Neurotensin attenuates dopamine D2 agonist quinpirole-induced inhibition of midbrain dopamine neurons.

The effects of intracerebroventricular (i.c.v.) administration of NT on the activity of midbrain DA neurons were studied in rats using single unit recording techniques. NT (i.c.v., 50 micrograms) was found to have no significant effect on the spontaneous activity of DA cells. On the other hand, NT treatment significantly attenuated the inhibitory effect of quinpirole (i.v.), a specific D2 agonist, on a subpopulation of DA cells. This result is consistent with previous behavioral and biochemical studies suggesting that NT may produce some of its effects through modulation of central DA systems.