturated at the concentration of 3 x 10(-3) M or more. The dose-response curve for alpha-chloralose provided a Ka value of 6 x 10(-4) M and a Hill coefficient of 1.8. The reversal potential of the response elicited by alpha-chloralose was close to the equilibrium potential for Cl- (ECl), indicating that the current was carried through Cl- channels. The current-voltage relationship indicated that there was little voltage dependence in the alpha-chloralose-induced response. The analysis of the variance of the alpha-chloralose-induced Cl- current fluctuations showed two types of the receptor-ionophore complexes with different channel conductances.