Tomonori Koizumi

Learn More
High doses of glycine have been reported to improve negative schizophrenic symptoms, suggesting that ingested glycine activates glutamatergic transmission via N-methyl-d-aspartate (NMDA) receptors. However, the pharmacokinetics of administered glycine in the brain has not been evaluated. In the present study, the time- and dose-dependent distributions of(More)
Electroencephalogram (EEG) alterations in rat after the i.v. administration of pentobarbital (PTB) and chlorpromazine (CPZ) were measured by power spectral analysis. The time courses of PTB concentrations in plasma, cerebrospinal fluid (CSF) and brain were determined after the i.v. administration of PTB (20, 40 mg/kg) by GC-MS. The PTB concentrations in(More)
Nateglinide is an antidiabetic agent metabolized by CYP2C9 and CYP3A4; hence inhibitors of these CYP isozymes may interact with nateglinide. There are, however, only limited in vitro data on how to predict drug-drug interactions in vivo. We examined the effects of 18 drugs that may be prescribed together with nateglinide (metformin, buformin, aspirin,(More)
We studied the effect of N(w)-nitro-L-arginine (NLA) on yak pulmonary vascular tone in a climatic (hypobaric/hyperbaric adjusted) chamber. Five young male yaks that had been born and reared at an altitude greater than 3800 m a.s.l. were used. After measuring control values, 20 mg/kg of NLA was administered via the jugular vein to each animal, and pulmonary(More)
  • T Koizumi
  • 2000
This review deals with pharmacokinetic/pharmacodynamic analysis of drugs. For the analysis of antipyretics, it was assumed that: (1) The rat body is divided into two compartments, core and skin. (2) Metabolic heat (M) is generated in the core compartment. (3) Heat loss by vaporization (V) is mainly originated from a respiratory effect and occurs in the core(More)
Nondepolarizing neuromuscular blocking drugs induce train-of-four (TOF) fade, i.e., the reduction of the fourth to the first twitch height in a train under TOF stimulation. It has been observed that the degree of TOF fade varies with the drug used and is inversely correlated with the potencies of the drug. In this study, the cause of difference of TOF fade(More)
The effects of low-dose x-rays (4 cGy) on mouse brain were examined. EEG recording were made on sleeping mice before, during and after exposure. Exposure to x-rays induced the immediate change in EEG pattern from a low-frequency and high-amplitude (sleep) to a high-frequency and low-amplitude (arousal). Repeated exposure caused a decrease in number of mice(More)
The degree of train-of-four (TOF) fade, i.e., the reduction of the fourth to the first twitch height in a train, induced by d-tubocurarine (d-TC) and alpha-bungarotoxin (alpha-BX) was investigated. The fade induced by d-TC was pronounced in comparison with that by alpha-BX, and the difference was analyzed using a kinetic model. Based on the assumptions: (1)(More)
The degree of twitch depression induced by nondepolarizing neuromuscular blocking drugs is known to be dependent on the stimulation frequency employed. Train-of-four (TOF) stimulations with different frequencies (0.67, 1.33 and 2.0 Hz) were delivered to a sciatic nerve of a rat and series of four twitch heights of a tibialis anterior muscle were measured(More)
Diuresis renography and water filling cystometry were simultaneously performed with the bladder full and with the bladder empty. The findings of diuresis renography with a full bladder were compared with those of diuresis renography with an empty bladder, in 9 patients (4 male and 5 female, mean 24.4 years old) with neurogenic bladder dysfunction. According(More)