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Biomedical subjects

G Peruzzi

Publications and source records attributed to G Peruzzi.

At least 73 records · Page 4Linked to original sources
PubMed1983

Early postnatal chlordiazepoxide administration: permanent behavioural effects in the mature rat and possible involvement of the GABA-benzodiazepine system.

The long term behavioural and biochemical effects of chronic chlordiazepoxide treatment during the period of neuronal maturation in the rat have been investigated. The administration to lactating mothers of chlordiazepoxide at very low doses (0.22 and 2.6 mg/kg) in their drinking water affects both behavioural and biochemical parameters in offspring at 60 days of age and undrugged since weaning. A deficit in the acquisition of the conditioned avoidance response in treated rats was observed, although no significant difference in spontaneous locomotor activity between control and treated rats was found. 3H-Flunitrazepam binding sites in cerebral cortex and hippocampus were decreased by the treatment, whereas no change was detected in cerebellum. Moreover, 3H-muscimol binding sites increased in hippocampus with no changes in cerebral cortex and cerebellum. According to the different regional distribution of benzodiazepine type 1 and type 2 receptors, we suggest that type 2 receptors are selectively affected by the treatment, and that the GABAergic receptor system is also permanently altered by administration of chlordiazepoxide during early postnatal life.

Animals↗
PubMed1983

Different patterns of respiratory reflexes originating in exercising muscle.

In anesthetized rabbits, rhythmic contractions of the gastrocnemius muscle elicited by stimulating the gastrocnemius nerves (40 trains/min of 0.5-ms rectangular pulses at 2.0-2.5 mult of motor threshold), increased pulmonary ventilation by increasing frequency (f). Expiratory duration (TE) was greatly reduced, while inspiratory time (TI) was much less changed. Mean expiratory flow (VT/TE) was increased consistently more than mean inspiratory flow (VT/TI). Arterial pressure (Pa) and heart rate (HR) were decreased. During tetanic contractions (100 Hz, 2.0-2.5 X T) tidal volume (VT) increased considerably more and f considerably less than during rhythmic exercise, TE was shortened, and TI was only slightly affected. Pa and HR, after a transitory reduction, increased over the resting levels. Similar responses were also obtained in deafferented rabbits with carotid sinus, aortic, and cervical vagus nerves cut. These two patterns of cardiorespiratory changes were initiated by activation of muscle receptors verified by interrupting the afferents from the contracting muscles. It is concluded that, in the anesthetized rabbit, two different muscular reflex mechanisms are involved in controlling the pattern of breathing and ventilation during muscular exercise. One mechanism, predominantly activated during dynamic exercise, decreases TE and increases f, the other mechanism, mainly activated during static exercise, increases the inspiratory drive, thus increasing the depth of breathing.

Animals↗
PubMed1983

[Aryloxy- and arylthioalkylamine hypolipidemic agents].

Aryloxy and arylthioalkylamines related respectively to clofibrate and 2-(3,5-di-t-butyl-4-hydroxyphenylthio)hexanoic acid, a derivative of an active probucol metabolite, were prepared and pharmacologically screened as hypolipidemic substances. Some of them showed interesting antilipemic activity but also, unfortunately, high acute toxicity.

Amines↗
PubMed1981

[Comparative study of cardiocirculatory response and respiratory reflex to the injection of bradykinin, inorganic phosphates and prostaglandins into the femoral artery].

In 15 anesthetized rabbits the reflex changes in arterial pressure, heart rate and respiratory rate in response to injections of bradykinin inorganic phosphate and prostaglandins into femoral artery have been studied. Intraarterial injection of bradykinin produced a reflex fall in arterial pressure, bradycardia and tachypnea. The latency of response ranged from 6 to 7 sec. The threshold dose was about 50 ng. This effect was accompanied by a consistent increase in the afferent discharge in the saphenus nerve. Isotonic mixtures of Na2HPO4 and NaH2PO4 at pH 7, PGE1, PGE2, and PGA, when injected into femoral artery even in high doses, failed to produce any significant cardiocirculatory or respiratory reflex responses. Infusion of PGE1 (1 ug/min) into femoral artery, although inactive by itself, enhanced the reflex effect of bradykinin.

Animals↗
PubMed1981

Cardiovascular and respiratory reflexes from muscles during dynamic and static exercise.

In anesthetized and deafferented rabbits, rhythmic and static contractions of the hindlimb muscles were elicited by stimulating the femoral nerve at 3 and 100 Hz with the intensity of 2.0-2.5 times threshold for the motor fibers. Rhythmic contractions caused a decrease in systemic blood pressure, heart rate, and vascular resistance of the resting hindlimb with hyperpnea. Tetanic contractions caused a rise in arterial pressure, in vascular resistance of the nonexercising hindlimb, and in pulmonary ventilation with small increases in heart rate. These responses were not obtained after sectioning the somatic nerves of the exercised limb or when the cut central end of the femoral nerve or the intact nerve in curarized animals was stimulated with the same intensity of 2.0-2.5 times the motor threshold. Both depressor and pressor responses were, therefore, reflexes initiated in the contracting limbs. Removal of the skin from the exercising limb did not change the typical patterns of response. The most likely source of the observed reflexes is that from receptors activated by metabolites released in the exercising muscles.

Animals↗