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-1 microM, 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 microM; 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 Sar1Ile8-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).