Abstract
The studies of Schmitterlow (1) have indicated that the noradrenaline-like vasopressor substances were to be present in extracts from blood vessels. Burn and Rand (2, 3) confirmed that in the walls of arteries there was an appreciable amount of noradrenaline and that it was depleted by reserpine pretreatment as catecholamines in other organs. Maxwell et al. (4), Schmidt and Fleming (5) and Trendelenburg et al. (6) showed that the response to sympathomimetic amines was altered after the subjects had been treated with reserpine. It is suggested that the mode of action of these amines on vascular smooth muscle may be modified by the changes of the amount of noradrenaline stores in the tissue.
In the present experiments the sensitivity to noradrenaline and tyramine was investigated by using smooth muscle strips prepared from various regions of the vascular system. The difference of the sensitivity was discussed with reference to the concentrations of noradrenaline present normally, depleted with reserpine, or absent inherently.
