REPLETION OF CARDIAC CATECHOLAMINES IN THE RAT: IMPORTANCE OF THE ADRENAL MEDULLA AND SYNTHESIS FROM PRECURSORS

¹ Department of Pharmacology, College of Medical Sciences, University of Minnesota, Minneapolis, Minnesota

After a single olose of reserpine, maximum depletion of cardiac catecholamines in the rat occurred at 4 hours, and complete repletion was not seen until after about 10 days. Administration of norepinephrine at various intervals to reserpinized rats showed that only after 72 hours was there significant uptake of the injected amine. A positive correlation appears to exist between extent of depletion of catecholamines and degree of impairment of uptake of exogenous norepinephrine. Adrenal demedullation or pretreatment with chlorpromazine or cocaine retarded the repletion of cardiac catecholanuines in reserpine depleted animals. Administration of l-dopa or dopamine significantly increased the rate of repletion of cardiac catecholamines in adrenal demedullated rats which had been treated with reserpine.