Studies on the central effects of adrenaline, ephedrine and N-methylbenzedrine by means of Circulating perfusion method of dog's head

Abstract

By means of our method (see this Breviaria, No. 63), the central effect upon blood pressure and respiration of, adrenaline and its homologues injected into the perfusion circuit 'of dog's head was investigated. Adrenaline reduced the systemic blood pressure and the respiratory, movement of the recipient dog. By a given dose of adrenaline, the degree of the fall was shown to be roughly proportional to the initial level. This central inhibitory effects of adrenaline upon both the blood pressure and the respiration were observed not only during the adjustment of the elevated perfusion pressure by adrenaline to preinjection level but also after denervation of vagus and/or carotid sinus nerves. N-Methylbenzedrine and ephedrine given intraarterially to the head, elevated the systemic blood pressure gradually, the effect of the latter being remarkably weaker than the former. The former stimulated the respiration, whereas the latter did not show any stimulation but caused inhibition. 'Both of them dilated slightly the blood vessels of the head.