Aims: 

Ecstasy (MDMA) has powerful acute physiological effects in humans: hyperthermia, hyponatraemia, hypertension and increase in heart rate. Little is known about what exactly MDMA does to those physiological responses. We, therefore, investigated acute effects of MDMA on arterial blood pressure, heart rate, respiratory rate and body temperature in anaesthetized rats.

Methods: 

Invasive arterial blood pressure, heart rate, respiratory rate and body temperature were recorded in pentobarbital-anaesthetized male rats for 2 hours after single i.v. injected with vehicle (n = 7), 5 mg/kg MDMA (n = 8) and 10 mg/kg MDMA (n = 8).

Results: 

In comparison between groups, there was no significant difference in diastolic blood pressure and respiratory rate at any stage of measurement. Intragroup comparison (5 mg/kg MDMA and 10 mg/kg MDMA groups) showed that MDMA markedly decreased mean arterial blood pressure (MABP), systolic blood pressure and heart rate (p < 0.05, compared with baseline). MDMA induced significant and non-dose-dependent decreases in MABP, systolic blood pressure and heart rate over 2 hours of investigation (p < 0.05, compared with control group). There were significant decreases in body temperature over baseline in both MDMA groups (p < 0.05). Interestingly, significant increases in body temperature were observed 20 minutes after administration of 5 mg/kg MDMA (34.98 ± 0.19 °C) and 10 mg/kg MDMA (34.88 ± 0.31 °C) compared with control group (34.33 ± 0.12 °C) (P < 0.05, two way repeated measures ANOVA).

Conclusion: 

This study provided the first evidence of transient hyperthermia response and prolonged cardiovascular effects (decreases in MABP, systolic blood pressure and heart rate) following acute MDMA in anaesthetised rats.