Biomedical subjects

K Hirate

Publications and source records attributed to K Hirate.

8 recordsLinked to original sources

PubMed1991

Characteristics of the ambulation-increasing effect of GBR-12909, a selective dopamine uptake inhibitor, in mice.

Behavioral effects of a dopamine uptake inhibitor, GBR-12909 (GBR), were evaluated by ambulatory activity in mice. The single administration of over 10 mg/kg of GBR, i.p. and p.o., significantly increased the ambulatory activity. The repeated administration of GBR, at only 10 mg/kg, produced a reverse tolerance to its ambulation-increasing effect. However, a cross-reverse tolerance was induced between GBR (10 and 20 mg/kg) and methamphetamine (2 mg/kg) in both directions. Furthermore, 5 mg/kg of GBR significantly enhanced the effects of methamphetamine, cocaine, imipramine, morphine, scopolamine and caffeine. R-THBP, a coenzyme of tyrosine hydroxylase, also enhanced the effect of GBR. In contrast, the ambulation-increasing effect of 10 mg/kg of GBR was markedly reduced by haloperidol, chlorpromazine, tetrabenazine, oxypertine, reserpine and alpha-methyl-p-tyrosine. On the other hand, the effect of GBR was only slightly and/or scarcely modified by apomorphine, caerulein, physostigmine, pilocarpine, N6-(L-2-phenylisopropyl)-adenosine and naloxone. The neurochemical experiment in rats, not in mice, revealed that GBR possessed more dominant action on dopaminergic systems than noradrenergic or serotonergic systems. However, the behavioral characteristics of GBR are similar to those of methamphetamine and cocaine, which possess less selective action than GBR on dopaminergic and noradrenergic systems.

Animals↗

PubMed1989

A brief brain ischemia produces morphological damage of hippocampal CA1 pyramidal cells without affecting the sensitivities of psychoactive drugs in two types of discrete avoidance tasks in Mongolian gerbils.

Effects of subcutaneous administration of psychoactive drugs: methamphetamine (0.13-1 mg/kg), chlorpromazine (0.5-2 mg/kg), physostigmine (0.05-0.2 mg/kg), scopolamine (0.031-0.5 mg/kg), pentobarbital (5-20 mg/kg), diazepam (0.5-2 mg/kg) and morphine (1.3-5 mg/kg) on discrete lever-press and shuttle avoidance responses were investigated in Mongolian gerbils that had received a brief (5 min) bilateral brain ischemic operation. Although some of the ischemic animals tended to show a retardation of acquisition of the avoidance responses, the established baselines were almost identical between the sham-operated and ischemic groups. In the lever-press task, morphine increased the response rate, whereas chlorpromazine, physostigmine, pentobarbital and diazepam decreased both the response and avoidance rates in a dose-dependent manner. In the shuttle avoidance task, both the response and avoidance rates were dose-dependently increased by methamphetamine, scopolamine and morphine, but chlorpromazine, physostigmine, pentobarbital and diazepam dose-dependently decreased them. These drug effects were almost the same between the sham-operated and ischemic groups. However, the ischemic-operation produced a significant loss of pyramidal cells in the CA1 sector of the hippocampus, the remaining level being less than 10% that of the sham-operated control animals.

Animals↗

PubMed1989

Breeder differences within Wistar strain rats in step-through type passive avoidance response.

Characteristics of acquisition and retention of the one-training and repeated-training passive avoidance responses of the step-through type were investigated in 3 lines of so-called Wistar strain rats: HLA:Wistar, JLA:Wistar and Std:Wistar and in F344/Du Crj rats. In the adaptation and the first acquisition trials in the repeated-training task, Std:Wistar rats took comparatively longer latency times to enter the dark chamber from an illuminated runway than the other lines and strain of rats. In contrast, JLA:Wistar rats took a number of trials to stay for 300 sec or longer in the runway. HLA:Wistar, Std:Wistar and F344/Du Crj rats showed similar response latencies in the first retention trial. JLA:Wistar rats showed the shortest latencies among 3 lines of Wistar and F334/Du Crj rats, exhibiting much poorer acquisition and retention abilities than the other rats. The response latencies in the retention trials were longer in the order of HLA:Wistar greater than or equal to F344/Du Crj greater than Std:Wistar greater than JAL:Wistat rats. These results suggest that there are marked breeder differences in their passive avoidance response even in the rats that have the same strain name.

Animals↗

PubMed1988

Breeder differences within Wistar strain rats in acquisition of discrete shuttle avoidance response and in sensitivity to chlorpromazine.

Characteristics of acquisition processes of discrete shuttle avoidance response were investigated in 3 lines of Wistar strain rats: HLA:Wistar, JLA:Wistar, Std:Wistar and in F344/Du Crj rats. Std:Wistar and F344/Du Crj rats rapidly acquired the avoidance response, showing an avoidance rate of higher than 90% until the middle stage of the 1st training session in which 120 trials were carried out, and they also maintained a high level of avoidance response in the latter sessions. HLA:Wistar and JLA:Wistar rats, however, exhibited a poorer acquisition of the avoidance response than Std:Wistar and F344/Du Crj rats. These two lines of Wistar rats finally achieved average avoidance rates of around 80% after 5 sessions of training and showed a long-lasting warm-up period in each session. Std:Wistar and F344/Du Crj rats had more resistance than the other two lines to extinction of the acquired avoidance response. Chlorpromazine (2-8 mg/kg, i.p.) suppressed the avoidance response in a dose-dependent manner. The sensitivities to chlorpromazine were higher in the order of JLA:Wistar greater than HLA:Wistar greater than Std:Wistar not equal to F344/Du Crj rats. These results suggest that there are major breeder differences even in the same strain of rats in their behavioral and physiological characteristics. The present results also suggest that Std:Wistar rats show extremely close characteristics with those of F344/Du Crj rats.

Animals↗

PubMed1987

Modification of drug-induced tremor by systemic administration of kainic acid and quisqualic acid in mice.

The effects of excitatory amino acids, kainic acid and quisqualic acid, on the tremorine- and harmaline-induced tremor were quantitatively examined in mice using the power spectral analyzing method. The severity of the tremor was determined quantitatively in terms of the cumulative sum of the mean square value of the data. Kainic acid enhanced the tremor induced by tremorine but depressed the tremor induced by harmaline. Quisqualic acid depressed the tremor induced by both tremorine and harmaline in a dose-dependent manner. Kainic acid shifted the frequency of each component of the tremor induced by tremorine to the high frequency side, but quisqualic acid did not affect the frequency of tremor of the tremor induced by tremorine. The frequency of tremor of the tremor induced by harmaline was shifted by both excitatory amino acids to the low frequency side, and another component of tremor in the power spectral densities developed, of which the mean square values were very small. The present results suggest that, at least in part, the glutamatergic system can take a role on the modification of drug-induced tremor.

Animals↗

PubMed1986

Depression of drug-induced tremor by a new isoxazol derivative in mice.

The effects of a newly synthesized compound, MLV-208, on drug-induced tremor were investigated in mice. The study involved a power spectral analysis of the random current induced by movement of a magnet attached to the mouse on a wire coil. To induce tremor, tremorine and harmaline were subcutaneously injected. The power spectral density function defined the frequency composition of the tremor, and its severity was determined quantitatively in terms of the mean square value of the data in any frequency range of concern. MLV-208 depressed the power spectral density of both the tremorine- and harmaline-induced tremors, but reduced more effectively the former than the latter. The peak frequency of the tremorine-induced tremor did not change in the presence of MLV-208, while MLV-208 sometimes developed a new peak of the power spectral densities of the harmaline-induced tremor in the low frequency side, in addition to the original tremor component.

Animals↗

PubMed1985

Further studies on quantification of drug-induced tremor in mice: effects of antitremorgenic agents on tremor frequency.

The effects of diazepam, dantrolene and atropine on drug-induced tremors were investigated in mice from the point of view of the tremor frequency. The study involved a power spectral analysis of the random current induced by movement of a magnet (attached to the mouse) on a wire coil. To induce tremor, tremorine and harmaline were subcutaneously injected. The power spectral density function defined the frequency composition of the tremor and its severity was determined quantitatively in terms of the mean square value of the data in any frequency range of concern. Diazepam markedly depressed the power spectral density of the tremorine- and harmaline-induced tremor and reduced the tremor frequency. With higher doses of diazepam, the peak frequency of the tremorine-induced tremor shifted to the lower frequency side as if the tremor components were taken into the component of the spontaneous motor activity. Dantrolene and atropine suppressed the power spectral density without affecting tremor frequency. The relationship between the change of tremor frequency and the site of action of antitremorgenic agents are discussed.

Animals↗

PubMed1984

[A quantitative analyzing method for drug-induced tremor].

A method for analyzing drug-induced tremor in mice was developed using a power spectral analysis of the random current induced by the movement of a magnet attached to a mouse on a wire coil. The power spectral density function defined the frequency composition of the drug-induced tremor, and the mean square value of the data in any frequency range of concern was determined.

Animals↗