Repeated neurotensin administration in the ventral tegmental area: effects on baseline and D-amphetamine-induced locomotor activity.

Microinjections of neurotensin (NT) into the ventral tegmental area (VTA) of the rat increases locomotor activity. This effect on locomotion is potentiated by daily infusions of NT; in contrast a different injection schedule, i.e. every 48 h, had no such effect. In addition, daily NT injections in the VTA do not alter the locomotor response to a relatively low dose (0.5 mg/kg) of D-amphetamine. These results provide further evidence that NT can modulate the mesolimbic dopamine pathway.