METHAMPHETAMINE-INDUCED DOPAMINE AND SEROTONIN REDUCTIONS IN NEOSTRIATUM ARE NOT GENDER-SPECIFIC IN RATS WITH COMPARABLE HYPERTHERMIC RESPONSES

Methamphetamine (MA)-induced monoamine depletions in male and female S prague-Dawley CD rats were studied under conditions in which the magni tude of MA-induced hyperthermia was comparable between the sexes. MA ( 5 or 10 mg/kg) or saline (3 ml/kg) was administered SC four times at 2 -h intervals. Animals were sacrificed 3 days posttreatment for the det ermination of dopamine (DA), serotonin (5-HT), and metabolites. MA ind uced significant monoamine reductions but the magnitude of these reduc tions was not significantly different between males and females. In th e MA 5 mg/kg groups, neostriatal DA content was reduced by 51.2% and 4 4.8%, whereas 5-HT content was reduced by 30.6% and 23.9% of controls for males and females, respectively. In the MA 10 mg/kg groups, neostr iatal DA content was reduced by 72.9% and 65.8%, whereas striatal 5-HT content was reduced by 77.4% and 73.6% of controls for males and fema les, respectively. No significant differences in thermal responses to MA were observed between genders. Unlike reports in mice, gender does not play a role in MA-induced monoamine reductions in rat neostriatum when MA-induced hyperthermia is comparable across sexes. The data also showed a threshold effect in which dopamine depletions were not corre lated with hyperthermia at core body temperatures above approximately 41 degrees C. (C) 1998 Elsevier Science Inc.