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Reiji Yoshimura

Publications and source records attributed to Reiji Yoshimura.

9 recordsLinked to original sources
PubMed2003

Inhibition of the norepinephrine transporter function in cultured bovine adrenal medullary cells by bisphenol A.

We report here the effects of an environmental estrogen, bisphenol A, on norepinephrine (NE) transporter function in cultured bovine adrenal medullary cells. The effects of bisphenol A were compared to those of 17beta-estradiol. Bisphenol A significantly inhibited [3H]NE uptake by the cells in a concentration-dependent manner (1-100 microM). Kinetic analysis revealed that bisphenol A, as well as 17beta-estradiol, noncompetitively inhibited [3H]NE uptake. Bisphenol A and 17beta-estradiol inhibited the specific binding of [3H]desipramine to plasma membranes isolated from bovine adrenal medulla. As shown by Scatchard analysis of [3H]desipramine binding, bisphenol A increased the dissociation constant (K(d)) and decreased the maximal binding (B(max)), indicating a mixed type of inhibition. 17beta-Estradiol increased the K(d) without altering the B(max), thereby indicating competitive inhibition. The present findings suggest that bisphenol A inhibits the function of the NE transporter by acting on a site different from that of 17beta-estradiol in the adrenal medulla and probably in the brain noradrenergic neurons.

Adrenal Medulla↗
PubMed2003

Plasma levels of homovanillic acid and the response to risperidone in first episode untreated acute schizophrenia.

We have previously reported that risperidone might improve negative symptoms in schizophrenia by influencing noradrenergic neurons. In the present study, we focused on the clinical efficacy and mechanisms of risperidone towards positive symptoms in the acute phase of schizophrenia. Thirty-four patients meeting DSM-IV criteria for schizophrenia and treated with risperidone alone were evaluated regarding their clinical improvement using the Positive and Negative Syndrome Scale (PANSS) before and 2 weeks after risperidone administration, and blood samples were also drawn at the same times. Plasma concentrations of homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol were analysed by high-performance liquid chromatography with electrochemical detection. Plasma HVA levels in the responders to the risperidone treatment (more than 50% improvement in scores of positive symptoms in PANSS) were higher than those of non-responders before risperidone administration. Furthermore, there was a negative trend between changes in plasma HVA levels and improvement of total scores for positive symptoms in PANSS. These results suggest that higher levels of plasma HVA before risperidone administration might be a predictor of a good response to risperidone treatment, and the influence of risperidone on dopaminergic activity might be associated with its efficacy in treating symptoms of schizophrenia in the acute phase.

Acute Disease↗
PubMed2003

Higher plasma 5-hydroxyindoleacetic acid levels are associated with SSRI-induced nausea.

We investigated the association between selective serotonin reuptake inhibitors (SSRIs; paroxetine or fluvoxamine) and nausea with regard to plasma 5-hydroxyindoleacetic acid (p5-HIAA) levels. Forty-eight patients meeting the DSM-IV criteria for major depressive disorder and treated with paroxetine or fluvoxamine participated in this study. p5-HIAA levels after SSRI administration were significantly higher in the nausea group than those in the nonnausea group (nausea group: 8.0 +/- 4.6 ng/ml; nonnausea group: 3.6 +/- 2.2 ng/ml; p < 0.01). On the other hand, no significant difference was found between the nausea and nonnausea group in terms of p5-HIAA levels before each drug administration. These results suggest that SSRI-induced nausea is associated with serotonergic hyperactivity in the gastrointestinal tract.

Acetophenones↗
PubMed2003

[Double depression].

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Antidepressive Agents, Second-Generation↗
PubMed2002

Interaction between fluvoxamine and cotinine or caffeine.

We examined the relationships between plasma fluvoxamine concentrations and plasma levels of cotinine and caffeine, respectively, under steady-state conditions in 30 patients who met DSM-IV criteria for a major depressive disorder and who were being treated with fluvoxamine. The daily dosages of fluvoxamine ranged from 50 to 200 mg (mean +/- SD 108 +/- 42 mg). Eleven patients were smokers and the remaining 19 were nonsmokers. The plasma fluvoxamine concentrations were significantly higher in nonsmokers (0.92 +/- 0.40 ng/ml/mg) than in smokers (0.56 +/- 0.28 ng/ml/mg); in addition, a trend towards negative correlations was observed between the plasma fluvoxamine concentrations and the plasma cotinine levels, although it was not significant. Significant positive correlations were found between the plasma fluvoxamine concentrations and the plasma caffeine levels. These findings are compatible with those in earlier reports that cytochrome P450 1A2 plays a major role in fluvoxamine metabolism.

Adult↗
PubMed2000

Possible relationships between plasma carbamazepine-10,11-epoxide levels and antimanic efficacy and side effects in patients with schizoaffective disorde.

We examined the relationships of plasma levels of carbamazepine (CBZ) and its two major metabolites, carbamazepine-10,11-epoxide (CBZ-E) and carbamazepine-10,11-diol (CBZ-D), with antimanic efficacy and side effects in patients with schizoaffective disorder. Positive relationships were found among plasma concentrations of CBZ-E and the degree of clinical improvement and side effects, whereas neither plasma CBZ nor CBZ-D levels were correlated with the degree of clinical improvement or side effects. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2000

Changes in plasma monoamine metabolites during acute lithium intoxication.

A case of acute lithium intoxication is presented in which plasma levels of 3-methyoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) were longitudinally measured during the intoxication period. Plasma levels of MHPH and 5-HIAA, but not HVA were increased during the intoxication period. These results suggest that toxic levels of lithium concentration occurred due to transient enhancement of serotonin and noradrenaline function. Dopamine function was not affected. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗