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Biomedical subjects

M Hiramatsu

Publications and source records attributed to M Hiramatsu.

At least 19 recordsLinked to original sources
PubMed1992

Effect of naftidrofuryl oxalate on 5-HT2 receptors in mouse brain: evaluation based on quantitative autoradiography and head-twitch response.

The effects of naftidrofuryl oxalate (LS-121) on 5-HT2 receptors in the brain were assessed in mice on the basis of quantitative autoradiography and head-twitch responses. LS-121 inhibited [3H]ketanserin (2 nM) binding in all brain areas assayed in which there were 5-HT2 receptors, such as the frontal cortex, cingulate cortex, parietal cortex, occipital cortex, temporal cortex, nucleus accumbens, caudate-putamen, olfactory tubercle and hippocampus. In the frontal cortex, which has the highest density of 5-HT2 receptors, the Ki value of LS-121 was 6.08 x 10(-8) M. The inhibitory potencies of methysergide and ritanserin for 5-HT2 receptors were about 16- and 60-fold stronger, respectively, than that of LS-121. Moreover, in behavioral studies, LS-121 (12.5-50 mg/kg i.p.) produced dose-dependent and significant inhibitory effects on head twitches induced by 5-hydroxytryptophan (5-HTP) plus pargyline, which is a 5-HT2 receptor-dependent behavior in mice. These results suggest that LS-121 inhibits 5-HTP plus pargyline-induced head twitches by blocking 5-HT2 receptors.

5-Hydroxytryptophan↗
PubMed1992

Denervation of dopaminergic neurons with 6-hydroxydopamine increases nerve growth factor content in rat brain.

Denervation of dopaminergic neurons by intra nigral injection of 6-hydroxydopamine (6-OHDA) increased nerve growth factor (NGF) content in the cortex and hippocampus, both of which are innervated by cholinergic neurons. The increase continued during an observation period of 0.5-28 days after the lesion. The time course of changes in NGF content was quite different from that of cholinergic neuron denervation. The decreased dopamine content produced in the striatum by 6-OHDA injection was not recovered during the observation period. These results suggest that dopaminergic neuron damage may affect NGF synthesis.

Animals↗
PubMed1992

Involvement of the cholinergic system in the effects of nefiracetam (DM-9384) on carbon monoxide (CO)-induced acute and delayed amnesia.

The effects of N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl)-acetamide (DM-9384, nefiracetam), a cyclic derivative of GABA, were investigated in the carbon monoxide (CO)-induced amnesia model in mice using the passive avoidance task. Memory deficiency occurred when mice were exposed to CO before memory was completely consolidated after training (acute amnesia), at 7 days before training and 7 days after training (delayed amnesia). DM-9384 prolonged the step-down latency in mice with CO-induced amnesia. Scopolamine blocked the anti-amnesic effect of DM-9384 on delayed amnesia that had been induced by pre- or post-training exposure to CO. Bicuculline had a tendency to antagonize the anti-amnesic effect of DM-9384, but this tendency was not significant. Under these conditions, no significant change in the activity of choline acetyltransferase and glutamic acid decarboxylase was observed in the frontal cortex, striatum and hippocampus. These results suggest that DM-9384 potentiates cholinergic neuronal function and that it may modify acquisition and/or consolidation of memory.

Amnesia↗
PubMed1992

Free radicals, lipid peroxidation, SOD activity, neurotransmitters and choline acetyltransferase activity in the aged rat brain.

The mechanism of aging is suggested to be related to oxygen free radicals. Free radicals, lipid peroxidation and SOD activity have been reported to be increased in the aged brain. A Japanese herbal medicine, Sho-saiko-to-go-keishi-ka-shakuyaku-to (TJ-960), which has scavenging activities against hydroxyl radicals, superoxide, 1,1-diphenyl-2-picrylhydrazyl radicals, carbon-centered radicals and alpha-tocopheroxyl radicals, decreased carbon-centered radicals and thiobarbituric acid reactive substances (TBARS) levels in the aged rat brain after a 3-week oral administration of 5% TJ-960 solution. TJ-960 elevated superoxide dismutase (SOD) activity in the cytosol fraction of the hippocampus and hypothalamus of aged rats. It decreased norepinephrine and 5-hydroxytryptamine (5-HT) levels in the hypothalamus and increased the 5-HT level in the cerebellum. TJ-960 treatment increased choline acetyltransferase activity in aged rats. As herbal medicines do not generally have harmful side effects, antioxidant TJ-960 appears to be a suitable prophylactic agent against some neuronal symptoms of aging.

Aging↗
PubMed1992

Purification and characterization of formaldehyde dehydrogenase from rat liver cytosol.

Formaldehyde dehydrogenase was purified to electrophoretic and column chromatographic homogeneity from rat liver cytosolic fraction by a procedure which includes ammonium sulfate precipitation, DEAE-cellulose-, hydroxyapatite-, Mono Q-chromatography, and gel filtration. Its molecular mass was estimated to be 41 kDa by gel filtration and SDS-PAGE, suggesting that it is a monomer. It utilized neither methylglyoxal nor aldehydes except formaldehyde as a substrate. It has been reported that liver class III alcohol dehydrogenase and formaldehyde dehydrogenase are the same enzyme and oxidize formaldehyde and long chain primary alcohols. However, the enzyme examined here did not use n-octanoi as a substrate. The Km values for formaldehyde and NAD+ were 5.09 and 2.34 microM at 25 degrees C, respectively. The amino acid sequences of 10 peptides obtained from the purified enzyme after digestion with either V8 protease or lysyl endopeptidase were determined. From these results, the enzyme was proved to be different from the previously described mammalian formaldehyde dehydrogenase and is the first true formaldehyde dehydrogenase to be isolated from a mammalian source.

Aldehyde Oxidoreductases↗
PubMed1992

Synaptosomal membrane fluidity, lipid peroxidation and superoxide dismutase activity in the brain of amygdala-kindled rats.

Synaptosomal membrane fluidity, lipid peroxide (LPO) and cytosolic superoxide dismutase (SOD) activity were examined in various brain regions (amygdala, hippocampus, striatum and frontal cortex) of amygdala-kindled rats. At 24 h after the last seizure, a significant increase of membrane fluidity was observed in all the regions examined, whereas the LPO level was significantly decreased in the four regions with enhanced activity of cytosolic SOD. At 7 days after the last seizure, membrane fluidity was decreased only in the hippocampus. At 6 weeks after the last seizure, there were no changes in membrane fluidity between control and kindled rats. These results suggest that membrane fluidity and lipid peroxidation are modulated transiently by a kindled seizure, but not at a steady state of kindling with enduring seizure susceptibility.

Amygdala↗
PubMed1992

Increased superoxide dismutase activity in aged human cerebrospinal fluid and rat brain determined by electron spin resonance spectrometry using the spin trap method.

Superoxide dismutase (SOD) activity in CSF of patients was determined by electron spin resonance spectrometry using the spin trap method. Variation in SOD activity was found among patients. SOD activity in CSF of subjects increased with age and this was identified as Cu,Zn-SOD activity by electrophoresis. In addition, animal experiments showed that SOD activities were higher in mitochondrial and cytosol fractions of aged rats than in those of adult rats. This finding on aged rat brain validates the increase of SOD activity in aged human CSF.

Aging↗
PubMed1992

Japanese soybean paste miso scavenges free radicals and inhibits lipid peroxidation.

Japanese soybean paste miso, which has been reported to prevent gastric and mammary cancer and chronic nephritis, was demonstrated by electron spin resonance spectrometry using 5,5'-dimethyl-1-pyrroline-N-oxide as a scavenger of free radicals. Fifty mg/ml of miso scavenged 100% of 1,1-diphenyl-2-picrylhydrazyl radicals (3.9 x 10(15) spins/ml); 45 mg/ml quenched 92% of hydroxyl radicals (7.9 x 10(16) spins/ml); and 50 mg/ml quenched 50% of superoxide anion (6.7 x 10(16) spins/ml). In the system of rat cerebral cortex homogenate supplemented with 2 mM each of Fe2+ and ascorbic acid, 90% and 82% of the hydrogen and carbon-centered radicals having 1.7 x 10(13) spins/ml and 3.9 x 10(13) spins/ml, respectively, were quenched by 180 mg/ml of miso. The thiobarbituric acid-reactive substances, an index of lipid peroxidation in the brain, was inhibited by 10 mg/ml of miso. These results showed that miso acts as an antioxidant by scavenging free radicals.

Animals↗
PubMed1992

[Clinicopathological survey of persistent hypocomplementemic glomerulonephritis in children; correlation of DPGN and MPGN type I].

We studied clinicopathologically 19 patients with abnormal urinary findings accompanying with persistent hypocomplementemia under age 15. They consisted of 6 patients with membranoproliferative glomerulonephritis (MPGN) type I, 2 with MPGN type II, 2 with focal MPGN, 8 with diffuse proliferative glomerulonephritis (DPGN), 1 with focal glomerulonephritis (FGN). 17 cases were treated with steroid. In 2 patients with MPGN type I and 1 patient with DPGN, the treatment resulted in normalization of serum C3 level and urinary abnormalities and improvement of histological findings. In 3 patients with DPGN, urinary abnormalities and hypocomplementemia have been persisted and histological findings changed to those of MPGN type I. Thus, DPGN with hypocomplementemia seems to be an early stage of MPGN type I.

Adolescent↗
PubMed1991

A pharmacokinetic analysis of 3,4-methylenedioxymethamphetamine effects on monoamine concentrations in brain dialysates.

Interpretation of the in vivo actions of 3,4-methylenedioxymethamphetamine (MDMA) is complicated by the formation of the active metabolite, 3,4-methylenedioxyamphetamine (MDA). This study evaluates the role of MDA in the dopamine releasing actions of (+)-MDMA. In the study, rats were given subcutaneous doses of (+)-MDMA and concentrations of monoamines and their metabolites in striatal dialysate were measured at 15 min intervals. In parallel experiments, plasma concentrations of (+)- and (-)-MDMA and MDA were determined by GC/MS procedures. The time course of MDMA levels was comparable for the two isomers as were their bioavailabilities. In contrast, the plasma levels of MDA were about three times higher after (+)-MDMA. (+)-MDMA caused a rapid increase in striatal dialysate levels of dopamine and decreased extracellular levels of dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). There was a significant correlation between dopamine concentration in striatal dialysate and plasma MDMA concentration, but not with plasma MDA. These results indicate that MDMA itself has stereoselective actions on dopamine neurons. However, the higher plasma MDA levels after (+)-MDMA may account for part of the enantiomeric differences in the behavioral and neurotoxicological effects of MDMA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Decreased carbon centered and hydrogen radicals in skeletal muscle of vitamin E supplemented rats.

Carbon centered and hydrogen radicals were examined using electron spin resonance techniques with 5,5 dimethyl-2-pyrroline-1-oxide in the skeletal muscle of rats fed with a control diet and a vitamin E supplemented diet containing alpha tocopherol. Carbon centered and hydrogen radical levels in the white and red muscles and the soleus of these vitamin E treated muscle fibers were decreased. These results suggest that vitamin E directly quenches these free radicals.

Animals↗
PubMed1991

Pharmacokinetic and pharmacodynamic properties of some phencyclidine analogs in rats.

The pharmacodynamics and pharmacokinetics of three phencyclidine analogs, differing from phencyclidine (PCP) only in the nature of the amine structure, were determined after intravenous doses of equimolar amounts to rats. The purpose of the study was to assess the role of pharmacokinetics in the in vivo potency of the compounds. The compounds examined were phenylcyclohexyl-pyrrolidine (PCPY), diethylamine (PCDE), ethylamine (PCE), and phencyclohexylamine (PCA). The behavior responses monitored included ataxia and others previously shown to be characteristic of PCP. In contrast to their relative affinities for the MK 801 binding site, the behavioral potencies of PCE, PCDE and PCPY were comparable to PCP. The major discrepancy occurred with PCDE, whose affinity for the NMDA receptor was 1/20th of PCP. The pharmacokinetic studies showed that the discrepancy between in vivo and in vitro activity of PCDE could be partially accounted for by its conversion to PCE, a relatively potent PCP-like agent.

Animals↗
PubMed1991

Purification and tissue distribution of rat epidermal growth factor.

1. Two forms of rat epidermal growth factor, EGF-I and EGF-II, were purified to homogeneity from male rat submandibular glands. 2. The mol. wts of EGF-I and -II were estimated to be 5200 and 5400, respectively, both of them having an apparent biological activity. 3. The antiserum against EGF-II strongly cross-reacted with EGF-I; however, it did so only slightly with mouse or human EGF. 4. EGF was detected by radioimmunoassay in various tissues of male and female rats, and the concentrations of rat EGF in the submandibular gland, parotid gland, sublingual gland, and liver were significantly higher in the male than in the female.

Animals↗
PubMed1991

Free radical scavenging action of Bio-catalyzer alpha.rho No.11 (Bio-normalyzer) and its by-product.

Bio-catalyzer alpha.rho No.11 (Bio-normalyzer) and its by-product are natural health products made by yeast fermentation of glucose, Carica papaya Linn., Pennisetum pupureum Schum., and Sechium edule Swartz. Their effects on free radicals were examined by electron spin resonance spectrometry using spin trapping agent 5,5-dimethyl-1-pyrroline-1-oxide (DMPO). It was observed that both Bio-catalyzer and its by-product scavenged 95% of DMPO-OH spin adducts (89 x 10(15) spins/ml) generated by FeSO4-H2O2-diethylene triamine pentaacetic acid system at 45.45 mg/ml each. Five percent of DMPO-O2- spin adducts (27 x 10(15) spins/ml) generated by hypoxanthine-xanthine oxidase system and 11% of 1,1-diphenyl-2-picrylhydrazyl radicals (7 x 10(15) spins/ml) were quenched using 25 mg/ml of Bio-catalyzer while 5% of superoxide and nil DPPH radicals were scavenged by its by-product. Vivo tests showed that oral administration of 1-g/kg body weight of Bio-catalyzer significantly inhibited thiobarbituric acid reactive substances formation, which is an index of lipid peroxidation, in the FeCl3-induced epileptic focus of rats. These findings suggest that Bio-catalyzer or its by-product may be useful health foods against neural lipid peroxidation, traumatic epilepsy and aging.

Animals↗
PubMed1991

Effects of Guilingji on brain monoamines and their metabolites in mice.

Guillingji powder, a complex prescription of traditional Chinese medicines, has been pharmacologically shown to be a possible anti-aging agent, and also used for the treatment of male hypogonadism and female dysgenesis. Since the levels of numerous brain monoamines and their metabolites such as norepinephrine (NE), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), and 5-hydroxyindole acetic acid (5-HIAA) have been correlated with aging, we examined the effects of Guilingji powder and its extract on such monoamines and metabolites in the cerebrum and the cerebellum of mice using HPLC-ECD. The results showed that dietary intake of Guilingji powder had the effect of increasing the NE level and the DOPAC/DA ratio, and decreasing the 5-HT level and 5-HT/NE ratio in the cerebrum. In the cerebellum, the powder did not produce any changes in the levels of the compounds investigated. The extract of Guilingji, on the other hand, not only increased the NE level and the DOPAC/DA ratio but also the 5-HIAA/5-HT ratio in the cerebrum. However, the extract did not decrease the 5-HT in the cerebrum, although it decreased the 5-HT/NE. Unlike the powder, the extract had an effect in the cerebellum, which increased the DOPAC/DA ratio. These results suggest that Guilingji may have the action of modulating the levels and the metabolism of monoamines.

Animals↗