Activation of central neurotensin receptors reinstates cocaine seeking in the rat: modulation by a D1/D5, but not D2/D3, receptor antagonist.

Rationale: Neurotensin (NT) has been implicated in some of the behavioral effects of psychostimulants. Thus, there is reason to think that NT may play a role in the reinstatement of cocaine seeking, and that it may do so via an interaction with dopamine (DA).

Objectives: To assess (1) whether NT and an NT analog, D-TYR[11]NT, induce reinstatement of cocaine seeking; (2) whether the effects of NT receptor activation on reinstatement can be modulated by D1/D5 or D2/D3 antagonists; (3) the specificity of the effects of NT receptor activation on the reinstatement of cocaine seeking.

Modulation of the pair housing induced feeding suppression.

The present experiments explored how manipulating the period of individual housing, partner novelty, or short periods of conspecific interaction affected the feeding suppression evident when young adult male rats were moved from individual to pair housing. In the first experiment, after a period of pair housing, rats were individually housed for 0, 3, 10, or 14 days before being rehoused with either the same or a novel partner. There was an increase in the feeding suppression as the duration of individual housing grew, and at 3 days, the novel partner produced a stronger suppression than did the familiar partner.