Abstract: | Adrenalin solution (1:1000) administered at the carotid sinus, through excitation of the depressoric C-fibre system of the carotid nerve, induces a strong, lasting reflectoric decrease of arterial pressure with slowing heart rate, associated with an almost complete inhibition of the efferent sympathetic activity of the renal nerve. The efferent sympathetic activity, arterial blood pressure and heart rate, both at the onset and at the height of adrenalin action, show corresponding activity changes: the relative inhibition of the sympathetic nerve is strongest correlated with the depressoric blood-pressure effect, while the decrease of heart rate, related to the initial activity, is least pronounced. |