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Biomedical subjects

S Ueki

Publications and source records attributed to S Ueki.

At least 163 records · Page 9Linked to original sources
PubMed1983

Inhibitory and excitatory effects of histamine on suprachiasmatic neurons in rat hypothalamic slice preparation.

The effects of histamine (HA) and serotonin (5-HT) on single neurons of the suprachiasmatic nucleus (SCN) in hypothalamic slices were investigated by iontophoretic application. Sixty-two of 181 cells were inhibited by HA, whereas 30 were excited. Forty-nine of 163 cells were inhibited by 5-HT, whereas 9 were excited. Pyrilamine, an H1-antagonist, slightly (2/7), and cimetidine, an H2-antagonist, strongly (10/13) antagonized the inhibitory effect of HA. The excitatory effect of HA was not antagonized by cimetidine (0/4), but was perfectly antagonized by pyrilamine (5/5). The present results suggest that HA and 5-HT play mainly an inhibitory role in the SCN neuronal activity, and that inhibition and excitation induced by HA may be mediated by H2- and H1-receptors, respectively.

Animals↗
PubMed1983

Different effects of amino acids, acetylcholine and monoamines on neuronal activity of suprachiasmatic nucleus in rat pups and adults.

A study was undertaken of the effects of iontophoretically applied amino acids, acetylcholine and monoamines on suprachiasmatic nucleus (SCN) neurons of rat pups, at the 11th postnatal day, using a hypothalamic slice preparation. GABA and taurine inhibited 97 and 42% of SCN neurons, respectively, while glycine had no effect. Glutamate excited 68% of them. These effects were similar to those in adult rats. Serotonin and noradrenaline inhibited 6 and 10% of SCN neurons, respectively, in rat pups, whereas 32 and 26% of them were inhibited in adult rats. Acetylcholine excited 7% but inhibited 26% of SCN neurons in rat pups and these values were almost the same as those of adult rats. These results reveal that acetylcholine and amino acids regulate SCN neurons even in rat pups, whereas monoamines play an important regulatory role in SCN activity in adult rats only.

Acetylcholine↗
PubMed1983

Increase in muscarinic acetylcholine receptors in mouse intestine by hexamethonium treatment.

The effects of hexamethonium (C6) administration on muscarinic acetylcholine receptors (mACh-R) in the intestine and brain of mice were investigated. Mice were treated with C6 with an osmotic mini-pump (330 mg/kg/day) for one week and then the binding of 3H-quinuclidinylbenzilate (3H-QNB) in the intestine and brain were assayed. This treatment increased the maximum specific binding (Bmax) of 3H-QNB from 160 to 320 fmoles/mg protein in the ileum and from 190 to 340 fmoles/mg protein in the rectum, without affecting the KD values in these regions. On the contrary, C6 treatment did not change the Bmax or KD value in brain tissues. This C6 treatment increased the sensitivity of the contractile response of the intestine to muscarinic agonists, possibly by increasing mACh-R.

Animals↗
PubMed1983

Methamphetamine mortality to emotional stimuli administered in the form of affective communication.

Methamphetamine induced mortality in physically stressed and non-physically stressed mice was investigated by employing a communication box in which shocked mice communicated their distress to unshocked mice in neighboring boxes. Intraperitoneal administration of methamphetamine 30 mg/kg caused greater mortality in both the shocked "sender" mice and the unshocked "responder" mice than in control when maintained at 27 +/- 1 degree C. Forty-eight hours after injection, the "sender", "responder" and control mice showed mortality of 80, 60 and 10%, respectively. This result indicates that the mortality of methamphetamine may be potentiated not only by physical stress but also by non-physical stress.

Animal Communication↗
PubMed1983

Effects of restricted feeding on single neuron activity of suprachiasmatic neurons in rat hypothalamic slice preparation.

Influence of restricted feeding on single neuron activity in the rat suprachiasmatic nucleus (SCN) was examined using hypothalamic slice preparations. Feeding restriction for one month did not change SCN neuron activity in either normal light-dark schedule (LD) or constant light schedule (LL). Locomotor activity in vivo was increased for a few hours before and during feeding time by food restriction of both LD and LL rats. The present experiment suggested that the memory of feeding time produced by food restriction is independent of SCN neuron activity.

Animals↗
PubMed1983

Autonomic drug effects and gastric secretion in a new experimental model of stress ulcers in rats.

A psychological procedure which does not involve the application of physical stimulation was used to produce gastric ulcers experimentally. Ulceration was induced in rats by exposing the animals to the aggressive attacks of rats treated with 6-hydroxy-dopamine (6-OHDA). Gastric secretion and the effects of autonomic drugs on ulcer formation were investigated. Atropine methylbromide did not significantly inhibit the occurrence of erosions. Phentolamine or hexamethonium bromide significantly inhibited the production of erosions, and combined administration of an anticholinergic agents and alpha-blocking agent led to a complete inhibition, with no notable behavioral change. In case of pylorus ligation, gastric secretion during exposure to attack of 6-OHDA-treated rats was significantly less than that in the controls. We suggest that the sympathetic nervous system plays an important role in the production of gastric erosions, as induced by the methods reported in this study.

Animals↗
PubMed1983

Attack stress and IgE antibody production in rats.

The effect of stress on production of immunoglobulin E (IgE) in rats was investigated, the IgE being titrated by passive cutaneous anaphylaxis (PCA) reactions. In rats, exposed to attack by other rats made aggressive by intraventricular injections of 6-OHDA for one hour per day for three consecutive days before the first immunization, there was no difference in the titer of IgE as compared to the control rats, but, in the rats exposed to stress procedure before the second immunization, the production of IgE was significantly suppressed.

Adrenal Glands↗
PubMed1983

Effects of adrenergic blockers on the inhibition of muricide by desipramine and noradrenaline injected into the amygdala in olfactory bulbectomized rats.

Muricide in olfactory bulbectomized rats (OB rats) is readily inhibited by systemic administration of desipramine (DMI) or microinjection of DMI and noradrenaline (NA) into the medial amygdaloid nucleus. The present experiment investigated whether the muricide inhibition produced by these forms of drug treatment was mediated by alpha- or beta-noradrenergic receptors in the central nervous system. Muricide inhibition produced by systemic administration of DMI was antagonized by an alpha-blocker phenoxybenzamine but unaffected by a beta-blocker sotalol, although administration of these adrenergic blockers alone had no effect on muricide. Muricide inhibition induced by the microinjection of DMI and NA into the medial amygdaloid nucleus was similarly antagonized by pretreatment of phenoxybenzamine injected into the same site, but sotalol had no effect. Injection of phenoxybenzamine or sotalol alone into the medial amygdaloid nucleus did not elicit any changes in muricide. These findings suggest that mechanisms mediated by brain noradrenergic alpha-receptor play an important role in muricide inhibition by tricyclic antidepressants in rats and that the medial amygdaloid nucleus is an important site of action of these drugs.

Adrenergic alpha-Antagonists↗
PubMed1983

Effects of psychotropic drugs microinjected into the hypothalamus on muricide, catalepsy and cortical EEG in OB rats.

In order to elucidate the mechanism of anti-muricide action of psychotropic drugs in the brain, the present study examined influences of these drugs microinjected into the hypothalamus on muricide. Inhibition of muricide by chlorpromazine (CPZ) was found both in the lateral preoptic area (1-POA) and the posterior part of the lateral hypothalamus (p-LH), and that by chlordiazepoxide was seen only the mammillary body. These effects were accompanied by a drowsiness of cortical EEG. Anti-muricide action of tricyclic antidepressants was found in p-LH. The effect was not accompanied by EEG drowsiness. Effects of atropine injected into the hypothalamus on muricide and cortical EEG were similar to those of the antidepressants. Norepinephrine and serotonin did not show selective muricide-suppression. Although either CPZ in 1-POA and p-LH or the antidepressants in p-LH showed cataleptogenic effect, these effects did not appear related to anti-muricide action. The relationship between the anti-muricide action of psychotropic drugs and the physiological functions of the brain was discussed in comparison with these systemic administrations.

Aggression↗
PubMed1983

Characteristics of aggressive behavior induced by nucleus accumbens septi lesions in rats.

The effect of selective caudal and/or rostral nucleus accumbens septi lesions on emotional behavior were studied in male Wistar King A rats. The caudal, rostral, and both areas of the accumbens nuclei were lesioned each in separate animal groups. The rats of all groups exhibited hyperirritability and muricide after accumbens lesions. Muricide was highest in incidence in the group of both caudal and rostral accumbens lesions and remained unchanged throughout the experimental period of 15 days. Moreover, accumbens-lesioned rats also showed mouse-eating behavior. These results suggest that the accumbens plays an important role in modulating aggression, and the characteristics of aggressive behavior induced by accumbens lesions resemble that of raphe-lesioned rats.

Aggression↗
PubMed1983

Serum and erythrocyte acetylcholine esterase in Hirschsprung's disease.

Determination of acetylcholine esterase in serum (S-AChE) and erythrocytes (E-AChE) was carried out in nine patients with Hirschsprung's disease and 16 normal controls. S-AChE was significantly elevated in patients with Hirschsprung's disease, while no significant difference was observed in E-AChE in these two groups. In 17 patients with Hirschsprung's disease, S-AChE and E-AChE were determined after definitive operation. Twelve of these patients underwent a Duhamel type procedure in which a small part of the aganglionic bowel segment remained unresected. Five patients were treated by Swenson's procedure performing complete resection of the aganglionic bowel segment. S-AChE in patients treated by the Duhamel type procedure remained elevated, while it was as low as that in normal controls in patients who underwent Swenson's procedure. There was no significance in E-AChE in both groups. This study suggests a close relation of the level of S-AChE to the extent of the aganglionic bowel segment in Hirschsprung's disease.

Acetylcholinesterase↗
PubMed1983

Effects of reserpine, alpha-methyl-p-tyrosine, p-chlorophenylalanine and 5,7-dihydroxytryptamine on the hippocampal kindling effect in rats.

The role of the brain monoamines in the development of hippocampal kindling was studied. Reserpine markedly facilitated the formation of hippocampal kindling. The high amplitude spike waves in the amygdala and reticular formation appeared earlier in the reserpine treated rats than in the saline injected rats. alpha-Methyl-p-tyrosine did not have any effect on the formation of hippocampal kindling. Systemic injection of p-chlorophenylalanine and intraventricular injection of 5,7-dihydroxytryptamine also did not have any effect on the formation of hippocampal kindling. Progressive changes of afterdischarge elicited by hippocampal stimulation in the alpha-methyl-p-tyrosine, p-chlorophenylalanine and 5,7-dihydroxytryptamine treated rats are the same as those in the saline injected rats. These results indicate that the decrease in both catecholamines and serotonin levels caused a marked facilitation of the hippocampal kindling formation, but the separate decrease in either catecholamines or serotonin did not produce a significant effect.

5,7-Dihydroxytryptamine↗
PubMed1983

Effect of amino acids and monoamines on the neuronal activity of suprachiasmatic nucleus in hypothalamic slice preparations.

Influences of amino acids and monoamines on the single unit discharges of the suprachiasmatic nucleus (SCN) were investigated using hypothalamic slice preparations. Iontophoretic application of GABA inhibited 90% and taurine inhibited 40% of SCN neurons, while glycine inhibited only 4%. L-glutamate excited about 50% of the neurons. Serotonin, noradrenaline and dopamine inhibited 30, 22 and 26% of the SCN neurons, respectively. Amino acid effects were observed equally in both the ventrolateral part of the SCN and the remaining part of it, while monoamine effects were observed preferentially in the ventrolateral part of the SCN where the optic fibers and serotonin nerves terminated. These results suggest that amino acids and monoamines modulate the neuronal activity of the SCN through their direct effects.

Amino Acids↗
PubMed1983

Effect of zotepine on head-twitch induced by L-5-hydroxytryptophan, mescaline and 2,5-dimethoxy-4-methylamphetamine in mice and rats.

The effect of zotepine, a new neuroleptic, on head-twitch induced by L-5-hydroxytryptophan (L-5HTP), mescaline and 2,5-dimethoxy-4-methylamphetamine (DOM) in mice and rats was compared with that of known neuroleptics and the serotonin receptor blocker cyproheptadine. Among the neuroleptics tested, zotepine and haloperidol produced potent inhibitory effects on head-twitch induced by these three drugs. The results indicate that zotepine has a potent anti-hallucinogenic effect.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1983

The role of noradrenergic and serotonergic systems in the hippocampal kindling effect.

The role of the noradrenergic and the serotonergic systems in the development of hippocampal and amygdaloid kindling was studied. Dorsal noradrenaline bundle lesions markedly facilitated the formation of hippocampal and amygdaloid kindling. The most significant facilitation was observed in the earliest phase of kindling. Cortical noradrenaline content decreased by about 70% after dorsal noradrenaline bundle lesions. Midbrain raphe nuclei (both dorsal and medial raphe nuclei) lesions did not have any effect on the formation of both hippocampal and amygdaloid kindling. These results indicate that the dorsal noradrenaline bundle system plays an inhibitory role in the development of the seizure discharges and the behavioral convulsions in hippocampal and amygdaloid kindling.

Amygdala↗
PubMed1983

[Behavioral effects of ethyl loflazepate and its metabolites].

The behavioral effects of ethyl loflazepate and its metabolites were investigated in mice and rats, and they were compared with those of diazepam, nitrazepam and lorazepam. Locomotor activity of rats in open-field situation was increased with a wide range of doses of ethyl loflazepate and with large doses of nitrazepam. The anticonflict effect of ethyl loflazepate was slightly more potent than that of diazepam and much more potent than that of lorazepam. In suppressing muricide of both olfactory bulbectomized and raphe lesioned rats, ethyl loflazepate was approximately as potent as diazepam and much less potent than nitrazepam and lorazepam. Ethyl loflazepate was more potent than diazepam, nitrazepam and lorazepam in preventing pentetrazol-induced convulsion. In potentiating thiopental anesthesia in mice and impairing rotarod performance in mice and rats, ethyl loflazepate was less potent than diazepam, nitrazepam and lorazepam. The pharmacological activities of CM6913 and CM7116, metabolites of ethyl loflazepate, were approximately as potent as that of ethyl loflazepate. The duration of action of ethyl loflazepate was longer than those of the metabolites. These results indicate that ethyl loflazepate possesses pharmacological properties characteristic to benzodiazepines, and it is approximately equal to diazepam in potency and has a longer duration of action than diazepam, nitrazepam and lorazepam.

Aggression↗