Tohoku university school of medicine

Synaptic transmission and its modulation in neurons of the central nervous system are studied using whole-cell patch-electrodes applied to brain slices from rats or mice. We apply transmitter substances including glycine, ACh or GABA to an identified single neuron using a "Y tube", and record the evoked currents. So far, our study has revealed that strychnine-sensitive glycine receptors are expressed in neurons of the deep cerebellar nuclei (DCN) of rats and that glycinergic transmission mediated by these receptors is functional in these neurons from stages immediately after birth. The glycinergic innervations are presumably supplied by small interneurons located in the DCN. We have also shown that in area postrema neurons of the rat nicotinic receptors are expressed at GABAergic presynaptic terminals and induce Ca2+ influx to trigger vesicular release. The major nicotinic receptors involved are thought to be heteromeric subtypes such as alpha3beta4 receptors, which may regulate inhibitory transmission potently responding to endogenous or exogenous nicotinic agents appeared in this area. Presently, we also study control mechanisms in rodent pinealocytes for their cellular activities including melatonin secretion with a combination of refined patch-electrode and “Y-tube” techniques.

1)Inhibitory synaptic transmission in area postrema neurons of the rat showing robust presynaptic facilitation mediated by nicotinic ACh receptors. Brain Research 1130: 83-94 (2007). This study indicates that nicotinic receptors are expressed at GABAergic presynaptic terminals in the area postrema and induce Ca2+ influx to trigger vesicular release. The major nicotinic receptors involved are thought to be heteromeric subtypes such as alpha3beta4 receptors, which may regulate inhibitory transmission potently responding to endogenous or exogenous nicotinic agents appeared in this area.
2)Discrete but simultaneous release of adenine nucleotides and serotonin from mouse megakaryocytes as detected with patch and carbon-fiber electrodes. American Journal of Physiology-Cell Physiol. 286: 119-128 (2004). This study shows that megakaryocytes store adenine nucleotides and serotonin in the same vesicle and release them simultaneously in a discrete manner.
3)Glycine receptors and glycinergic synaptic transmission in the deep cerebellar nuclei of the rat: a patch-clamp study. Journal of Neurophysiology 90: 3490-3500 (2003). This study suggests that the ionotropic glycinergic receptors are expressed transiently but profoundly in the developing cerebellum, and that the distributions of these receptors causing excitation are different at excitatory and inhibitory presynaptic neurons. The glycine receptors may play distinct roles in the maturation and organization of cerebellar neural circuits.
4)Glycine facilitates transmitter release at developing synapses: a patch clamp study from Purkinje neurons of the newborn rat. Developmental Brain Research 144: 57-71 (2003). This study suggests that the ionotropic glycinergic receptors are expressed transiently but profoundly in the developing cerebellum, and that the distributions of these receptors causing excitation are different at excitatory and inhibitory presynaptic neurons. The glycine receptors may play distinct roles in the maturation and organization of cerebellar neural circuits.
5)Acute synaptic modulation by nicotinic agonists in developing cerebellar Purkinje cells of the rat. Journal of Physiology 538: 87-102 (2002). This study indicates that the enhanced synaptic activities in Purkinje cells are induced via presynaptic nicotinic receptors on the excitatory and inhibitory interneurones, presumably on the proximal axons or somatodendritic domains of granule cells and basket cells in the cerebellar cortex. Interestingly, these nicotinic effects were remarkable in immature rats (P5-P10), but were barely detectable in older rats (more than 10 days of age), indicating that nicotinic ACh receptors are regulated developmentally and may play a novel role in the maturing cerebellum.

cerebellum, synapse, patch-electrode, brain slice, platelet, megakaryocyte, plasticity, receptor, bioinformatics, pinealocyte