Dissociation in the modulatory effects of environmental novelty on the locomotor, analgesic, and eating response to acute and repeated morphine in the rat.

Rationale: We have previously shown that environmental novelty can potentiate the activating effects of morphine and the development of sensitization to this effect. OBJECTIVES. Our main goal was to determine whether environmental novelty can also modulate the prophagic (time spent eating and food intake; experiment 1) and/or the analgesic (tail-flick test; experiments 2 and 3) effect of morphine, as well as the development of tolerance or sensitization to these effects.

Dissociation in the effects of the D2/D3 dopaminergic agonist quinpirole on drinking and on vasopressin levels in the rat.

In the present study, we investigated the role of vasopressin in the development of quinpirole-induced hyperdipsia in the rat. We report that: (1), an acute intraperitoneal (i.p.