Abstract
In line of development of inhibitory synapses, the transmission changes between the GABAergic and the glycinergic have been demonstrated in the brainstem and spinal cords. In this plasticity, it has been demonstrated that inhibitory transmitter released itself could developmentally change from GABA to glycine on the inhibitory afferent originated from the medial nucleus of the trapezoid body onto the lateral superior olivary nucleus (LSO). Because both GABA and glycine are carried into the synaptic vesicles by mean of inhibitory amino acid transporter, the transmitter released is supposed to be affected by the concentration of GABA and glycine in the terminals. Thus, we made whole-cell patch recordings in paired spinal cord culture neurons expressing both postsynaptic GABAA- and glycine-receptors. The inhibitory postsynaptic currents (IPSCs) evoked by electrical stimulation of the presynaptic neuron, evoked IPSCs were either GABAergic, glycinergic, or GABA and glycine co-release. Perfusion with a high concentration glycine in presynaptic neuron changed GABAergic or co-release neuron to co-release or glycinergic neuron, respectively. Furthermore, the application of GABA at a 100mM into the presynaptic neurons changed the transmission to the GABAergic dominant. These results suggest that transmitter switching in development could be contributed by the change of the transmitter content in the developing presynaptic terminal. [J Physiol Sci. 2008;58 Suppl:S133]
