THE INFLUENCE OF ANGIOTENSIN-II ON CATECHOLAMINE SYNTHESIS IN NEURONAL CULTURES FROM RAT-BRAIN

Incubation of primary neuronal cultures prepared from the hypothalamus and brainstem of neonatal rats with angiotensin II (Ang-II) resulted in a concentration-dependent effect on the incorporation of [3H]-tyrosine ([3H]-Tyr) into [3H]-catecholamines ([3H-CA). At concentrations of 1 nM-1μM, Ang-II (60 min. incubation) caused significant decreases (31-52%) in neuronal [3H]-CA content compared with controls. Conversely, higher concentrations of Ang-II (10-100 μM; 60 min.) caused significant increases (20-60%) in neuronal [3H]-CA content compared with controls. Both of these effects were blocked by co-incubation with the Ang-II receptor antagonist Sar1IIe8-Ang-II. These observations demonstrate that neuronal cells in primary culture have the ability to synthesize [3H]-CA from [3H]-Tyr, and that Ang-II has a receptor-mediated biphasic influence on newly synthesized [3H]-CA (norepinephrine and dopamine). © 1990.