THE EFFECT OF ACUTE MDMA ADMINISTRATION ON BODY-TEMPERATURE, SERUM CORTICOSTERONE AND NEUROTRANSMITTER CONCENTRATIONS IN MALE AND FEMALE RATS

The aim of this study was to examine the effect of acute administratio n of (+/-)3,4-methylenedioxymethamphetamine (MDMA) (20 mg/kg, i.p.) on colonic temperature, serum corticosterone and brain biogenic amine co ncentrations in group-housed male and female rats and to determine if there are any gender differences in susceptibility to MDMA-induced cha nges. Prior to treatment, basal colonic temperatures were higher in fe male than in male rats (p<0.05). Temperatures were significantly incre ased 30 min following MDMA (20 mg/kg, i.p.) in male rats (p<0.05), and 120 min following MDMA in female rats (p<0.05), and were still elevat ed 240 min following MDMA administration in both sexes. Basal corticos terone concentrations were also higher in female than in male rats (p< 0.05), prior to treatment. Serum corticosterone concentrations were si gnificantly elevated in both male and female rates 15 min after MDMA a dministration (p<0.001), and remained elevated for up to 4 h following MDMA (p<0.001 and p<0.05 respectively). 5-Hydroxytryptamine (5-HT) an d 5-hydroxy-indole-3-acetic acid (5-HIAA) concentrations were signific antly depleted in the frontal cortex, hypothalamus and striatum of bot h male and female rats. However, pineal 5-HT was resistant to depletio n by MDMA in both male and female rats. The 5-HIAA concentration was s ignificantly reduced in the pineal gland of female rats, probably due to decreased catabolism of pineal 5-HT. There was a profound decrease in the ratio 5-HT/5-HIAA in the frontal cortex but no changes occurred in these ratios in the striatum, hypothalamus or pineal gland in eith er male or female rats. Dopamine (DA) concentrations were increased an d 3,4-dihydroxyphenyl-acetic acid (DOPAC) levels decreased in the stri atum in both male and female rats 4 h after MDMA administration. The n oradrenaline (NA) content of the hypothalamus was increased in male ra ts 30, 60 and 120 min post MDMA (p<0.05) but no changes were noted in the hypothalamus of female rats. This study indicates that there are s light gender differences in susceptibility to MDMA-induced changes in rats.