THE RELATION BETWEEN NOREPINEPHRINE CONTENT AND RESPONSE TO SYMPATHETIC NERVE STIMULATION OF VARIOUS ORGANS OF CATS PRETREATED WITH RESERPINE

¹ Department of Pharmacology, Harvard Medical School, Boston, Massachusetts

After pretreatment of cats with various doses of reserpine, the catecholamine content of the right atrium, of the nictitating membrane and of the left adrenal gland of spinal cats was compared with the response of these organs to preganglionic sympathetic stimulation applied at various rates. The sensitivity of the right atrium to the catecholamine-depleting action of reserpine was highest, that of the adrenal medulla lowest. Similarly, the response of the cardiac pacemaker to sympathetic nerve stimulation was significantly depressed by doses of reserpine which did not yet affect the response of the nictitating membrane to sympathetic stimulation; the response of the adrenal medulla to splanchnic stimulation was least sensitive to reserpine. In all three organs, no significant decline in the response to sympathetic stimulation was observed unless the catecholamine content had fallen below 50% of normal. On the other hand, measurable responses were still observed when the catecholamine content was well below 10% of normal.