Effect of angiotensin II and its analogs on uptake and release of 14C-5-hydroxytryptamine by rat brain

Uptake of 14C-labelled 5-hydroxytryptamine (14C-5-HT) has been investigated by perfusion of the rat brain ventricular system. When angiotensin II was present during perfusion, a dose-dependent inhibition of 14C-5-HT uptake in rat brain was observed. A similar effect was obtained with angiotensin II analogs (8-alanine angiotensin II or 1-dimethylglycine, 8-isoleucine angiotensin II). The inhibitory effect of angiotensin II can be almost completely blocked with 1-dimethylglycine, 8-isoleucine angiotensin II. In washout experiments, the radioactivity remaining in the brain was greater in the presence of angiotensin II.