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A C Cicogna

Publications and source records attributed to A C Cicogna.

48 records · Page 3Linked to original sources
PubMed1976

Evaluation of V max TP as an index of myocardial contractility during afterload and preload elevations.

In order to test if the maximal velocity of shortening (V max TP) reflects the level of inotropism and is affected by preload and afterload, the behavior of this index was compared in two groups of anesthetized, atropinized dogs when preload and afterload were raised with an angiotensin II infusion. In seven dogs (group I), the arterial pressure elevation was allowed to inhibit reflectively the sympathetic tone and depress contractility. In eleven dogs (group II), the adrenergic activity was abolished by previous administration of reserpine. In group I, there was a significant decrease in V max TP during the angiotensin infusion. In group II, there was no significant change in the value of this index when the drug was infused. In six animals of this group, a further increase of arterial pressure was induced, but the values of V max TP remained similar to control. These results suggest that this index reflects the inotropic state of the myocardium and does not suffer significantly from the influence of preload and afterload elevations within our experimental limits.

Angiotensin II↗
PubMed1975

Role of the autonomic nervous system in the inotropic variations induced by the infusion of angiotensin II.

Inotropic effects of angiotensin II were studied in 26 anesthetized dogs with different conditions of autonomic activity. The values of maximal velocity of contraction (Vmax TP) were compared before and 10 minutes after the arterial pressure was elevated by the infusion of the drug. In eight dogs, previously treated with atropine and reserpine, the administration of angiotensin had no effect on mean values of Vmax TP. Nine animals submitted to ganglionic blockade by hexamethonium presented an improvement of myocardial contractility when angiotensin was infused. In nine dogs studied with intact nervous system, infusion of the drug was accompanied by decrease of mean values of the index. It was concluded that the polypeptide exerts no important physiological effects upon myocardial contractility without the mediation of the autonomic nervous system. It was considered that the positive inotropic effect verified in dogs under ganglionic blockade was due to adrenergic hyperactivity induced by angiotensin. The depression of the contractile state observed in intact animals was supposed to be mediated by variations of autonomic nervous system activiity consequent to baroreceptor reflex.

Angiotensin II↗
PubMedDate not supplied

[Effects of bilateral common carotid arteries occlusion on vagal activity (author's transl)].

The effects of carotid occlusion on parasympathetic activity were studied in anesthetized dogs, submitted to beta adrenergic blockade. Modifications of the heart rate, before and after administration of atropine, were utilized for assessment of vagal changes. When vagal activity was intact there was elevation of the heart rate. After parasympathetic blockade carotid occlusion did not cause heart rate modifications. The data suggest that carotid occlusion produced vagal inhibition.

Animals↗