TY - JOUR T1 - THE EFFECT OF <em>d</em>-AND <em>l</em>-NOREPINEPHRINE ON RAT CARDIAC PHOSPHORYLASE ACTIVATION JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 97 LP - 101 VL - 165 IS - 1 AU - JOHN H. McNEILL AU - THEODORE M. BRODY Y1 - 1969/01/01 UR - http://jpet.aspetjournals.org/content/165/1/97.abstract N2 - Intact, anesthetized rats were infused with various doses of d- and l-norepinephrine, and the activity of the enzyme glycogen phosphorylase was determined. The d-isomer of norepinephrine activated the enzyme to the same extent as did the l-isomer but was as potent. Simultaneous infusions of both d- and l-norepinephrine resulted in a shift to the left of the l-norepinephrine dose-response curve. Pretreatment with tripelennamine did not further shift the dose-response curves obtained when d- and l-norepinephrine were infused together or when d-norepinephrine was infused alone. Reserpine pretreatment did not affect the response to d-norepinephrine, but the response was blocked by propranolol. It was concluded that d-norepinephrine has a direct action on the cardiac beta adrenergic metabolic receptor and that d-norepinephrine utilizes the same active uptake mechanism as l-norepinephrine in the rat heart. © 1969, by The Williams &amp; Wilkins Company ER -