THE EFFECT OF SEROTONIN INJECTED INTRAARTERIALLY ON THE CUTANEOUS NERVE ADDITIONALLY CONTRASTED WITH NOR-EPIRENAMINE.

Abstract

Serotonin has been reported to be a pain-producing substance and confiremed to cause the cutaneous nervous discharge by the arteri al injection. On the other hand, serotonin has an obvious effect on blood vessels. The relationships among the above three facts derived from serotonin action have not been yet clarified. In the present paper, the auther intended to investigate the nature of the discharge in rabbit's saphenous nerve from the aspect of blood circulation change by the injection of serotonin into the femoral artery and contrasted with that of nor­ epirenamine. Serotonin evoked the bimodal discharge enhancement in dose, which have an effect on the blood pressure. On the injection of a mixture of serotonin and nor­ epirenamine, both were compensated by each other and the blood pressure alter­ nation was not observed, but the first phase of the enhancement remained. This phase appeared soon' after the injection and was intensified by venous occlusion. Neither blood pressure change nor the second enhancement was observed with the venous occlusion, but in larger dose, the second one was evoked coinci­ dently with the blood pressure change after the release of occlusion. Then, the second enhancement was considered to be closely related with the blood pressure change. The discussion was particularly directed to the existence of baroreceptor of the peripheral blood vessels.