EFFECT OF NALOXONE, HALOPERIDOL AND PROPRANOLOL ON CYCLIC 3',5'-ADENOSINE-MONOPHOSPHATE CONTENT OF RAT AMYGDALA

Naloxone (0.4 mg/kg, i.p.) causes an increase of cyclic adenosine monophosphate levels in the amygdala, but not in the hippocampus, caudate, or hypothalamus, of rats. The effect is antagonized by haloperidol (0.5 mg/kg, i.p.) and by propranolol (0.5 mg/kg, i.p.). This is consistent with the hypothesis of a tonic inhibitory influence of endogenous opiates on central dopaminergic and β-noradrenergic systems. Haloperidol had an effect of its own on amygdala cyclic adenosine monophosphate levels which was blocked by propranolol. This suggests the possibility of an antagonistic interaction between dopaminergic and β-noradrenergic innervation on this structure. © 1979.