An endogenous opiate mechanism seems to be involved in stress-induced anhedonia.

ALEJANDRA ZURITA,; MURUA, S.; MOLINA VICTOR ALEJANDRO

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1996 vol. 299 p. 1 - 1

his study assessed the effect of an uncontrollable stressor on the preference for a palatable solution (sucrose 1%), and on the preference for a context associated with a single administration of D-amphetamine (3 mg/kg i.p.) by means of the conditioning place preference test. We also evaluated the effect of prior naloxone (2 mg/kg, i.p.) administration on the influence of this stressful stimulus in both tests. Animals previously submitted to a 120-min - but not 60-min - restraint period showed a selective reduction in the preference for sucrose intake as compared to unstressed animals. Similarly, an identical restraint exposure elicited a diminished preference for the place previously paired with amphetamine. Both stress-induced effects were blocked by prior naloxone administration. These data demonstrate that a highly aversive experience decreased the reinforcing efficacy of sucrose and amphetamine, suggesting that uncontrollable stress may lead to an impaired capacity to experience