The influence of 1,3-dimethyl-5-adamantanamine (D-145) on catecholaminergic neurons of the rat brain, Histofluorescence studies.

The effect of a compound stimulating central dopaminergic structures, 1,3-dimethyl-5-adamantanamine (D-145), on the intensity of fluorescence in catecholaminergic nerve endings in some regions of the rat brain, mainly in the striatum and hypothalamus, was investigated with the modificated histofluorescence technique of Falck and Hillarp. D-145 (20 mg/kg), 2-3 hr after the administration depressed the intensity of catecholamine (CA) fluorescence in caudate-putamen (CP) and hypothalamic paraventricular nucleus (PVH). A blockade of dopamine (DA) receptors with spiperone (SPIRO, 2 mg/kg, 5 min before D-145) abolished the D-145 effect in PVH, thus indicating an indirect effect of D-145 on PVH, via a dopaminergic system. D-145 potentiated the depression of CA fluorescence produced by alpha-methyl-tyrosine methyl ester (H 44/68), 250 mg/kg ip. High doses of the CA synthesis inhibitor (2 X 400 mg/kg ip) prevented the developing of stimulation produced by D-145. These data indicate that the action of D-145 on DA receptors is indirect, via endogenous DA.