Effects of peripheral neurotensin on behavior of the rat.

Neurotensin (NT), a tridecapeptide found in brain and gut neurons, inhibits feeding and grooming, increases drinking, and enhances ethanol-induced sedation in rats after central injection. We tested the behavioral effects of IP injection of NT (0.1-100 micrograms/kg) in water-deprived rats given access to 5 or 10% ethanol for 30 min, followed by 30-min access to water. Behaviors during alcohol access were quantified with an instantaneous time-sampling observational technique. Food intake and observed feeding and grooming behaviors were significantly inhibited by large doses of NT (10-100 micrograms/kg) and water intake and resting behavior were increased. When the "limited access procedure" was used to induce ethanol selection in nondeprived rats, NT did not affect ethanol or water intake. Peripheral NT affects intake of food and water and observed feeding, grooming, and resting after peripheral injection in deprived rats, but does not affect ethanol consumption. These actions suggest physiological roles for endogenous neurotensin and its receptors in regulation of specific behaviors.