Ryoji Miyoshi

Learn More
N-methyl-D-aspartate (NMDA) receptors are known to play an important role in learning and memory and to be involved in neuron cell death accompanying cerebral ischemia, seizures, and Alzheimer's disease. The NMDA receptor complex has been considered to consist of an L-glutamate recognition site, a strychnine-insensitive glycine modulatory site, and a(More)
The ontogeny of muscarinic acetylcholine receptors (mAChR) in the rat brain was studied with emphasis on the differentiation of M1- and M2-receptor subtypes through semi-quantitative in vitro autoradiography. [3H]Quinuclidinyl benzilate (QNB) and [3H]pirenzepine (PZ) were used for labeling total mAChR and M1-receptors, respectively. In the cerebral cortex(More)
The regional difference in the expression of c-fos mRNA induced by typical and atypical antipsychotics was determined in prefrontal cortex, striatum, N. accumbens and lateral septum in rats by in situ hybridization. Two typical antipsychotics, haloperidol (2 mg/kg) and fluphenazine (2 mg/kg), and three atypical antipsychotics, (-)sulpiride (100 mg/kg),(More)
Age-related changes of strychnine-insensitive glycine receptors in the rat brain were studied through quantitative in vitro autoradiography with 3H-glycine. 3H-glycine binding sites were most concentrated in the hippocampus, cerebral cortex, and olfactory tubercle, and moderate densities of binding sites were located in the striatum, nucleus accumbens,(More)
We investigated the effect of an NO synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA), on the levels of endogenous GABA in the rat striatum using in vivo microdialysis. Rats were perfused with the artificial CSF containing L-NMMA (0.1, 0.3 and 1.0 mM) or its inactive isomer D-NMMA (1.0 mM) for 1 h. Infusion of L-NMMA, but not its D-isomer,(More)
The effects of several calcium antagonists, including nicardipine, nifedipine, verapamil, and diltiazem, on muscarinic acetylcholine antagonist binding were studied in the P2 fraction of the rat cerebral cortex using either [3H]quinuclidinyl benzilate ([3H]QNB) or [3H]pirenzipine as the radioactive ligand. (1) The potency of [3H]QNB binding inhibition was(More)
The effect of somatostatin on muscarinic receptors (mAchR) was investigated through saturation experiments of [3H]oxotremorine-M-acetate and oxotremorine/[3H]N-methyl-scopolamine competition experiments. Somatostatin converted oxotremorine high affinity binding sites to low affinity sites in the hippocampus and cerebral cortex whose mAchR were dominantly of(More)
To elucidate the neuroprotective effect of nicotine, we investigated whether nicotine may attenuate dexamethasone potentiation of kainic acid-induced neurotoxicity. Primary hippocampal culture was pre-treated with nicotine for 24 h followed by dexamethasone (10(-4) M) for 24 h. Then, cultures were exposed with kainic acid (10(-4) M) and cellular viability(More)
The distribution of muscarinic acetylcholine receptors (mAChR) was investigated in the monkey brain by means of quantitative in vitro autoradiography. 3H-QNB, 3H-pirenzepine (PZ) and 3H-AF-DX 116 were used for labelling total mAChR, M1 and M2 receptors, respectively. 3H-PZ and 3H-AF-DX 116 showed specificity to each receptor subtype in the monkey brain. On(More)
The N-methyl-D-aspartate (NMDA) receptor complex has been considered to consist of an L-glutamate recognition site, a strychnine-insensitive glycine modulatory site, and a voltage-dependent cation channel. In this study, an effect of age on NMDA antagonist binding sites was investigated through quantitative in vitro autoradiography with(More)