Interaction between taurine and GABA(A)/glycine receptors in neurons of the rat anteroventral cochlear nucleus.

Taurine, one of the most abundant endogenous amino acids in the mammalian central nervous system (CNS), is involved in neural development and many physiological functions. In this study, the interaction between taurine and GABA(A)/glycine receptors was investigated in young rat (P13-P15) anteroventral cochlear nucleus (AVCN) neurons using the whole-cell patch-clamp method. We found that taurine at low (0.1mM) and high (1mM) concentrations activated both GABA(A) and glycine receptors, but not AMPA and NMDA receptors. The reversal potentials of taurine-, GABA- or glycine-evoked currents were close to the expected chloride equilibrium potential, indicating that receptors activated by these agonists were mediating chloride conductance. Moreover, our results showed that the currents activated by co-application of GABA and glycine were cross-inhibitive. Sequential application of GABA and glycine or vice versa also reduced the glycine or GABA evoked currents. There was no cross-inhibition when taurine and GABA or taurine and glycine were applied simultaneously, but the response was larger than that evoked by GABA or glycine alone. These results suggest that taurine can serve as a neuromodulator to strengthen GABAergic and glycinergic neurotransmission in the rat AVCN.