Actions and interactions of neurotensin on preoptic anterior hypothalamic neurons in vitro

Considerable evidence has accumulated, suggesting that neurotensin (NT) interacts with neurotransmitter systems in the CNS. The purpose of this study was to investigate possible neurophysiological interactions between NT and putative neurotransmitters endogenous to the preoptic anterior hypothalamus (POAH). Using standard in vitro recording techniques, extracellular single unit activity was monitored in explant tissue cultures prepared from the POAH of newborn rats. Drugs were applied through the superfusion system or inotophoretically or pneumatically through micropipettes. Neurotensin produced a potent excitatory effect which enhanced lutamate induced excitations. In contrast, neurotensin reduced the effects of acetylcholine and had no effect on the actions of GABA and dopamine. These results suggest that interactions between NT and putative neurotransmitters in the POAH are highly specific.