d-Amphetamine induces differential effects on locomotion, stereotypy and object recognition memory in female and male rats

V. BISAGNO; D. FERGUSON; V.N. LUINE

Quebec, Canada.

Congreso; 2002 CPDD Annual Meeting; 2002

CPDD

d-Amphetamine induces differential effects on locomotion, stereotypy and object recognition memory in female and male ratsV. Bisagno, D. Ferguson and V.N. LuineHunter College, City University of New York, New York, NYSince d-amphetamine (AMPH) produces greater scores for locomotion and stereotypy in female as compared to male rats, it is hypothesized that AMPH will also induce gender differences on cognition. We investigated object recognition memory during a withdrawal period following chronic AMPH or acute AMPH administration to female and male rats; and, measured locomotion, stereotypy and neurochemistry changes induced by an AMPH challenge dose after a 16-day withdrawal period. Sprague-Dawley male and female adult rats were treated chronically (N=8/10 per group), (10 i.p. inj., one every other day; males: 3mg/kg, females: 2.6 mg/kg), or acutely (N=8 per group) (one inj., same doses). Locomotion and stereotypy were also quantified. Object recognition memory was evaluated during the withdrawal period and after acute administration. Monoamines in brain areas were measured after a challenge dose on the 16th withdrawal day. Two-way ANOVA (sex X treatment) tested statistical significances. AMPH treated rats showed impairments in visual recognition memory during withdrawal, but no sex differences were found. However, after acute AMPH, treated males showed the lowest performance in the object recognition test. Females treated had higher scores of stereotypy and locomotion after an acute and chronic treatment but no gender differences were found after a challenge dose. In AMPH groups, striatal DA, 5-HTand 5-HIAA were increased (females also had higher 5-HT and less HVA), in substantia nigra 5-HIAA and 5-HIAA/5-HT were also increased. In nucleus accumbens, females had lower norepinephrine levels than males. Thus, both sexes showed memory impairments during the withdrawal period but after acute AMPH, object recognition performance was not impaired in females. Further, an amphetamine challenge dose after a withdrawal period did not amplify gender differences in locomotion/stereotypy or monoamine levels. This study provides novel information to better understand functional cognitive consequences of AMPH administration and suggests that females may have less/differential cognitive impairments to psychoactive drugs than males. MIDARP (R24 DA12136, NIDA)