Taurine-activated chloride currents in the rat sacral dorsal commissural neurons

The electrophysiological and pharmacological properties of taurine (Tau)-activated Cl- currents (ITau) were investigated in the dissociated rat sacral dorsal commissural nucleus (SDCN) neurons using the nystatin perforated patch recording configuration under voltage-clamp conditions. The reversal potential of ITau was close to the Cl- equilibrium potential. The ITau was not affected by a preceding GABA response but cross-desensitized by a preceding glycine (Gly) response. Strychnine (STR), picrotoxin (PIC), bicuculline (BIC) and Zn2+ suppressed the ITau in a concentration-dependent manner. The pharmacology of the ITau and Gly-induced response (IGly) was similar, though Zn2+ inhibition on ITau differed from that on IGly in being much slower in recovery. Serotonin potentiated the ITau via protein kinase C. The results indicate that both Tau and Gly act on a strychnine-sensitive site to open the same Cl- channels in the SDCN neurons, and suggest that Tau may act as a functional neurotransmitter in the mammalian SDCN.