Search PubMed⌕ Search

Biomedical subjects

S Ueki

Publications and source records attributed to S Ueki.

At least 145 records · Page 8Linked to original sources
PubMed1985

[Behavioral pharmacology of amantadine with special references to the effect on abnormal behavior in mice and rats].

Behavioral effects of amantadine, especially on abnormal behavior in mice and rats, were reevaluated, in comparison with those of tricyclic antidepressants, methamphetamine and L-DOPA. 1) Amantadine at 10 approximately 50 mg/kg, i.p., tended to decrease ambulation and rearing in rats and mice. The drug at 50 mg/kg, i.p., caused piloerection and hyperirritability and at doses over 80 mg/kg, i.p., it impaired coordinated motor activity in rats. 2) Amantadine inhibited methamphetamine-induced hyperactivity, but apomorphine-induced stereotyped behavior was unaffected in rats. 3) Amantadine was equipotent to imipramine in suppressing haloperidol-induced catalepsy in rats, but L-DOPA was without effect. On the other hand, amantadine was 40 and 400 times as potent as imipramine and L-DOPA, respectively, in suppressing delta 9-tetrahydrocannabinol (THC)-induced catalepsy in rats. 4) Amantadine was as potent as imipramine in suppressing the muricide of olfactory bulbectomized rats, but was 3.5, 8.8 and 225.5 times as potent as methamphetamine, imipramine and L-DOPA, respectively, in inhibiting THC-induced reversible muricide in rats. 5) Amantadine at 50 mg/kg did not elicit circling behavior in the rat with unilateral nigral lesion induced by 6-hydroxydopamine. 6) Amantadine at high doses caused irritable aggression characterized by squealing in rats pretreated with intraventricular 6-hydroxydopamine. The most important characteristic of amantadine is its prominent effect suppressing the THC-induced catalepsy and muricide. This may be a reflection of the feature of amantadine activating the dopaminergic as well as the serotonergic systems.

Aggression↗
PubMed1985

[Behavioral and electroencephalographic effects of lormetazepam].

Behavioral and electroencephalographic effects of lormetazepam were investigated in rats, mice and rabbits, in comparison with those of diazepam, nitrazepam and flurazepam. Locomotor activity of mice in an open-field situation was decreased with large doses of lormetazepam and diazepam, while it was increased with nitrazepam and flurazepam. The anticonflict effect of lormetazepam in rats was much more potent than those of diazepam, nitrazepam and flurazepam. In suppressing the muricide of olfactory bulbectomized and raphe lesioned rats, lormetazepam was more potent than diazepam, nitrazepam and flurazepam. Lormetazepam, diazepam and flurazepam prevented both maximal electroshock and pentetrazol convulsions in mice, the effects on the latter being much more potent than those on the former. Lormetazepam was more potent than diazepam and flurazepam in potentiating thiopental-, ether- and ethanol anesthesia, impairing rotarod performance and in muscle relaxant activity. In conscious rabbits with chronically implanted electrodes, lormetazepam induced a drowsy EEG pattern and suppressed the EEG arousal responses not only to auditory stimulation but also to electrical stimulation of the midbrain reticular formation or hypothalamus. Lormetazepam also inhibited afterdischarges induced by electrical stimulation of the hippocampus and amygdala. These results indicate that lormetazepam has pharmacological properties characteristic of benzodiazepines and that the activity is more potent than those of diazepam, nitrazepam and flurazepam.

Anesthetics↗
PubMed1985

Differential effects of electroconvulsive shock on four models of experimentally-induced aggression in rats.

The effects of electroconvulsive shock (ECS) on the hyperemotionality and muricide in olfactory bulbectomized rats (OB rat) were compared with those in spontaneous killer rats (SP rat), raphe lesioned rats (Raphe rat) and delta 9-tetrahydrocannabinol treated rats (THC rat). Single and chronic treatment of ECS inhibited the muricide and attack response to a rod, but did not affect the struggle response to handling and flight response to air blowing. Muricide was markedly inhibited by ECS in OB and SP rats, and was moderately inhibited in THC rats, while it was slightly inhibited in Raphe rats. The present result indicates that muricide of OB rats is a useful model for evaluating antidepressant drugs as this behavior is markedly inhibited by ECS in OB rats. Furthermore, it is suggested that the effect of ECS on muricide is different depending upon the methods to induce muricide, although muricide itself seems to be behaviorally similar.

Aggression↗
PubMed1985

Role of the amygdala in the hippocampal kindling effect of rats.

In the present experiment, the role of the amygdala in the formation of the hippocampal kindling effect was investigated in rats with chronic electrode implants. The number of trials required for the establishment of hippocampal kindling was significantly shortened by either ipsilateral or bilateral amygdaloid lesions. The high amplitude spike waves in the frontal cortex and reticular formation appeared earlier in the amygdaloid lesioned rats than in the sham lesioned rats. It is suggested that the amygdala has an inhibitory effect on the development of the hippocampal kindling effect. On the other hand, either the ipsilateral or bilateral amygdaloid lesions after the establishment of hippocampal kindling inhibited the induction of generalized convulsion by hippocampal stimulation. Three and 8 repeated daily stimulations were needed to reestablish the hippocampal kindling effect after the ipsilateral and bilateral amygdaloid lesions, respectively. These results do not coincide with the above-mentioned results indicating that the amygdala has an inhibitory role in the formation of hippocampal kindling. It is suggested that the neuronal circuits involved in the formation of hippocampal kindling in the amygdaloid lesioned rats are different from those in the intact rats.

Amygdala↗
PubMed1984

The role of calcium ions in circadian rhythm of suprachiasmatic nucleus neuron activity in rat hypothalamic slices.

The role of calcium ions in maintaining the circadian rhythm of suprachiasmatic nucleus (SCN) neuron activity was investigated using rat hypothalamic slice preparations. In normal Krebs solution, the firing rate of SCN neurons was higher in the light period than in the dark period. In Ca2+-free Krebs solution, SCN neuron activity was low during all periods and did not show diurnal rhythm. These results suggest that the disappearance of circadian rhythmic change of SCN neuron activity in Ca2+-free Krebs solution may be due to the disappearance of synaptic transmission in the SCN.

Animals↗
PubMed1984

Influence of environmental light-dark cycle and enucleation on activity of suprachiasmatic neurons in slice preparations.

The influence of environmental light-dark cycle (LD) and bilateral enucleation on single neuronal activity in the suprachiasmatic nucleus (SCN) was examined using a hypothalamic slice preparation. Firstly, we reconfirmed previous results that the discharge rate in slices taken from animals kept on normal LD was higher during the light than during the dark period. Secondly, the day time discharge rate in the ventrolateral part of the SCN was decreased by bilateral enucleation and DD housing, while in the dorsomedial part it was unaffected. Thirdly, LL housing suppressed the discharge rates in both parts during the day and night periods. The present results suggest that the dorsomedial part of the SCN is more important in regulation of the circadian rhythm of SCN neuronal activity than the ventrolateral.

Animals↗
PubMed1984

Cardiovascular responses to centrally administered serotonin in conscious normotensive and spontaneously hypertensive rats.

Serotonin (5-HT, 1-10 micrograms), injected into the lateral ventricle of the urethanized, and conscious normotensive and spontaneously hypertensive rats produced a dose-dependent increase in blood pressure. In conscious rats, there was mainly a decrease in heart rate while variable changes in heart rate were elicited by intraventricular (i.c.v.) administration of 5-HT in anesthetized animals. These pressor responses and bradycardia caused by 5-HT in conscious rats were reduced by pretreatment with i.c.v. methysergide (25 micrograms). Microinjection of 5-HT (2.5-5 micrograms) directly into the medial hypothalamus and the anterior hypothalamus/preoptic area of conscious normotensive rats caused a pressor response accompanied by variable changes in heart rate. The present results indicate that urethane can affect the HR response to 5-HT injected i.c.v. without having a marked influence on the pressor response. These findings, which show that 5-HT produced a rise in BP independent of the anesthetized or conscious state and of normotension or hypertension, further confirm the idea that 5-HT plays a pressor role in the central regulation of the cardiovascular system.

Animals↗
PubMed1984

Effect of bilateral olfactory bulbectomy on discrimination avoidance conditioning in rats.

Studies were made with the two-way shuttle box method on the acquisition of discrimination avoidance learning by olfactory bulbectomized rats in relation to changes in emotional behavior. Bulbectomized rats showed a marked increase in locomotor activity, with accompanying augmentation of the reactivity and the appearance of muricidal behavior. Initially, the bulbectomized rats showed elevated conditioned avoidance responses to both the CS+ and the CS-. In later stages, there was a continued slow increase in responses to the CS+ accompanied by a decrease in responses to the CS-, until responses to both stimuli were only slightly elevated above the levels shown by control rats. This result suggests that olfactory bulbectomy does not affect discrimination ability itself, but the impairment of discrimination during the initial stages is resulted from hyperemotionality induced by olfactory bulbectomy.

Aggression↗
PubMed1984

Effects of chronic administration of antidepressants on mouse-killing behavior (muricide) in olfactory bulbectomized rats.

Two forms of drug administration, i.e., systemic subcutaneous administration and microinjection into the medial amygdala were employed to examine the effect of chronic administration of psychotropic drugs on muricide in olfactory bulbectomized rats. Muricide inhibition induced by the systemic doses of chlorpromazine (CPZ) 10 mg/kg and diazepam 10 mg/kg was reduced with chronic administration, while that by desipramine (DMI) 10 mg/kg and amitriptyline 30 mg/kg was augmented with chronic administration. Muricide inhibition induced by microinjection of CPZ was also reduced, while that by DMI was augmented. These results indicate that muricide by olfactory bulbectomized rats is a useful animal model for evaluating antidepressants and that a potential site of action of antidepressants is located in the medial amygdala.

Aggression↗
PubMed1984

Anti-muricide mechanisms of chlorpromazine and imipramine in OB rats: adrenoceptors and hypothalamic functions.

Chlorpromazine (CPZ) microinjected into the posterior part of the lateral hypothalamus (p-LH) and the lateral preoptic area (1-POA) of OB rats shows anti-muricide and cataleptogenic effects as well as a drowsy pattern in cortical EEG, while imipramine (IMP) injected into p-LH shows anti-muricide and cataleptogenic effects without change of cortical EEG. The present study examined the effects of drugs injected into p-LH and 1-POA on muricide, catalepsy and cortical and limbic EEG. CPZ (20, 50 micrograms) suppressed muricide and induced catalepsy and an EEG drowsy pattern in the two regions. The effects of CPZ in p-LH were similar to those of propranolol (PRO). In 1-POA, the anti-muricide effect of CPZ was similar to that of phenoxybenzamine, whereas the cataleptogenic and EEG effects were similar to those of PRO. IMP (10, 20 micrograms) in p-LH showed anti-muricide and cataleptogenic effects and induced a slight drowsy pattern in limbic EEG. The effects were similar to those of atropine. Lidocaine did not show any effects in the two regions. The cataleptogenic effects of CPZ and IMP did not appear related with the anti-muricide effects. The results suggest that the anti-muricide effect of CPZ in the hypothalamus depends on its adrenoceptor blockage, while that of IMP relates to its anticholinergic effect. In addition, beta-receptors in the hypothalamus appear related to the arousal system and dopaminergic functions.

Aggression↗
PubMed1984

Irritable aggression induced by delta 9-tetrahydrocannabinol in rats pretreated with 6-hydroxydopamine.

Administration of delta 9-tetrahydrocannabinol (THC) to grouped rats injected intraventricularly with 6-hydroxydopamine (6-OHDA) produced violent fighting accompanied by remarkable hyperirritability. This behavior was induced reproducibly from the 10th to 100th postoperative days. It was shown that this irritable aggression could be measured continuously and quantitatively in terms of degree of activity and/or vocalization using a newly designed analyzer. The effect of THC differed markedly from the action of apomorphine and methamphetamine in 6-OHDA pretreated rats. Apomorphine induced irritable aggression but not vigorous vocalization. On the other hand, methamphetamine induced much less irritable aggression than apomorphine-induced aggression. It is assumed that a THC-invoked imbalance in catecholamine agonistic and serotonin antagonistic action brought about by activation of supersensitized catecholaminergic receptor was operating to produce the aggression. Specifically, hypoactivity of serotonergic neurons might play a key role in the occurrence of THC-induced irritable aggression.

Aggression↗
PubMed1984

Electrophysiological studies of the development of suprachiasmatic neuronal activity in hypothalamic slice preparations.

The rate and pattern of neuronal discharge in the suprachiasmatic nucleus (SCN) during developmental stages were studied and compared with those of the ventromedial (VMH) and the lateral hypothalamus (LHA) using rat hypothalamic slices. The firing rate of the SCN neurons was low on the 7th and 11th days; however, it dramatically increased by the 14th day to reach the adult rate, while firing rates of VMH and LHA neurons increased gradually with age. The discharge rate of neurons in the ventrolateral part of the SCN (VL-SCN) was higher than that of the dorsomedial SCN (DM-SCN) neurons in 14-, 21- and 70-100-day-old rats. Activity of the DM-SCN neurons on day 21 were unaffected by bilateral enucleation on the third day, while activity in the VL-SCN decreased; that of both parts was significantly decreased by a constant light schedule.

Animals↗
PubMed1984

Field potentials in the suprachiasmatic nucleus of rat hypothalamic slice produced by optic nerve stimulation.

Spatial profile of a projection from retina to the suprachiasmatic nucleus (SCN) was studied by electrophysiological method. Stimulation of contralateral optic nerve evoked the fast positive and late large negative waves in only the ventrolateral but not the dorsolateral parts of the posterior SCN. This result, in agreement with anatomical evidence suggests that the late negative wave is due to excitatory synaptic potential in the SCN and has a role for elevating the neuronal activity in the ventrolateral part of the posterior SCN daytime.

Animals↗
PubMed1984

Behavioral effects of brotizolam, a new thienotriazolodiazepine derivative.

The behavioral effect of brotizolam was investigated in mice and rats, in comparison with those of diazepam, nitrazepam and estazolam. Locomotor activity of rats in an open field situation was slightly increased with smaller doses of brotizolam and estazolam and with larger doses of nitrazepam, while it was decreased with large doses of brotizolam and estazolam. The anticonflict effect of brotizolam in rats was approximately as potent as that of diazepam and was augmented following chronic administration for 10 days. In suppressing hyperemotionality and muricide of olfactory bulbectomized rats, brotizolam was more potent than diazepam, being approximately equipotent to nitrazepam and estazolam. Brotizolam, diazepam, nitrazepam and estazolam prevented both maximal electroshock and pentetrazol convulsions in mice, the effects on the latter being much more potent than those on the former. In impairing rotarod performance, brotizolam was as potent as estazolam and nitrazepam and was much more potent than diazepam in mice, but was less potent than estazolam and nitrazepam in rats. These results indicate that brotizolam possesses pharmacological properties characteristic to benzodiazepines and that the activity is more potent than that of diazepam and approximately as potent as those of nitrazepam and estazolam.

Aggression↗
PubMed1984

[The outcome of acute subdural hematoma].

Thirty-five cases of acute subdural hematoma (ASDH) were reviewed and divided into two groups of A and B according to the outcome. The findings of computed tomography (CT) and the time interval between head trauma and surgical intervention were investigated to know the factors that influence the prognosis in ASDH. Group A, 18 patients, had a poor outcome. Fifteen patients out of 18 had the removal of hematoma and decompression craniectomy with 10 deaths, 4 vegetative states and 1 severe disability. Three patients died without surgery. Group B, 17 patients, were treated surgically in the same way as in group A and all patients had a good recovery with 14 making a full recovery and 3 with a moderate disability. Surgical mortality was 31.3% and overall mortality was 37.1%. The features of the CT findings in 18 patients of group A were as follows. Eleven patients had midline shift of more than 15 mm, 9 had subdural high density area of more than 15 mm and 12 patients had bilateral collapse of the lateral ventricles. The characteristic finding of CT recognized in all patients of group A was disappearance of the ambient cistern. On the contrary, in 17 patients of group B the displacement of the intracranial structure was not so severe as in group A. The midline shift of 14 patients was less than 7.5 mm, the width of subdural high density area of 15 patients was less than 7.5 mm and the ambient cistern was recognized in 12 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1983

Development of the circadian rhythm of neuronal activity in suprachiasmatic nucleus of rat hypothalamic slices.

Development of the circadian rhythm of neuronal activity in the suprachiasmatic nucleus (SCN) was studied in rat hypothalamic slices. The firing rate of SCN neurons of 7- and 11-day-old rat pups was low during all of the day, whereas that of 14- and 21-day-old pups was high during daytime and low during nighttime. The present results suggest that the circadian rhythm of SCN neuronal activity is established between 11 and 14 days of age, corresponding closely to the time of onset of the other various hormonal and behavioral circadian rhythms.

Age Factors↗