Atrial natriuretic peptide and angiotensin II interaction on noradrenaline uptake in the central nervous system

The effects of different concentrations of atrial natriuretic peptide and angiotensin II on [3H]-noradrenaline uptake in hypothalamus and medulla oblongata slices incubated in vitro were determined. Atrial natriuretic peptide, in a dose of 100 mM, increased [3H]-noradrenaline uptake in both regions, while 1 microM of angiotensin II had the opposite effect. The ineffective concentration of 1 nM atrial natriuretic peptide reversed the action of 1 microM of angiotensin II on [3H]-noradrenaline uptake, whereas ineffective concentrations of angiotensin II failed to modify atrial natriuretic peptide effects. These results are compatible with the existence of an atrial natriuretic peptide-angiotensin II interaction in the central nervous system and with the hypothesis that some of the hypotensive effects of atrial natriuretic peptide could occur through modulation of an angiotensin-noradrenergic mechanism in the central nervous system.