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Biomedical subjects

G Nisticò

Publications and source records attributed to G Nisticò.

At least 127 records · Page 7Linked to original sources
PubMed1981

Behavioral and electrocortical effects of beta-endorphin after intracerebral infusion in rats.

In rats with cannulae chronically implanted into specific areas of the brain, the effects of beta-endorphin were studied on behavior and electrocortical activity. It has been shown that analgesia and catatonia were evoked after infusing beta-endorphin into the III cerebral ventricle or into the hypothalamus. On the contrary, beta-endorphin microinjected into the caudate nucleus or into the substantia nigra produced an intense pattern of stereotyped movements, occasional contralateral circling, contralateral myoclonic jerks and asymmetric posture. Stereotyped gnawing, grooming and "wet-dog" syndrome preceded catatonia after intrahypothalamic administration of beta-endorphin. Bilateral (III ventricle) or ipsilateral (hypothalamus, caudate nucleus and substantia nigra) high voltage electrocortical spikes and other ECoG pathological changes accompanied by motor disorders (stereotypies, myoclonic jerks) or without any overt behavioral change were constantly observed. Behavioral and electrocortical changes evoked by beta-endorphin were long-lasting and rapidly reversed by the specific opiate antagonist, naloxone.

Animals↗
PubMed1981

Behavioural and body temperature effects of meningococcal lipopolysaccharide after intraventricular injection in adult fowls Gallus domesticus.

The effects of the meningococcal lipopolysaccharide (LPS), given into the II cerebral ventricle of adult fowls, were studied on behaviour and body temperature. Immediately after the administration a marked and dose- dependent behavioural sedation or sleep lasting over 2 hours or more according to the dose was observed. The body temperature effects of LPS were biphasic, i.e. and immediate initial phase of hypothermia lasting about 100 min, followed by a longer-lasting fever response. A pretreatment with phentolamine, an antagonist at alpha-adrenoceptors prevented the hypothermic phase following the endotoxin administration. In conclusion, present experiments show that in comparison to 0-somatic antigen of Shigella dysenteriae, meningococcal endotoxin possesses more marked behavioural effects and a different profile in body temperature effects.

Animals↗
PubMed1981

Evidence for the existence of a dopamine-sensitive adenylate cyclase in chick optic tectum.

The effects of several concentrations of dopamine on chick optic tectum adenylate cyclase were studied. Dopamine produced a dose-dependent increase in the intracellular content of c-AMP. These effects were specifically antagonized by haloperidol and chlorpromazine, whereas antagonists at alpha-and beta-adrenoceptors were significantly less effective. In conclusion, the present experiments provide evidence for the existence within the avian optic tectum of a dopamine-sensitive adenylate cyclase activity.

Adenylyl Cyclases↗
PubMed1980

Enhanced behavioural, electrocortical and hyperthermic effects of serotonin-like agents after impairment of serotonin transmission in fowl brain.

In adult fowls and in young chicks (Gallus domesticus) the effects were studied on body temperature, behaviour and electrocortical activity of 5-HT and other direct or indirect serotonin agonists given into the III cerebral ventricle in conditions of prolonged impairment of serotoninergic transmission. In chicks pretreated with 5,6-dihydroxytryptamine the subsequent intraventricular injection of 5-HT produced more intense and longer-lasting hyperthermic response and behavioural and electrocortical sleep. On the other hand fenfluramine given intraventricularly in fowls pretreated with 5,6-DHT did not produce significant body temperature and behavioural changes. After 14 and 21 day treatment with methysergide the subsequent administration of 5-HT, fenfluramine and quipazine produced in fowls an hyperthermic response and behavioural sleep more marked and longer-lasting than in control animals. The present experiments show that in conditions of chronic impairment of 5-HT function there is an enhanced behavioural and body temperature response to 5-HT and drugs acting by releasing endogenous 5-HT or 5-HT agonists.

5,6-Dihydroxytryptamine↗
PubMed1980

Cefazolin: a valid model of experimental epilepsy?

In various animal species (chicks, rats and rabbits) the intravenous injection of high doses of cefazolin, a cephalosporin not hitherto reported to produce epileptic seizures, was found to produce epileptiform electrocortrical changes similar to those evoked by intravenous benzylpenicillin. Similar phenomena as those reported after systemic injection were also observed after microinjection of cefazolin into the III cerebral ventricle. In fact, both in chicks and rats cefazolin given by the latter route produced wild running crisis, myoclonic jerks of the limbs and in some instances generalized clonic convulsions. Concomitantly, bilateral electrocortical high voltage bursts of spikes were observed, followed during the intercritic period by periodic bilateral or unilateral single spikes.

Animals↗
PubMed1980

Effects of intraventricular gamma-acetylenic-GABA on GABA concentrations, GABA-T and GAD in several areas of the chick brain.

The great interest in new compounds able to increase GABA concentration in the brain as potential antiepileptic drugs has led to the synthesis of powerful inhibitors of GABA transaminase (GABA-T) e.g. gamma-acetylenic GABA (GAG) and gamma-vinyl-GABA. Present experiments were aimed to study behavioral, electrocortical and biochemical effects of GAG after its intraventricular injection. It has been shown that in chicks the microinjection of GAG into the third cerebral ventricle produced a biphasic behavioral and electrocortical syndrome : an initial phase of behavioral and electrocortical sleep followed by a paradoxycal increase in motor activity and a very intense behavioral and ECoG arousal pattern. In addition intraventricular GAG (0.8 mumol) produced a significant increase 1 and 2 h later in GABA concentration in the diencephalon and brain-stem whereas no changes occurred in other brain areas e.g. cerebral hemispheres, optic lobes. Higher doses (1.6 mumol), produced after 1 h, concomitantly to the increased GABA concentration, a significant GABA-T inhibition and a profound inhibition of glutamate-decarboxylase in the diencephalon and brain-stem. Present experiments may explain the paradoxical behavioral, motor and electrocortical stimulation observed at the time of GABA increase concentration and suggest that a small functional neuronal pool of GABA, more than the whole absolute levels of GABA in a given area of the brain, seems to be involved in the control of GABAergic mediated inhibitory mechanisms.

4-Aminobutyrate Transaminase↗
PubMed1980

Central effects of histamine and H1 and H2 receptors agonists and antagonists after intraventricular infusion in fowls.

In adult fowls (Gallus deomesticus) the effects of histamine H2 and H2 histamine receptors angonists and antagonists infused into the III cerebral ventricle were studied on behaviour, electrocortical activity and body temperature. Histamine produced biphasic effects, i.e. an initial period of electrocortical synchronization was followed by a longer-lasting behavioural stimulation, electrocortical desynchronization and shivering. Body temperature was increased in a dose-dependent manner. Dimaprit, an agonist at H2 receptors, produced behavioural and electrocortical sleep and decreased body temperature whereas, 2-(2-thiazolyl-)-ethyl-amine, an agonist at H1 receptors, behavioural stimulation, electrocortical desynchronization, vocalization and hyperthermia. Cimetidine, an antagonist at H2 receptors, produced intense behavioural stimulation and electrocortical desynchronization accompanied by vocalization, tachypnoea, occasional escape responses and stereotypies. Body temperature was increased. Mepyramine, an antagonist at H1 receptors, produced behavioural and electrocortical sleep and prevented behavioural excitation elicited by subsequent infusion of histamine and hyperthermia evoked by 2-(2-thiazolyl -ethylamine. Haloperidol, a neuroleptic drug, sharing with mepyramine membrane stabilizing properties, was unable to antagonize histamine-induced behavioural excitation. In conclusion, present experiments provide pharmacological evidence for the existence of H1 and H2 histamine receptors in avian brain and suggest an involvement of histamine H1 and H2 receptors in the control of arousal-sleep and thermoregulatory mechanisms.

Animals↗
PubMed1979

Antagonism of prostaglandin E1 and E2 fever by catecholamines.

Antagonism of PGE1 and PGE2 fever by catecholamines in adult fowls was studied by infusing these substances into the brain. PGE1 and PGE2, given into the third cerebral ventricle or into the hypothalamus, produced an immediate, intense and long-lasting increase in body temperature. Noradrenaline and alpha-methylnoradrenaline infused into the hypothalamus or into the third cerebral ventricle during the fever peak were able to antagonize it and to revert the hyperthermic effect into an hypothermic effect. The possible modes of action of PG's and relations with catecholaminergic neurons in the hypothalamus are discussed.

Animals↗
PubMed1979

Light-evoked changes in chick optic lobe GABA system.

In young chicks the effects of 3 min stroboscope stimulation on GABA and free glutamic acid content and on GAD and GABA-T activity in optic lobes were studied. A significant depletion in GABA and glutamic acid levels was found to occur. In addition a sustained increase in GABA-T and GAD activity was observed. In conclusion present experiments are in favour of an inhibitory role played by GABA in chick optic tectum during stroboscope stimulation.

4-Aminobutyrate Transaminase↗
PubMed1979

Effects of intraventricular beta-endorphin on GABA system in some areas of chick brain.

In chicks with cannulae chronically implanted into the III cerebral ventricle, the effects of a single dose (10 micrograms) of beta-endorphin on GABA and free glutamic acid content, GAD and GABA-T activities in the diencephalon, brain-stem and brain hemispheres were studied at the time of maximal behavioural stuporous state and analgesia. A significant decrease in GABA concentration both in the diencephalon and brain-stem, accompanied by a significant increase in GABA-T activity in the same areas, was shown to occur. No changes were observed in GAD activity and in glutamic acid content in the studied areas of the brain. In conclusion, present experiments suggest that some central effects of a beta-endorphin may be due to an interference with GABA-ergic transmission.

4-Aminobutyrate Transaminase↗