Intranigral microinjection of neurotensin suppresses feeding in food deprived rats.

This study was conducted to determine whether the substantia nigra is involved in the anorectic effect of centrally administered neurotensin. Microinjection of neurotensin (2.5 - 10.0 micrograms) into the substantia nigra produced a significant suppression of feeding in 18 hour food deprived rats. To determine if the anorectic effect resulted from a general impairment of sensory-motor functioning, eight behaviors were measured in a separate study. Significant effects were found in only two of the eight behavioral categories (sniffing and eating), and only at the highest neurotensin dose (10.0 micrograms). These results suggest that the substantia nigra may be involved in the anorectic effect of neurotensin.