Analysis of compensatory mechanisms of arterial hypertension in norepinephrine infusion

: The NA infusion induced a raise in the AP, inhibition of sympathetic vasomotor activity and a drop in the heart rate in alert male cats. The hypertensive effect of the NA was weakening during first 90 min of the infusion, a complete inhibition of sympathetic activity persisted during the whole period of infusion as well as a decrease in the heart rate, in anesthetized cats. After deafferentation, the markedness of the arterial hypertension weakening decreased and the effect of the infusion on sympathetic activity and heart rate was abolished. Administration of pentamine during the infusion did not affect the AP in anesthetized cats, increased it in alert animals and decreased the AP in deafferented cats. The organism seems to have no humoral mechanisms of compensation of arterial hypertension induced with the 3-hr infusion of noradrenaline.