CHRONIC STRESS COUNTERACTS D-AMPHETAMINE IMPAIRMENT ON VISUAL MEMORY AND ALTERS SYNAPTIC PROTEIN EXPRESSION IN FEMALE RATS.

V. BISAGNO; C. GRILLO; G. PIROLI; P. GIRALDO; B. MCEWEN; V. N. LUINE

New Orleans, Louisiana, USA

Congreso; 2003 SFN Meeting; 2003

SFN

CHRONIC STRESS COUNTERACTS D-AMPHETAMINE IMPAIRMENT ON VISUAL MEMORY AND ALTERS SYNAPTIC PROTEIN EXPRESSION IN FEMALE RATS. V.Bisagno1*; C.A.Grillo2; G.G.Piroli2; P.Giraldo1; B.S.McEwen2; V.N.Luine1 1. Dept. Psychol, Hunter Col.CUNY, New York, NY, USA 2. Lab. of Neuroendocrinology, Rockefeller Univ., New York, NY, USA Since chronic d-amphetamine (AMPH), impairs memory and chronic stress enhances it in female rats(Bisagno et al., Endocrine, in press), we investigated the effect of combining daily chronic restraint stress (6h/day, 21 days) with chronic AMPH injections (10 i.p. inj., one every other day; 2.6 mg/kg) on locomotion and recognition memory in females. Also, synaptic proteins, synaptophysin and PSD-95, were measured by radioimmunocytochemistry (RIC) in brain areas in order to understand possible mechanisms for the behavioral changes. Locomotion, exploratory and anxiety parameters on the open field, and object recognition memory were measured; subjects were sacrificed 5 days after the last injection and serum corticosterone and synaptic proteins measured. AMPH impaired object recognition and increased locomotion, anxiety parameters and corticosterone levels. Stress did not alter these parameters, but stress blocked AMPH effects on object recognition and anxiety while it potentiated AMPH dependent locomotor effects. In the brain, AMPH groups showed decreased synatophysin expression in the hippocampus, and stressed subjects showed decreased PSD-95 expression in the caudate. Also, in the caudaute, the AMPH group showed an increase in synaptophysin expression, an effect that was reversed when stress was combined with the AMPH. Results suggest that chronic stress may counteract AMPH cognitive impairments by blocking anxiety-inducing effects of AMPH. Therefore, the AMPH + stress group was able to perform the object recognition task. The combination of AMPH + stress also blocked AMPH induced neuroplasticity in the caudate. This study provides novel information for understanding the functional cognitive consequences of AMPH use as well as the interactions between psychoactive drug abuse and stress.Support Contributed By: R24 DA12136, NIDA