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Biomedical subjects

S Murai

Publications and source records attributed to S Murai.

At least 91 records · Page 5Linked to original sources
PubMed1992

Reversal by 3,3',5-triido-L-thyronine of the working memory deficit, and the decrease in acetylcholine, glutamate and gamma-aminobutyric acid induced by ethylcholine aziridinium ion in mice.

The effect of 3,3',5-triiodo-L-thyronine (T3) on working memory in ethylcholine aziridinium ion (AF64A)-treated mice was studied in a delayed non-matching to sample task using a T-maze. After behavioural testing was completed, mice were killed by microwave irradiation and regional brain levels of acetylcholine, aspartate, glutamate, glutamine, glycine, taurine, and gamma-aminobutyric acid (GABA) were measured by high-performance liquid chromatography with electrochemical detection. Treatment with AF64A (7 nmol, i.c.v.) produced a deficit in working memory performance in the non-matching to sample task at 30 s delay, and decreased acetylcholine, glutamate, and GABA levels in the hippocampus, but not in the septum and cerebral cortex. Administration of T3 (0.3 mg/kg, p.o., once daily for 6 days) to AF64A-treated animals improved the deficit in working memory performance and reversed the decrease in acetylcholine, glutamate, and GABA levels in the hippocampus. These results indicate that the deficit in performance induced by AF64A can be improved by T3 administration.

Acetylcholine↗
PubMed1992

A rapid assay for neurotransmitter amino acids, aspartate, glutamate, glycine, taurine and gamma-aminobutyric acid in the brain by high-performance liquid chromatography with electrochemical detection.

For simultaneous assay of the five neurotransmitter amino acids, Asp, Glu, Gly, Tau, and GABA in brain tissues, a very rapid and simple chromatographic method using high-performance liquid chromatography with electrochemical detection in combination with o-phthalaldehyde derivatization is described. Because the present method permits the determination of these five amino acids within less than five minutes in one chromatographic run, up to 100 samples a working day can be analyzed using an autosampler. Within-run coefficients of variation for these five amino acids were less than 2% (n = 20). The quantitative detection limit was 2.5 pmol for the 5 amino acids. The present method has been applied to the measurement of the five amino acid neurotransmitter levels in several discrete brain regions of mice treated with and without electroconvulsive shock.

Amino Acids↗
PubMed1992

Effects of nefiracetam, a novel pyrrolidone derivative, on brain monoamine metabolisms in mice.

The effects of acute and chronic administration of nefiracetam, a pyrrolidone derivative, on monoaminergic neurotransmitter systems in the mouse hippocampus, frontal cortex, hypothalamus, and striatum were studied. The levels of monoamines and of their metabolites were measured by high performance liquid chromatography with electrochemical detection on the first, 7th, and 14th days after nefiracetam was given. The neurochemical effects of nefiracetam were compared with those of oxiracetam and indeloxazine. Acute administration of nefiracetam (10 mg/kg, po) and oxiracetam (10 mg/kg, po) had no effect on the levels of noradrenaline (NA), dopamine (DA), or 5-hydroxytryptamine (5-HT), or on the levels of their metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA), in any of the regions examined. In contrast, a single dose of indeloxazine (10 mg/kg, po) decreased the levels of MHPG, DOPAC, and 5-HIAA in all regions examined. After chronic administration of nefiracetam (10 mg/kg, po, once daily), the levels of MHPG, DOPAC, and 5-HIAA were higher than control in all regions on the 14th day only. Oxiracetam (10 mg/kg, po, once daily) similarly increased the levels of MHPG, DOPAC, and 5-HIAA in the hippocampus, frontal cortex, and striatum, but not in the hypothalamus. Conversely, indeloxazine (10 mg/kg, po, once daily) decreased the levels of MHPG and 5-HIAA in all regions and the levels of DOPAC and HVA in the hippocampus and striatum as measured on the 7th and 14th days. These results show that nefiracetam has a delayed effect on brain monoaminergic metabolism, and that its effects are similar to those of oxiracetam, but clearly different from those of indeloxazine.

Animals↗
PubMed1992

Pharmacological properties of ceruletide in the vertical and horizontal locomotor activities of mice.

To clarify the pharmacological properties of ceruletide (CER) and cholecystokinin-octapeptide (CCK-8) with respect to vertical (VLA) and horizontal (HLA) locomotor activities of mice, effects of pretreatment with CER (0.5, 5, and 50 micrograms/kg, IP) and CCK-8 (5, 50, and 500 micrograms/kg, IP) on apomorphine (0.1 mg/kg, SC)- and clonidine (0.1 mg/kg, SC)-induced hypo-VLA and -HLA and on apomorphine (1 mg/kg, SC)-induced hyper-VLA and -HLA were examined. CER and CCK-8 had a dose-dependent inhibitory effect on VLA and HLA in intact mice. Pretreatment with CER had a biphasic effect (increase and decrease) on apomorphine- and clonidine-induced hypo-VLA, as well as an effect on apomorphine-induced hypo-HLA, a decreased effect on clonidine-induced hypo-HLA, and a decreased effect on apomorphine-induced hyper-VLA and -HLA. On the other hand, pretreatment with CCK-8 had no effect on apomorphine- and clonidine-induced hypo-VLA and -HLA and a decreased effect on apomorphine-induced hyper-HLA but not on hyper-VLA. These results suggest that for apomorphine- and clonidine-induced locomotion in mice CER has pharmacological properties different from those of CCK-8.

Animals↗
PubMed1992

Mice housed in a cage with a maze learn the maze without explicit training.

Mice were housed in a cage with a maze. A water tap was placed at the entrance of the maze. The exit of the maze connected with another cage (home cage). Food was placed in the home cage. Three different multiple mazes (types 1-3) were placed. 1) Mice were housed for 10 h a day in the apparatus and then removed to a normal cage for fasting. One trial per day was carried out after fasting for 13 h. In each trial, a mouse was put at the entrance of the maze and then the number of errors and the time till it reached the home cage was counted. Mice reached a learning criterion at Trial 2. 2) Administering scopolamine (0.125-0.5 mg/kg) 30 min before Trial four disturbed the maze work dose dependently in a type 3 maze, the most complex maze among the three, but did not in type 1 and 2 mazes. 3) Administering scopolamine (0.25-1.0 mg/kg) 30 min before Trial 11 to the mouse of the type 3 maze did not disturb the maze work. These results show that a mouse housed in a cage with a maze learns the maze without explicit training and scopolamine can differentially effect performance based upon the degree of training.

Animals↗
PubMed1992

Rapid and simultaneous assay of monoamine neurotransmitters and their metabolites in discrete brain areas of mice by HPLC with coulometric detection.

For simultaneous assay of the three monoamine neurotransmitters, norepinephrine, dopamine, and serotonin, and four respective metabolites in brain tissue, a rapid and simple method using high-performance liquid chromatography with coulometric detection is described. Because the present method permits the determination of these target substrates within 10 min or less in one chromatographic run, 150 samples can be analyzed using an autosampler and an integrator in a 24-h period. Within-run coefficients of variation for the target substrates in the standard solution and the whole brain sample were less than 3% and 2% (n = 40), respectively. The quantitative detection limits were 0.01-0.1 pmol. The present procedure was applied to measure the target substrates in several discrete brain areas in mice.

Animals↗
PubMed1992

A simple T-maze method for estimating working memory in mice. Effect of ethylcholine mustard aziridinium ion (AF64A).

Mice were housed in a cage containing a T maze. A watering place was located at the entrance of the maze. The right and left arms of the maze each had two exits, one of which led to the home cage where food was placed, while the other led to the watering place via a bypass. The exit leading to the home cage in either the right or left arm was alternately closed every 90 min. One-way swinging doors were inserted at the entrance to each arm and between each bypass and the watering place. The mice were given a cholinergic neurotoxin--ethylcholine mustard aziridinium ion (AF64A)--(8 nmol) or saline as a control into the left ventricle 2 weeks before they were housed in the apparatus. Those mice housed in this apparatus mastered the alternation task at a 5-sec delay on day 3 in the sham group and on day 4 in the AF64A group. When a longer delay (5-90 sec) was introduced for the mice that mastered the alternation task at 5-sec delay, the AF64A group made significantly more errors than did the sham group at 60- and 90-sec delays. These results show that the apparatus is useful in estimating working memory in mice with little effort.

Animals↗
PubMed1992

Delayed suppressive effect of a low dose of caerulein on the grooming behavior induced by the D1-receptor agonist SKF 38393.

Caerulein (CLN, 0.8-80 micrograms/kg, s.c.) was administered to male rats 10 min or 24 hr before the injection of SKF 38393 (3 mg/kg, i.p.). The increased mouth movement and grooming behavior by SKF 38393 were suppressed dose-dependently by CLN 10 min before the SKF 38393. CLN at the dose of 0.8 micrograms/kg, given 24 hr before the SKF 38393, suppressed the grooming behavior by SKF 38393. These findings suggest that a low dose of CLN, but not a high dose, had a delayed suppressive effect on the grooming behavior induced by an excess of D1-activity.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

[A simple method using a maze task for estimating working memory in mice].

Mice were housed in a cage with a T-maze for 7-9 h a day. A watering place was equipped at one end of the maze. At the other end of the maze, the right and left arms each have two exits, one of which leads to the home cage where food is placed, and the other of which leads to the watering place via a bypass. The exit leading to the home cage in either the right or left was alternately closed every two hours. One-way swinging doors were inserted at the entrance to each arm and between each bypass and the watering place. The mice housed in this apparatus acquired the alternation task at 5 s delay on the 6th day. As the delay became longer (5-150 s), correct response rate showed gradual decrease. Scopolamine (0.1-0.4 mg/kg) did not decrease correct response rate at 5 s delay, but did at longer delay (30 s and 60 s). These results suggest that this method is useful in estimating working memory of mice.

Animals↗
PubMed1991

The enhancement of the hypomotility induced by small doses of haloperidol in the phase of dopaminergic supersensitivity in mice.

Dopaminergic supersensitivity in mice was induced by pretreatment with a single injection of haloperidol (4.8 mg/kg). After the pretreatment, further treatment with haloperidol (0.6 or 0.01 mg/kg) was made at varying intervals, and catalepsy, locomotor activity and homovanillic acid (HVA) were measured. The intensity of the supersensitivity was evaluated by enhanced apomorphine (1 mg/kg)-induced climbing behavior. Supersensitivity was displayed on the 2nd and the 4th day. The cataleptogenic effect of haloperidol (0.6 mg/kg) was significantly weakened on the 1st, 2nd and 4th days. The motor inhibitory effect of haloperidol (0.01 mg/kg) increased on the 1st, 2nd and 4th days. Homovanillic acid was measured in the striatum and the prefrontal cortex on the 2nd day. Haloperidol (0.6 mg/kg) increased the concentrations of HVA in both regions of the brain. The increase in the concentrations of HVA in the striatum was blunted after the pretreatment, but such tolerance did not develop in the prefrontal cortex. Haloperidol (0.01 mg/kg) did not influence the concentration of HVA in both regions. These results suggest that the behavioral effect of a small dose of haloperidol may be enhanced, rather than reduced, in the phase of supersensitivity.

Animals↗
PubMed1991

[A simple multiple maze test to estimate learning and memory in mice: application to the effect of scopolamine on learning and memory].

The apparatus consists of a home cage, a maze cage and a starting box. A maze with four right-middle-left decisions was placed in the maze cage. The starting box was attached and a water tap was placed at an area corresponding to the entrance of the maze. The exit of the maze and the home cage are connected with a tunnel. Food was placed in the home cage. 1) Mice were housed for 10 hr a day in the apparatus and then removed to another cage for fasting. One trial a day was carried out after fasting for more than 12 hr. In each trial, a mouse was put at the starting box, and then the number of errors (entering a blind alley) and the time until the mouse reached the home cage were counted. The mouse passed through the maze with a small number of errors and time. 2) Administration of scopolamine (0.125-0.5 mg/kg, i.p.) to a mouse that had mastered the maze transiently disturbed the maze performance dose-dependently. 3) Mice were housed for 4 hr a day. Scopolamine (0.25 mg/kg, i.p.) was administered either before or after the housing. Scopolamine disturbed the maze performance in the case of both procedures. These results suggest that the method is useful for estimating the memory in mice.

Animals↗
PubMed1990

Effects of 24-hr fasting on methamphetamine- and apomorphine-induced locomotor activities, and on monoamine metabolism in mouse corpus striatum and nucleus accumbens.

The effects of 24-hr fasting on the vertical (VMA) and horizontal (HMA) locomotor activities, on cage climbing activity and on brain monoamine-related substances, were examined using male ddY mice. Both the VMA and HMA increased with fasting, but not the cage climbing activity. Methamphetamine (2 mg/kg, SC) increased the VMA and HMA in both the feeding and fasting mice, whereas with apomorphine (0.1 mg/kg, SC) both decreased. Furthermore, pretreatment with haloperidol (0.025 mg/kg, SC) showed no influence on the methamphetamine-induced VMA increase in both the feeding and fasting mice. However, pretreatment with haloperidol inhibited the methamphetamine-induced HMA increase in both the feeding and fasting mice and showed a higher level of HMA in fasting mice than in feeding mice. When measuring brain monoamine-related substances, the DA, NE, 5-HT, and 5-HIAA levels in the corpus striatum increased, whereas the 3-MT levels decreased. The monoamine levels in the nucleus accumbens of fasting mice were the same as those in feeding mice, except for a decrease of the 3-MT level. These results suggest that the locomotor activity in fasting mice may be increased by a change in the sensitivity of dopaminergic neurons in the corpus striatum.

Animals↗
PubMed1990

Very rapid and simple assay of taurine in the brain within two minutes by high-performance liquid chromatography with electrochemical detection.

We describe a very rapid and simple method for the assay of taurine (Tau) in the brain tissue, using high-performance liquid chromatography (HPLC) with electrochemical detection in combination with precolumn o-phthalaldehyde (OPA) derivatization. The present method permits Tau assay within 2 min in one chromatographic run. Recovery for Tau was 107.4 +/- 1.3% (SD, n = 10). Within-run coefficients of variation were +/- 1.6% (n = 15). The limit of quantitative detection of the method was 0.1 pmol for Tau. The present method has been applied to the measurement of Tau levels in several discrete brain areas of the mouse.

Animals↗
PubMed1990

The effect of arsenic trioxide on brain monoamine metabolism and locomotor activity of mice.

The arsenic trioxide (AsT) content, and monoamine levels in the cerebral cortex, hippocampus, hypothalamus and corpus striatum were determined in mice administered AsT (3 and 10 mg/kg) for 14 days. The vertical and horizontal motor activity was also examined. The AsT content in discrete brain areas differed but was clearly dose-dependent. Metabolites of norepinephrine and dopamine increased in the cerebral cortex, hippocampus and hypothalamus and decreased in the corpus striatum in AsT-treated mice. Metabolites of 5-hydroxytryptamine increased in all the discrete brain areas. The vertical and horizontal motor activity was increased by AsT at 3 mg/kg and decreased by AsT at 10 mg/kg. These results show that AsT modifies CNS metabolism and function at low doses. AsT penetrates the blood-brain barrier to cause these effects.

Administration, Oral↗
PubMed1990

[Measurement of the abrasion of radioactive teeth by dentifrices].

The purpose of this study is to assess the dentifrice abrasivity of both commercially available products and test products. The assessment of abrasivity was carried out by the measurement of 32P released from tooth by using radioactive dentifrice abrasion (RDA) method. In dentine, RDA values, which show the polishing ability for dentine, were 65-100 with dentifrices with normal cleaning power and 106-182 with those with high cleaning power, respectively. On the other hand, REA values which show the polishing ability for enamel were 12-405 with both market products and test products. The difference of the REA values according to the dentifrices appears to be largely influenced by the difference of polishing agents of each dentifrice. It is concluded that RDA method is usefull for assessing of dentifrice abrasivity. However, particular attention should be given to the abrasion of dentine.

Activation Analysis↗
PubMed1990

[A study of the relationship between hearing-aid usage and residual hearing].

Fifty-eight children (from 4 to 19 years of age) with bilateral, symmetrical, sensorineural hearing loss, who had used a hearing aid in only one ear for 1 to 19 years were investigated to study the influence of hearing-aid upon the residual hearing between the used and no used ears. The results were as follows, 1) The average hearing level for the used ear at seven frequencies was 49. 5 dB of pre-hearing-aid usage and was 53. 8 dB of post-hearing-aid usage. The discrepancy of audiograms between the aided and unaided ear was not remarkable. 2) The hearings for both the aided and the unaided ears in Audiograms was progressive for a long time. But no significance relation was observed between changes in used-ear hearing of the aided and unaided ears. 3) When the hearing levels of the children were scrutinised on an individual basis, it was found that 9 cases (15.5%) in both ears, 2 cases (3.4%) in only used ear and 1 case (1.7%) in only no used ear out of 58 cases showed deterioration of hearing. 4) These data did not lead us to the conclusion that hearing-aid usage was detrimental on the residual hearing of children with sensorineural hearing loss.

Adolescent↗
PubMed1990

[Some aspects of third molars with regard to the development of malocclusions].

Although the orthodontist is constantly aware of the developing third molar and its possible effects on the dentition during and after orthodontic treatment, the relationship between the third molar and the development of malocclusion had not been resolved. To attempt to clarify some of the problems associated with the third molar, an analysis of the factor in fluencing on the dentition and denture frame was performed. In this study, twenty-one adult cases which had no prothodontic correction of the tooth shape and orthodontic treatment with at least three wisdom teeth were used for evaluation of the denture frame structure and occlusion. The case which impacted third molar (M3 impacted group) showed less than 25 degree mandibular plane angle (FH-MP) without exception, while the case which the third molar erupted (M3 erupted group) were able to divide into high angle (more than 30 degree of FH-MP) and low angle (less than 29 degree of FH-MP) groups. The M3 impacted with low angle group and M3 erupted with low angle group showed relatively normal occlusion and favorable denture frame structure, but M3 erupted with high angle group indicated that the denture frame composition was affected by posterior discrepancy especially the steepness of occlusal plane which might be the over eruption of posterior teeth. The M3 erupted with high angle group also included two cases of severe anterior open-bite with skeletal deformity. These findings suggest that the posterior discrepancy due to existence of third molars influence on the dento-facial-skeletal structure and development of malocclusions.

Adult↗