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Biomedical subjects

R Yoshimura

Publications and source records attributed to R Yoshimura.

At least 127 records · Page 7Linked to original sources
PubMed1994

[Light therapy of patients with seasonal affective disorder].

Numerous investigators have shown a strong association between the seasons and the incidence of depression, mania and suicides. However, little has been known about patients who reveal affective episodes in association with the changing seasons year after year. Lewy and Rosenthal established the concept of Seasonal Affective Disorder (SAD). SAD is characterized by recurring cycles of fall-winter depression and spring-summer hypomania (or euthymia). Depressive symptoms often include hypersomnia, anergia, fatigue, carbohydrate craving and weight gain. The syndrome occurs predominantly in women and begins in late twenties. Lewy, Rosenthal and other investigators found that exposure of the SAD patients to bright artificial light improved depressive symptoms. Some hypotheses of light therapy are proposed, however, each of them has not well explained the mechanisms.

Cold Temperature↗
PubMed1993

Identification of the metabotropic glutamate receptor-1 protein in the rat trigeminal ganglion.

Anti-metabotropic glutamate receptor-1 monoclonal antibody was raised and applied for immunohistochemistry in the rat trigeminal ganglion. The antibody detected 145-kDa single band of protein in the immunoblot analysis. In immunohistochemistry, neurons in the trigeminal ganglion showed immunostaining with various intensity, almost irrespective of their cell size. The results indicate that metabotrophic glutamate receptors play an important role in somatic sensation together with ionotropic ones.

Amino Acid Sequence↗
PubMed1993

Localization of oxytocin receptor messenger ribonucleic acid in the rat brain.

The expression of oxytocin receptor (OT-R) mRNA in the rat central nervous system was examined by in situ hybridization histochemistry using cRNA probe. Wide distribution of cells expressing OT-R mRNA was observed not only in the hypothalamus, but also in other regions. There were high levels of OT-R mRNA in the anterior olfactory nuclei, tenia tecta, olfactory tubercle, rostral most region of the frontal cortex, piriform cortex, layers 2 and 3 of the neocortex, bed nucleus of the stria terminalis, anterior medial preoptic nucleus (AV3V region), magnocellular preoptic nucleus, supraoptic nucleus, paraventricular hypothalamic nucleus, retrochiasmatic nucleus, ventromedial hypothalamic nucleus, paraventricular thalamic nucleus, central amygdaloid nucleus, medial amygdaloid nucleus, posterior cortical amygdaloid nucleus, amygdalohippocampal area, subiculum, prepositus hypoglossal nucleus, and dorsal motor nucleus of vagus. In most regions of the brain, our findings concurred with those obtained by receptor binding autoradiography using a ligand specific to OT. However, in the inferior olive nucleus, OT-R mRNA was not detected despite an abundance of binding sites showed by receptor binding autography. Despite this discrepancy OT appears to have central nervous system functions in addition to its hormonal functions.

Animals↗
PubMed1993

The effects of cyclosporin on renal microsomal cytochrome P-450 systems.

The effect of CsA on the renal microsomal cytochrome P-450 system was examined by using two animal models. Male Lewis rats and male white rabbits were treated with olive oil alone (Group A) or with CsA (30 mg/kg/day, Group B) by oral gavage for 7 and 14 days. Blood urea nitrogen and serum creatinine levels were determined at serial intervals after administration of CsA. In rats, BUN and S-Cr were increased, indicating the development of nephrotoxicity in group B by the 14th day after administration; BUN 78.8 mg/dl, S-Cr 3.2 mg/dl, but not in group A (BUN 29.3 mg/dl, S-Cr 0.7 mg/dl). In the rabbit experiments, BUN and S-Cr significantly increased in group B after 7 days of treatment but not in group A. P-450 content of the kidney microsomes prepared from rat and rabbit was examined. The renal specific P-450 content in group A was 68.8 pmol/mg protein in rats and 52.1 pmol/mg protein in rabbits, whereas those in group B showed 135.6 and 221.0 pmol/mg protein at day 14, respectively. SDS-PAGE also showed a significant increase in the content of P-450 after the CsA administration. Kidney microsomal aminopyrine N-demethylase activities were increased about 2.5 and 1.7 fold in rats and in rabbits, respectively. Monooxygenase activities for laurate and prostaglandin A1 were not significantly changed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Postnatal development of mRNA specific for a metabotropic glutamate receptor in the rat brain.

We examined the ontogenesis of a subtype of metabotropic glutamate receptors, termed mGluR1, which is linked to phosphoinositide metabolism, in various regions of rat brain during neonatal development. Northern blot analyses of mGluR1 mRNA indicated that mRNA increased monotonously or remained at plateau levels during the first 5 weeks after birth. In situ hybridization analyses supported this conclusion. The result is in contrast with the reported development of the activity in excitatory amino acid-stimulated phosphoinositide turnover during the same period. The latter increases during the first few weeks and then decreases sharply.

Animals↗
PubMed1992

Effect of ciclosporin on cardiac output and regional blood flow in rats: ciclosporin-induced nephropathy and its prevention with calcium channel blocker.

The effect of ciclosporin (CS) on cardiac output (CO) and regional blood flow was studied using the microsphere method in heminephrectomized rats with and without renal arterial clamping prior to the administration of CS. The effect of a calcium (Ca) channel blocker, verapamil, was also examined on CS-induced nephropathy. CS at a dose of 40 mg/kg per day was given orally using a gastric tube for 7 days. Verapamil was given in the drinking water for 7 days. Significant increases in blood urea nitrogen (BUN) and serum creatinine (sCr) with a significant decrease in renal inulin clearance (CIn) were noted after 7 days of CS administration in both intact and ischemic-kidney groups, indicating the development of CS-induced nephropathy. The ischemic-kidney group showed a significantly severe nephropathy as compared with the intact-kidney group. As for change in CO and regional blood flow, CS caused a significant decrease in CO, renal blood flow (RBF) and brain blood flow, while hepatic arterial blood flow and muscular blood flow significantly increased. The renal outer cortical blood flow decreased markedly while the inner cortical blood flow remained unchanged. Although verapamil slightly but significantly decreased mean arterial blood pressure in CS-treated rats, CO and its distribution did not change. BUN and sCr were not significantly ameliorated in the intact-kidney group. However, in the ischemic-kidney group, verapamil caused a significant improvement in RBF, ameliorating CS-induced elevation of BUN and sCr, and a decrease in CIn.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Effects of verapamil on cyclosporine. A (CsA)-induced nephropathy in ischemic kidney model in rats: changes in systemic hemodynamics and hepatic and renal microsomal cytochrome P-450].

We have examined the effect of verapamil on CsA-induced nephropathy by measurement of systemic hemodynamics including each organ blood flow using the microsphere method in ischemic kidney model of hemi-nephrectomized Wistar rats. Hepatic and renal microsomal cytochrome P-450 contents and their enzyme activities were measured to study the correlation between CsA-induced nephropathy and induction of hepatic and renal microsomal cytochrome P-450. All rats were hemi-nephrectomized (l-nephrectomy) and were classified into the following 6 groups: 1) control groups, 2) CsA at a dose of 40 mg/kg per day orally for 7 days (CsA group), 3) Oral administration of verapamil for 7 days in the CsA group (CsA + V group), 4) 20 min clamping of the remaining right kidney pedicle (Ischemic, Is group), 5) CsA was administered in the Is group (Is + CsA group), 6) Addition of verapamil to CsA in the Is + CsA group (Is + CsA + V group). Verapamil was given in the drinking water and the average dose calculated from the amount of drinking was 4.7 +/- 1.0 mg/kg per day and 5.2 +/- 0.7 mg/kg per day for the CsA + V group and the Is + CsA + V group, respectively. CsA caused significant increases in BUN and serum creatinine (sCr) with a significant decreases in renal inulin clearance (CIn) in all groups. When compared with the Is group, CsA caused significant decreases in cardiac output and all organ blood flow especially in renal blood flow with significant increases in BUN and sCr in the Is + CsA group.2+ degree of nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗