Response of normal, denervated, and reserpine-treated arteries to sympathomimetic amines and nicotine in dogs.

The sensitivity of normal, denervated carotid arterial segments, and of carotid arteries of dogs previously treated with reserpine, to sympathomimetic amines and nicotine has been compared using isolated perfused segments of these vessels. Arteries from animals and arterial segments treated with reserpine, denervated by peri-arterial stripping or by re-anastomosing of segments removed and reversed, both showed an increased sensitivity to noradrenaline which correlated well with a decrease in tissue noradrenaline content. Tyramine did not produce vasoconstriction in denervated vessels, but some constriction was observed when the vessels had been pretreated with noradrenaline or with dopamine or dopa. The effect of nicotine upon dog carotid arterial segments was recorded 130 times. The most frequent response was vasodilatation. This involved both the arterial wall per se and the vasa vasorum. The vasodilatation in response to nicotine was seen in arteries from normal and reserpine-treated animals and in denervated vessels.