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Biomedical subjects

P Preziosi

Publications and source records attributed to P Preziosi.

At least 235 records · Page 13Linked to original sources
PubMed1977

Lack of hypertensive and hyperglycemic effect of diazoxide after intraventricular injection.

In adult fowls intravenous but not intraventricular injection of diazoxide produced hypotension and a rise in blood glucose concentration. Since noradrenaline microinfused into the hypothalamus produced a fall in blood pressure, it does not seem that hypotensive effects of diazoxide are mediated through release of noradrenaline in areas of the luain accessible from the ventriculus tertius cerebri. Present experiments also indicate that the hyperglycemic effects of diazoxide is unlikely to be due to an action on central adrenergic receptors.

Animals↗
PubMed1977

Increased plasma corticosterone and decreased plasma thyroid-stimulating hormone levels in rats treated with vincristine.

A single i.p. injection of vincristine (1000 microgram/kg) into rats increased the plasma concentration of corticosterone after a latent period of 4 hr; the effect lasted for 48 hr. The response was dose related with the threshold dose being 100 microgram/kg and the maximal effect occurring after 250 microgram/kg. Vincristine also increased plasma corticosterone levels in hypophysectomized rats, suggesting that the drug may have a direct action on the adrenal gland. The injection of 500 or 1000 microgram/kg also reduced the plasma concentration of thyroid-stimulating hormone. Twelve and 18 hr after the injection of vincristine (1000 microgram/kg), the plasma concentration of thyroid-stimulating hormone was reduced, whereas the hypothalamic content of norepinephrine, a neurotransmitter involved in the regulation of thyrotropin-releasing hormone-thyroid-stimulating hormone secretion, remained unchanged. The adrenocortical stimulation produced by vincristine may play some role in the antineoplastic effects of this drug.

Adrenal Cortex↗
PubMed1976

Behavioural, electrocortical and body temperature effects of cholera toxin.

In young chicks intrahypothalamic infusion of cholera toxin produced a dramatic and dose-dependent increase in motor activity. Similar effects were also obtained in adult fowls after injection of cholera toxin into the third cerebral ventricle, the hypothalamus or the paleostriatum augmentatum. Electrocortical changes consisted of a slight desynchronization during the hypermotor activity and were preceded, when the highest intraventricular doses were used, by a short period of slower frequency and higher amplitude potentials. Intraventricular and intrahypothalamic but not intrastriatal injection of cholera toxin produced a typical biphasic hyperthermic response.

Animals↗
PubMed1976

Chronic treatment with reserpine and adrenocortical activation.

Daily i.p. injection of reserpine for 9 days strongly depletes hypothalamic norephinephrine (NE); after an initial activation, adrenocortical function returns to control values by the 5th day. Tyrosine hydroxylase (TH) activity in the brain stem of reserpine-treated rats exhibits a progressive increase. Alpha-methyl-para-tyrosine (chi-MpT) in rats chronically pretreated with reserpine provokes adrenocortical activation and a further decrease of hypothalamic NE. Exogenous ACTH in the same animals revealed an unimpaired adrenocortical reactivity after prolonged treatment with reserpine. These results seem to suggest that the disappearance of adrenocortical activation following long-term treatment with reserpine is due to the stimulated formation of a small functional pool of NE available for the tonic inhibition of CRF-ACTH secretion.

Adrenal Cortex↗
PubMed1976

Intraventricular antipyretics and bacterial pyrogen fever.

In adult fowls with cannulae chronically implanted into the IIIrd cerebral ventricle or into the hypothalamus, the effects of various hydrosoluble antipyretics, given intraventricularly, on bacterial pyrogen fever were studied. It has been shown that fever evoked by intrahypothalamic or intraventricular infusion of O somatic antigen of Shigella Dysenteriae was reduced by intraventricular administration of acetylsalicylate-lysine, indomethacin-methylglucamine or ibuprofen-lysine given during the febrile plateau. However, a 3-day intraventricular pretreatment with acetylsalicylate or indomethacin, or a single administration 30 min before, did not prevent fever by subsequent intraventricular or intrahypothalamic injection of pyrogen. On the contrary, intraventricular infusion of indomethacin or acetylsalicylate substantially reduced pyrogen fever when given after pyrogen latency period, e.g. just at the beginning of the febrile response. A possible involvement of E prostaglandins as mediator to pyrogen fever is discussed.

Analgesics↗
PubMed1976

Acute central effects of 5,6-dihydroxytryptamine in fowl.

In adult hens (Gallus domesticus) infusion into the IIIrd cerebral ventricle of 5,6-DHT (50, 75 and 100 mug) produced, after 5-10 min behavioural and electrocortical sedation and sleep lasting about 6-8 hr,and a monophasic or biphasic increase in body temperature for about 8 hr, Two and a half hr after 5,6-DHT administration, the histochemical picture showed a sustained decrease in yellow and green fluorescence in areas adjacent to the IIIrd ventricle, in the anterior hypothalamus and in the preoptic area, whereas no significant changes were detected in fluorescence of the tegmental cell-bodies. The present experiments suggest that behavioural and electrocortical effects evoked by 5,6-DHT seem to be due to a synergistic action of 5-HT and catecholamines displaced and released by this compound, whereas hyperthermic effects seem to be due to a more sustained release of 5-HT and/or to a direct action on 5-HT receptors and/or inhibition of 5-HT reuptake.

5,6-Dihydroxytryptamine↗
PubMed1975

Time-course of the effect of alpha-methyl-p-tyrosine on ACTH secretion.

250 mg/kg i.p. of the methyl ester of alpha-methyl-p-tyrosine (alpha-MpT) produced a rapid increase (by 1 h) in immunoreactive plasma ACTH, whereas the hypothalamic norepinephrine (NE) concentration and plasma corticosterone (B) changed significantly only 6 h after the administration of the inhibitor. These data suggest that the norepinephrinergic inhibitory tonus of CRF-ACTH secretion depends on the availability of a rapidly utilized pool of transmitter, affected in a very short time by alpha-MpT.

Adrenocorticotropic Hormone↗
PubMed1975

Double-blind study of a total liver extract in patients with hepatic dysfunction.

Forty hospitalized male patients with hepatic functional deficit were treated i.m. for 3 weeks with a total liver extract or placebo. The study was a double-blind. Statistical analysis (Student's t test, analysis of variance. Mann-Whitney test and Fisher's probability test) showed that liver extract therapy was more effective than placebo in improving liver function as indicated by changes in clinical features(digestive disorders, constipation, hepatomegaly) and colloidal and other laboratory tests, e.g. plasma cholesterol, prothrombin time, red cell count and hemoglobin concentration. An overall clinical assessment showed that 60% of patients treated with the liver extract were improved. In addition, no local or general side effects were observed. Present results are in favour of an hepatoprotective activity of a total liver extract.

Adult↗