TY - JOUR T1 - TRANS-SYNAPTIC INDUCTION OF ADRENAL TYROSINE HYDROXYLASE JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 249 LP - 254 VL - 169 IS - 2 AU - H. THOENEN AU - R. A. MUELLER AU - J. AXELROD Y1 - 1969/10/01 UR - http://jpet.aspetjournals.org/content/169/2/249.abstract N2 - Pretreatment of rats with 6-hydroxydopamine, reserpine and phenoxybenzamine, drugs which interfere with postganglionic sympathetic transmission by different mechanisms, induces an increase in the in vitro adrenal tyrosine hydroxylase activity. This increase in the rate-limiting enzyme in catecholamine synthesis can be prevented by interruption of the splanchnic nerves supplying the adrenal glands, whereas an elevation of the enzyme activity is still present in hypophysectomised animals. Adrenal denervation also partially prevents the depletion of catecholamines caused by reserpine and phenoxybenzamine. It is concluded that the elevation of tyrosine hydroxylase is mediated by a prolonged reflex increase in the splanchnic nerve activity as a consequence of drug-induced impairment of postganglionic sympathetic transmission. © 1969, by The Williams & Wilkins Co. ER -