Modulation of Cerebellar GABAergic Synaptic Transmission

Abstract

Synapses are the site of connections between various nerve cells to interact, where neural information is processed through the mechanisms of synaptic transmission mediated by chemical messengers, including excitatory and inhibitory neurotransmitters. Whereas signals at excitatory synapses are mediated by the amino acid glutamate, inhibitory signals are mainly mediated by γ-aminobutyric acid (GABA). Exploring the mechanisms underlying the synaptic transmission and changes in its strength is, therefore, essential for our understanding of brain functions. The inhibitory synapse plays a critical role in controlling various functions of the brain. However, the mechanisms that regulate the strength of transmission at inhibitory synapses are poorly understood than those that regulate excitatory synapses. Therefore, I have been interested in the roles of neuromodulators on inhibitory GABAergic synapses in the cerebellum, whose basic neural circuits and synaptic mechanisms have been more thoroughly investigated than have those of other regions of the mammalian central nervous system. This knowledge base would allow results of experiments on cerebellar synapses to be interpreted more easily. Consequently, our studies have revealed that GABAergic synapses in the cerebellum are well modulated by different neuromodulators (monoamines and purines) liberated by different synaptic inputs converging on the same inhibitory synapses.