抄録
Activity of the deep cerebellar nuclei (DCN) takes an important role in outputting processed information from the cerebellum. In this study, we first investigated modulatory effects of serotonin (5-HT) receptor on GABAergic synapses in the rat DCN using whole-cell recordings in the cerebellar slices. Both of an endogenous agonist 5-HT and a 5-HT1 agonist 5-CT decreased the amplitude of stimulation-evoked IPSCs (eIPSC) in DCN neurons, and their effect was reversibly abolished by a 5-HT1A and 1B antagonist, cyanopindolol. Further, a selective 5-HT1A agonist 8-OH-DPAT had no effects of the amplitude of eIPSCs. Based on these results, the activation of 5-HT1B receptor is suggested to be responsible for decreasing the amplitude of eIPSCs. In the developing DCN neurons, we next examined developmental changes in both the kinetics of GABAergic postsynaptic currents and the modulatory effects of 5-HT on GABAergic synapses in the rat DCN neurons. At younger stage (around P14), eIPSCs showed slower kinetics and were more susceptible to the 5-HT-induced modulation than those at older stage (around P21). These pre- and postsynaptic parameters showed time-matched changing during development. These results suggest that the information flow from the cerebellar cortex is finely controlled at younger developmental stages, which is important to form the normal cerebellar function in the adult. [J Physiol Sci. 2006;56 Suppl:S170]
