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Biomedical subjects

G Nisticò

Publications and source records attributed to G Nisticò.

At least 109 records · Page 6Linked to original sources
PubMed1985

Cardiovascular effects of tetanus toxin after systemic and intraventricular administration in rats.

A single intraperitoneal injection of tetanus toxin (50,100 and 200 minimum lethal dose per rat) produced a significant and dose-dependent increase in systemic blood pressure and heart rate in conscious rats. On the contrary, tetanus toxin, given directly into the third cerebral ventricle (20 and 40 minimum lethal dose), produced a gradual and dose-dependent decrease in blood pressure accompanied by bradycardia. In conclusion, the present findings show that tetanus toxin is able to affect cardiovascular activity and it is suggested that this may be due to an interference with central GABAergic mechanisms.

Animals↗
PubMed1985

Behavioural and spectrum power effects of opioid peptides in chicks.

The effects of intracerebroventricular administration of beta-endorphin, dermorphin, D-ala2-methionine-enkephalinamide (DALA) and pentazocine, on behaviour, electrocortical activity and ECoG spectrum power in young chicks were studied. Beta-endorphin, dermorphin and DALA produced dose-dependent behavioural sedation and sleep accompanied by electrocortical high voltage slow wave activity and increase in total voltage power with a predominant increase in the lower bands of ECoG spectrum. Dermorphin was found significantly more potent than beta-endorphin and DALA since it was active at much lower doses. Behavioural and ECoG sleep evoked by opioid peptides were rapidly reversed by naloxone showing that these effects are mediated through an activation of specific opioid receptors. Doses of pentazocine equimolar with doses of dermorphin and beta-endorphin producing sleep did not affect behaviour and spectrum power whereas higher doses produced opposite effects, i.e., behavioural stimulation, pecking and increase in locomotor activity.

Animals↗
PubMed1985

gamma-Aminobutyric acid metabolism and behavioral effects after intraventricular injection of spermine in chicks.

Effects of intraventricularly injected spermine on behavior and electrocortical activity and gamma-aminobutyric acid (GABA) metabolism after a single dose of 1.13 mumol/animal were studied. Decrease in locomotor activity, sedation or sleep, and electrocortical synchronization that lasted approximately 2 h were observed. In addition spermine caused a significant increase in GABA content in diencephalon and brainstem, 30 min after administration. Concomitantly a significant increase of glutamate decarboxylase (GAD) activity was observed in cerebral hemispheres, diencephalon, and brainstem. Reduction in gamma-aminobutyrate: alpha-oxoglutarate amino-transferase (GABA-T) levels occurred in the diencephalon along with a significant increase of GABA-T in the brainstem. The present results demonstrate that spermine has the capacity to affect GABA metabolism and are in favor of the suggestion that endogenous polyamines may modulate GABAergic mechanisms.

4-Aminobutyrate Transaminase↗
PubMed1984

Long-lasting hypothermic effects of vincristine in rats.

The effects of vincristine given intravenously on deep and superficial body temperature were assessed in rats kept at ambient temperature within the thermoneutral range. Vincristine (0.5 and 1 mg/kg i.v.) produced a gradual but marked hypothermic response which was dose-dependent, reached its maximum after approximately 3 h and lasting approximately 48 h. Vincristine induced a decrease in deep body temperature which was accompanied by piloerection and a decrease in skin temperature. Pretreatment with phentolamine, an alpha-adrenoceptor blocking agent (0.5 mg/kg i.v. 15 min before) prevented the hypothermic effects induced by subsequent administration of vincristine (0.5 mg/kg i.v.). These experiments showed that vincristine produced a marked hypothermic response in rats. However, the precise site of action remains to be established.

Animals↗
PubMed1984

Behavioural and electrocortical spectrum power changes after intraventricular injection of patulin in rats.

The effects of patulin when given into the third cerebral ventricle of rats, on behaviour and electrocortical spectrum power have been investigated. Patulin (10 micrograms i.v.t.) produced behavioural sedation, hypoalgesia, tail rigidity, piloerection and postural changes. This symptomatology lasted approx. 3 h and was accompanied by slower frequency and larger amplitude potentials in the electrocorticogram (ECoG) and by an increase in total voltage power. A larger dose (50 micrograms) produced a more dramatic picture characterized by catatonic posture with kyphosis, loss of the righting reflex, tail rigidity and on a few occasions short-duration episodes of tonic-clonic convulsions. Such a symptomatology was accompanied by a flattening of ECoG activity with a significant fall in total voltage power, as well as in preselected bands (0-3, 3-6, 6-9, 9-12, and 12-16 Hz). A lower dose (1 microgram) of patulin, on the other hand, produced behavioural sedation without significant changes in ECoG spectrum power.

Animals↗
PubMed1984

Stimulation of crop sac and pituitary lactotrophs after intraventricular administration of dermorphin in pigeons.

The effects of dermorphin, a new potent opioid peptide, on structural and ultrastructural changes in the crop sac and in pituitary lactotrophs were assessed in pigeons (Columba livia). A single administration of dermorphin into the third cerebral ventricle (1 microgram) and the same dose repeated for 3 consecutive days both produced maximal crop sac stimulation, as documented by the presence of milk-like material as well as by scanning and transmission electron microscopy of crop sac mucosa. In addition, marked stimulatory effects were also observed in pituitary lactotrophs, as shown by stimulation of Golgi apparatus, enlargement of rough endoplasmic reticulum, increase in mitochondria size, and the presence of lysosomes and electron-opaque granules. The stimulatory effects of dermorphin on the crop sac and lactotrophs were completely prevented by naloxone, an antagonist at opiate receptors. Since dermorphin is a natural constituent of the avian brain, it has been suggested that this peptide may represent the still-obscure hypothalamic prolactin stimulatory factor.

Animals↗
PubMed1984

Lack of effects of thallium on GABAergic mechanisms in discrete areas of the rat brain.

The effects of intramuscular treatment for 3 and 5 consecutive days with thallium sulphate (2.5, 5 and 10 mg/Kg) on GABA content, glutamate - decarboxylase (GAD) and GABA-transaminase (GABA-T) activity in different areas of the rat brain were studied. Thallium at the dose levels used did not produce significant changes in GABA content, GAD and GABA-T activity in the brain hemispheres, brainstem, hypothalamus, diencephalon and caudate nucleus.

Animals↗
PubMed1984

Cardiovascular and respiratory effects of spermidine and spermine: an experimental study.

Spermidine (SPD) and spermine (SPM) produced in anaesthetized dogs significant cardiovascular changes at higher doses than other transmitters, i.e. l-noradrenaline, l-adrenaline, histamine, acetylcholine, which produce cardiovascular effects at doses of 0.01-0.05 micrograms/kg given intravenously. SPD was shown to be more active than SPM. The hypotensive response observed after i.v. injection is due to histamine release. The hypotensive and bradycardic effects observed after microinjection of SPD into III cerebral ventricle or into the vertebral artery and of SPM into the vertebral artery are due to an increase in parasympathetic output. Spermidine increased and spermine decreased the baroreceptor reactivity. SPD and SPM did not change the vascular beta- and alpha-adrenergic, cholinergic and histaminergic receptor reactivity.

Animals↗
PubMed1984

Effects of tetanus toxin after intracerebral microinjection are antagonized by drugs enhancing GABAergic transmission in adult fowls.

In adult fowls (Gallus domesticus), the behavioural effects of small doses of tetanus toxin, after unilateral microinjection into the nucleus mesencephalicus profundus (NMP), homologous to the mammalian substantia nigra, were studied. A rich pattern of stereotyped movements, vocalization, ipsilateral head-neck rotation, wing abduction, occasional ipsilateral circling and escape responses from the box were observed; the intensity of such symptomatology was dose-related and fully reversible within approx. 4 hr. Pretreatment with sodium valproate (100 and 200 mg/kg, i.m.) or with ethanolamine-sulphate (EOS, 1.6 mumol into the NMP) completely prevented the effects of tetanus toxin. The present findings show that fowls can represent an ideal species for studying acute central effects of tetanus toxin and more interestingly that drugs enhancing GABAergic mechanisms are able to prevent the effects of tetanus toxin.

Animals↗
PubMed1984

Cardiovascular effects of putrescine in dogs after systemic, intra-arterial vertebral and intraventricular injection.

Putrescine produced in anesthetized dogs significant cardiovascular changes at higher doses than other transmitters. The hypotensive response observed after intravenous injection is due to histamine release. Tachycardic effects seem to be due both to release of histamine and to a reflex stimulation of carotid-sinus baroreceptors. The hypotensive and bradycardic effects observed after microinjection of putrescine into the III cerebral ventricle or into the vertebral artery are due to an increase in parasympathetic output.

Animals↗
PubMed1982

Effects of apomorphine on glutamate decarboxylase activity in chick paleostriatum augmentatum.

In young chicks the effects of two different doses of apomorphine, a small dose, producing behavioural and electrocortical sleep and a larger one producing arousal, on GABA content, GAD and GABA-T activities in the paleostriatum augmentatum were studied. The small dose of apomorphine did not affect GABAergic mechanisms in this area, whereas the dose producing behavioural and electrocortical arousal significantly increased GAD activity and GABA content. The results of the present experiments are in favour of an interaction between dopaminergic and GABAergic mechanisms in the avian paleostriatum augmentatum.

Animals↗