[Interaction of the enkephalin- and dopamine-containing systems of the caudate nucleus head in realizing a conditioned food reflex in dogs].

Bilateral microinjections of 15 and 45 mg of Ley-enkephalin synthetic analogue D-Ala2-D-Leu enkephalin-Arg6 into the head of caudate nuclei in dogs enhanced parameters of Pavlovian alimentary conditioned reflexes and improved the differential inhibition. Microinjection of 60 mg dopamine exerted opposite effects. The opiate antagonist naloxone (0.8 mg) prevented the effects of both enkephalin and dopamine whereas a microinjection of dopamine-receptors blocking agent haloperidol (10 mg) prevented only the dopamine effects. The data suggest enkephalin-dopamine functional interaction to occur in neostriatal area in alimentary conditioning behaviour.