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Biomedical subjects

M Otsuka

Publications and source records attributed to M Otsuka.

At least 505 records · Page 28Linked to original sources
PubMed1975

The synthesis and pharmacology of a novel benzodiazepine derivative, 1-(beta-methylsulfonylethyl)-5-(o-fluorophenyl)-7-chloro-1,3-dihydro-2H-1,4-benzodiazepin-2-one (ID-622).

The pharmacological profiles of a new benzodiazepine derivative, 1-(beta-methylsulfonylethyl)-5-(o-fluorophenyl)-7-chloro-1,3-dihydro-2H-1,4-benzodiazepin-2-one (ID-622), were shown. In anti-convulsant test, ID-622 was more potent than diazepam and medazepam when tested with pentylenetetrazol or bemegride, but was less potent than diazepam tested with strychnine or MES in mice. Taming effects of ID-622 were more potent than diazepam in both electroshock- and isolation-induced fighting mice tests, but were less potent in both septal rats and O.B. rats tests. ID-622 had only a weak influence on the spontaneous locomotor activity, and did not cause the righting reflex loss. In EEG, ID-622 increased fast activity and depressed hippocampal I-waves and amygdala after-discharge in cats. Acute toxicity of ID-622 was very low.

Animals↗
PubMed1975

Hypothalamic substance P as a candidate for transmitter of primary afferent neurons.

A peptide that exerts a depolarizing action on frog spinal motoneurons was found in the dorsal root of bovine spinal nerve. Pharmacological, chemical, and immunological properties of this motoneuron-depolarizing peptide were investigated and the results indicated that the peptide is identical with an undecapeptide, substance P, recently isolated from bovine hypothalamus by M.M. Chang and S.E.Leeman. The amount of hypothalamic substance P in bovine dorsal root determined by bioassay or radioimmunoassay was 24-130 pmole/g wet wt, whereas that in the ventral root was 9-27 times less. The effects of synthetic hypothalamic substance P on the isolated spinal cord of the frog and the newborn rat were studied. The peptide exerted a powerful depolarizing action on the motoneurons, its potency being about 200 times higher than that of L-glutamate. Distribution of substance P in the cat spinal cord was studied. The concentration of the peptide was highest in the dorsal part of dy lowered. When the dorsal root of the cat was ligated, substance P accumulated in a high concentration on the ganglion side of the ligature. These results, taken together, support the hypothesis that hypothalamic substance P is an excitatory transmitter of primary afferent neurons.

Animals↗
PubMed1975

Electrophysiological and behavioral effects of 1-methyl-5-(o-fluorophenyl)-7-chloro-1,3-dihydro-2H-1,4-benzodiazepin-2-one (ID-540) in cats and rabbits.

Effects of ID-540 (1-methyl-5-(o-fluorophenyl)-7-chloro-1,3-dihydro-2H-1,4-benzodiazepin-2-one) on the central nervous system were evaluated electrophysiologically and behaviorally in cats and rabbits. The reference compound used was diazepam. 1. ID-540 as well as diazepam produced muscle relaxation, grooming, facilitation of appetite and suppression of defensive behaviors. ID-540 made the animals lie on their side during sleep, but diazepam did not. 2. Though more effectively inducing an increase in fast activity and a decrease in frequency of hippocampal theta-waves than diazepam, ID-540 scarcely affected the amplitude of subcortical EEG (hippocampus, amygdala and hypothalamus), which diazepam decreased in cats. 3. ID-540 and diazepam increased the waking phase and decreased the paradoxical sleep phase. 4. ID-540 and diazepam at a dose of 1 mg/kg decreased the duration of amygdala after-discharge for 1 h in cats. Diazepam increased the duration of the after-discharge after it had been decreased, but ID-540 did not. ID-540 did not affect the duration of hippocampal after-discharge whereas diazepam prolonged it. 5. ID-540 depressed more effectively the hippocampal arousal response to stimulation of the ventro-medial hypothalamus than did diazepam in rabbits. 6. ID-540 depressed amygdalo-hippocampal evoked potential in cats. 7. ID-540 did not affect norepinephrine-induced pressor response but reduced hypothalamic pressor response in cats.

Animals↗