Search PubMed⌕ Search

Biomedical subjects

Y Ida

Publications and source records attributed to Y Ida.

At least 55 records · Page 3Linked to original sources
PubMed1992

Vitamin B12 accelerates re-entrainment of activity rhythms in rats.

The effects of methyl vitamin B12 (5-6 mg/kg, p.o.) on the entrainment of circadian running wheel activity rhythm to a new lighting schedule were measured in rats. After the light-dark (LD) cycle was abruptly reversed, rats given vitamin B12 took less time to entrain their circadian locomotor activity rhythm to the new cycle than did controls. This result indicates that vitamin B12 accelerates the reentrainment of the mammalian circadian activity rhythm following an abrupt change in the environmental LD cycle.

Administration, Oral↗
PubMed1992

Effects of acute and repeated alcohol ingestion on hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal functioning in normal males.

We investigated the effects of acute and repeated alcohol ingestion on plasma levels of hormones associated with the functioning of the hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-adrenal (HPA) systems in normal males. In the first experiment, 7 normal male subjects were given ethanol (1.3 g/kg) in the form of a 43% alcohol solution of whiskey and water over a 30-min period (from 19:00 h to 19:30 h); blood samples were collected 30 min and immediately before the beginning of alcohol ingestion and then at intervals of 30 min for 180 min. Blood ethanol levels rose sharply and reached their maximum at 60 min, remaining above 1.0 mg/ml until 180 min. Prolactin levels increased, reaching a peak at 60 min, gradually returning to the initial value at 180 min. Decreased testosterone levels were observed only at 30 min. Luteinizing hormone (LH), adrenocorticotrophic hormone (ACTH) and cortisol levels did not show any increases. In the second experiment, 9 normal males were given the same dose of alcohol, but this was given on 7 consecutive evenings and the hormonal changes were examined on the 1st and 7th days, only at 30 and 60 min after alcohol ingestion began (during the period that blood ethanol levels were ascending to their peak). The results on the 1st day reconfirmed the findings in the first experiment and on the 7th day, the last alcohol ingestion produced increases in prolactin levels and decreases in testosterone levels at 30 and 60 min, but did not change other hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1992

Six new triterpenoidal glycosides including two new sapogenols from Albizziae Cortex. V.

Six new triterpenoid glycosides called julibrosides A1-A4, B1 and C1 were isolated from Albizziae Cortex, the dried stem bark of Albizzia julibrissin Durazz. Their structures were determined based on spectral and chemical evidence. Julibrosides B1 and C1 had new sapogenols, designated julibrogenin B and C, respectively, while julibrosides A3 included N-acetyl-D-glucosamine as a sugar component.

Carbohydrate Sequence↗
PubMed1991

Anxiogenic beta-carboline FG 7142 produces activation of noradrenergic neurons in specific brain regions of rats.

By measuring the levels of two major metabolites of rat brain noradrenaline (NA), 3-methoxy-4-hydroxyphenylglycol (MHPG) and 3,4-dihydroxyphenylglycol (DHPG), we investigated the effects of anxiogenic beta-carboline FG 7142, an inverse agonist of benzodiazepine (BZD) receptors, on brain noradrenergic activity of rats. Thirty min after treatment with FG 7142 (15 mg/kg IP), levels of both MHPG and DHPG in the hypothalamus, amygdala and thalamus, but not in the hippocampus and cerebral cortex, significantly increased. These increases were significantly antagonized by pretreatment with BZD receptor antagonist Ro 15-1788 (15 mg/kg, IP). Sixty min after treatment with FG 7142 at the same dose, significant increases in both metabolite levels occurred in the hypothalamus, amygdala, thalamus and cerebral cortex, and increases in MHPG levels only were observed in the hippocampus. These increases were significantly blocked by pretreatment with alpha 2-adrenoreceptor agonist clonidine (100 microgram/kg, IP). The present findings suggest that FG 7142 can produce increases in brain noradrenergic activity in specific brain regions by interacting with BZD receptors, and may support the hypothesis that hyperactivity of brain noradrenergic systems may be one neural mechanism in provocation of aversive emotional changes (anxiety, fear or panic).

Animals↗
PubMed1991

Different rates of acceptance of health examination among the people under 2 separate health insurance programs in Japan.

The entire population in Japan is covered by either workplace-based health insurance program or region-based health insurance program. While both programs were originally for curative medical care, only the former program has recently extended its financial support to preventive health examination. The attitude of the people toward health examination was studied in Miyagi prefecture in north-east Japan by questionnaires with more than 32,000 respondents to examine whether the difference in health insurance reflect on the rates of acceptance of 4 health examination items (i.e., blood pressure measurement, chest x-ray taking, and 2 screening tests for stomach and cervical cancer). Throughout the 4 items, the rate of acceptance was higher among those who were covered by workplace-based health insurance than among those covered by regional health insurance. The difference is large for the insured and less so for the family dependents of the insured. Further analysis for the preferred opportunities for health examination such as personal examination at clinics in contrast to region-based mass examination showed that the weight of clinics was quite large for the insured of national health insurance and their family dependents (i.e., 50% or even larger) but it was less so for the people covered by workplace-based insurance.

Blood Pressure Determination↗
PubMed1990

Pentobarbital attenuates stress-induced increases in noradrenaline release in specific brain regions of rats.

To examine whether anxiolytic action of drugs acting at the GABA/BZD-chloride channel complex may be related to the brain noradrenergic system, we investigated the effect of pentobarbital, a typical barbiturate which has potent GABA modulating properties, on increased NA release in nine brain regions of stressed rats. Pentobarbital (10 and 25 mg/kg) was injected IP 65 min before sacrifice (5 min before one-hour immobilization stress). Levels of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4), the major metabolite of brain noradrenaline (NA), and of plasma corticosterone, were fluorometrically determined. Pentobarbital treatment by itself increased MHPG-SO4 levels in the thalamus, locus coeruleus (LC) region, midbrain and basal ganglia of nonstressed rats. Stress produced increases in MHPG-SO4 levels in all brain regions examined and elevation of plasma corticosterone levels. Pentobarbital attenuated, in a dose-dependent manner, stress-induced increases in MHPG-SO4 levels in the hypothalamus, thalamus, anterior cerebral cortex, LC region and basal ganglia and also attenuated the stress-induced elevation of plasma corticosterone levels. These data suggest that pentobarbital can attenuate both stress-induced increases in NA release in specific brain regions as well as activation of the hypothalamo-pituitary-adrenocortical system. These attenuating effects may be related to the anxiolytic action of barbiturates.

Animals↗
PubMed1990

Enhancing effects of Ro 15-1788 on straw-climbing behavior as measured with the straw-suspension method: reversal by diazepam.

Ro 15-1788 (0.5, 1, 5, or 20 mg/kg), a pure benzodiazepine receptor antagonist, was studied for its effect on the duration of immobility and the number of straw-climbing attempts in a modified forced-swim test with straw-suspension of rats. A single dose of 20 mg/kg of Ro 15-1788 injected IP prolonged only the duration of immobility with no effect on straw-climbing behavior, whereas both doses of 1 and 5 mg/kg of this compound significantly enhanced the number of straw-climbing attempts in an inverted U-shaped manner. Ro 15-1788 at 1 mg/kg significantly reversed the inhibitory effect of 1 mg/kg of diazepam on the number of straw-climbing attempts. It is suggested that the enhancing effect of low doses of Ro 15-1788 on straw-climbing behavior can be regarded as an index of its anxiogenic effect, by acting via central benzodiazepine receptors.

Animals↗
PubMed1989

Met-enkephalin, injected during the early phase of stress, attenuates stress-induced increases in noradrenaline release in rat brain regions.

By measuring levels of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4), the major metabolite of noradrenaline (NA), we investigated the effects of Met-enkephalin (Met-ENK) ICV injected at three different stages of stress, i.e., 0 min, 5 min, or 10 min after exposure to immobilization stress. Immobilization stress caused significant increases in MHPG-SO4 levels in all brain regions examined, i.e., the hypothalamus, amygdala, thalamus, midbrain, hippocampus and locus coeruleus (LC), which suggests that stress increases NA release in these regions. Met-ENK at a dose of 50 micrograms, injected ICV immediately before stress exposure significantly attenuated stress-induced increases in MHPG-SO4 in the amygdala, thalamus and LC, but did not have such an effect when injected either 5 min or 10 min or 10 min after exposure to stress. Similarly, Met-ENK at 150 micrograms at 0 min significantly attenuated these increases in all brain regions examined, however, it did not do so when given at 5 min or 10 min after stress initiation. The amount of defecation and the weight loss caused by stress were also significantly attenuated by Met-ENK injected but only at 0 min. These results suggest that the attenuating effect of Met-ENK on stress-induced increases in NA release is greatly affected by the time of the peptide administration and that Met-ENK might inhibit stress-induced increases in NA release in these regions by affecting the initial changes induced by stress.

Animals↗
PubMed1989

Stressor predictability and rat brain noradrenaline metabolism.

This study examined the effects of stressor predictability on regional rat brain noradrenaline (NA) turnover, by measuring levels of a principal metabolite of NA (3-methoxy-4-hydroxyphenylethyleneglycol sulfate, MHPG-SO4). Male Wistar rats were exposed to one of three shock conditions for 19 hr: nonshock, signalled, and unsignalled shocks. Rats in the shock conditions received shock (1.2 mA intensity, 2 sec duration) on a 2.5 min variable time (VT) either preceded by a 12-sec, 10-W light signal (signal-shock interval of 10 sec) or not preceded by this signal. The tail electrodes for these rats were in series, so that the shock received by all rats was of exactly the same number and duration. After 19 hr in a VT-2.5 min shock session, the rats exposed to unsignalled shock (unpredictable group) showed significantly greater increases in MHPG-SO4 levels in the hypothalamus, amygdala, midbrain, cerebral cortex, thalamus and locus coeruleus, as well as in plasma corticosterone levels. Rats exposed to signalled shock (predictable group) showed significant increases in MHPG-SO4 levels in the first four of these regions, as compared to the nonshocked rats. Moreover, the unpredictably shocked rats exhibited greater elevations in MHPG-SO4 levels in the hypothalamus, amygdala, and thalamus, as well as in plasma corticosterone levels, when compared to the predictably shocked rats. These results are consistent with previous reports showing that unsignalled shock induced extensive somatic effects in comparison to signalled shock. The present study suggests that the presence of a signal attenuates the extent of NA release in some brain regions resulting from irregular inescapable shock stress.

Animals↗
PubMed1989

Opposite effects of diazepam and beta-CCE on immobility and straw-climbing behavior of rats in a modified forced-swim test.

The present study was undertaken to examine how two ligands of the benzodiazepine receptor, which possess anxiolytic or anxiogenic actions, affect both the duration of immobility and the incidence of straw-climbing behavior in rats in a modified forced-swim test. Rats were injected IP with either vehicle, diazepam (0.5, 1, 5 mg/kg), or beta-carboline-3-carboxylic acid ethyl ester (beta-CCE; 0.5, 1, 2, 5 mg/kg), or a combination of diazepam at 1 mg/kg and beta-CCE at 2 mg/kg. In addition, Ro 15-1788 (1 mg/kg), a specific benzodiazepine antagonist, was injected IP 20 min after diazepam injection and immediately after beta-CCE injection, respectively. In the first 5-min period of the forced-swim test, diazepam at 5 mg/kg prolonged the duration of immobility, whereas beta-CCE at 1, 2 and 5 mg/kg reduced its duration. Immediately after the first 5-min test period, 4 straws were suspended above the surface of the water, and the number of straw-climbing attempts and the duration of immobility were measured for a subsequent 5-min test period. Straw-suspension elicited straw-climbing behavior in forced swimming rats, resulting in a shortening of the duration of immobility in this period. All doses of diazepam inhibited straw-climbing attempts and prolonged the duration of immobility in a dose-dependent manner. beta-CCE at 1 or 2 mg/kg enhanced straw-climbing attempts, but did not significantly affect the duration of immobility. Furthermore, the combined administration of diazepam and beta-CCE antagonized the respective drug effects on the duration of immobility and the number of straw-climbing attempts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Blockade by diazepam of conditioned fear-induced activation of rat mesoprefrontal dopamine neurons.

The effect of diazepam on activation of the mesoprefrontal dopamine (DA) system by an emotional stress model without direct physical stimuli was examined. Environmental stimuli previously paired with inescapable footshock (conditioned fear) elicited increases in levels of the DA metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC), in the medial prefrontal cortex and of plasma corticosterone in rats. The increases in both levels were blocked by pretreatment with diazepam (5 mg/kg, IP); such blocking effects were reversed by Ro 15-1788 (15 mg/kg, IP), the benzodiazepine (BZD) receptor antagonist. These data suggest that diazepam can block activation of mesoprefrontal DA neurons as well as hypothalamo-pituitary-adrenocortical system elicited by the conditioned fear paradigm. This action appears to be a specific action of BZDs mediated through BZD receptors. We suggest that blocking effects of BZDs on the hyperactivity of the mesoprefrontal DA neurons may be one neural mechanism of their anxiolytic actions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Effects of neurotropin on regional brain noradrenaline metabolism in rats.

By measuring levels of noradrenaline (NA) and its major metabolite, 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4), in various rat brain regions, we investigated the effects of an extract isolated from vaccinia virus-inoculated and inflamed skin or tissue of rabbits (Neurotropin, NSP), administered acutely or chronically, on regional NA metabolism in stressed and nonstressed rats. An acute administration of NSP at 50 mg/kg significantly elevated MHPG-SO4 levels in the amygdala and cerebral cortex; and 100 mg/kg of the drug significantly increased the metabolite levels in the hypothalamus, amygdala, thalamus, midbrain, cerebral cortex and pons plus medulla oblongata without affecting NA levels. This suggests that acutely injected NSP slightly increases NA release in these brain regions. One hour immobilization stress caused significant increases in MHPG-SO4 levels, which were not affected by pretreatment with either 50 mg/kg or 100 mg/kg of NSP. Chronic injection with NSP daily at either 50 mg/kg or 100 mg/kg for 7 days was without effect on NA metabolism in all brain regions examined. However, increases in MHPG-SO4 levels caused by stress were significantly attenuated in some regions including the hypothalamus, amygdala and midbrain in chronic NSP-treated rats. This indicates that although an acute administration of NSP slightly increases brain NA release, a chronic treatment with NSP rather attenuates increases in NA release caused by immobilization stress in brain regions such as the hypothalamus, amygdala and midbrain. This suggests a possibility that these attenuating effects on stress-induced increases in brain NA release caused by chronic administration of NSP might be related to the stress-reducing or anti-stress properties of NSP.

Analgesics↗
PubMed1989

Possible contribution of green tea drinking habits to the prevention of stroke.

Among 5910 nondrinking and nonsmoking women (of greater than or equal to 40 years of age) in a prefectural city of Sendai, and two villages of Taijiri and Wakuya in Miyagi prefecture, Japan, medical history of stroke was less frequently observed among those who took more green tea in daily life. No relation with tea drinking was observed for hypertension history. The uneven distribution of stroke history was detectable even after the effects of age, location of residence, and high salt intake were ruled out. The incidence of stroke and cerebral hemorrhage during a 4-year follow-up of the study population was twice or more times higher in those who took less green tea (less than 5 cups a day) than in those who took more (greater than or equal to 5 cups daily).

Adult↗
PubMed1988

Expression of aggression attenuates stress-induced increases in rat brain noradrenaline turnover.

This experiment determined whether or not an aggressive biting response could attenuate stress-induced increases in brain noradrenaline (NA) turnover, by measuring contents of NA and its major metabolite, 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4), in discrete brain regions of male Wistar rats. Rats were exposed to a 10 min supine restraint stress with or without being allowed to bite a wooden stick. In each group, the animals were sacrificed by decapitation either 0 min or 50 min after release from stress. NA and MHPG-SO4 levels were unaffected in both biting and non-biting groups immediately after stress, as compared to controls. Fifty min after release from stress, increases in plasma corticosterone levels induced by stress recovered in the biting group but remained high in the non-biting group. MHPG-SO4 levels significantly increased in the hypothalamus, amygdala, thalamus, midbrain, basal ganglia, hippocampus and cerebral cortex in both stressed groups, however the increases in the non-biting group were significantly higher than those in the biting group in the first 5 of these regions. These findings clearly show that giving rats an opportunity to express aggression during stress exposure results in a significant attenuation of stress-induced increases in NA turnover in specific brain regions, such as the hypothalamus and limbic areas. The present experiment provides a possible neurochemical basis for clinical studies showing that suppression of anger in a stressful, frustrating situation leads to pathological consequences in humans.

Aggression↗
PubMed1988

Determination of reduced and total ubiquinones in biological materials by liquid chromatography with electrochemical detection.

A convenient and reliable liquid chromatographic (LC) method with electrochemical detection (ED) was developed for the determination of reduced (ubiquinol) and total ubiquinones in biological materials. After extraction of samples with n-hexane, ubiquinol was separated on a reversed-phase column and assayed directly by ED. In order to determine the total amount of a ubiquinone in biological samples, the unbiquinone was converted into the corresponding reduced form by treatment with sodium borohydride. No significant interfering peak (plastoquinol-9, ubichromenol-9, etc.) was observed in the elution areas of ubiquinol-7 to -11. This LC-ED method was about 70 times more sensitive than the previous LC-UV method and was able to detect 150 pg of ubiquinol-10. The method was applied satisfactorily to the determination of the contents of ubiquinol homologues in biological materials. The content of ubiquinols is a major component of the total ubiquinones in human plasma and urine and rat plasma and liver, but a minor component in rat heart and kidney.

Animals↗