[Interaction of catecholamine and opiate structures of the brain at the neuronal level]

Nalorphine administered systematically inhibited the responses of the rat lateral hypothalamic neurons to phenamine. The blocking effect of nalorphine was not obvious in microiontophoretic application. Nalorphine being injected into the substantia nigra (which sends nerve fibers to the lateral hypothalamus) and phenamine being applied to the single lateral hypothalamic neurons, the phenamine responses were suppressed in 34% of cases. The results suggest that substantia nigra's opiate structures are able to modulate presynaptically the functions of the lateral hypothalamic neuronal dopamine receptors.