Male C-57 WT mice (22–35 g) were injected s.c. with the putative a1B-adrenoceptor antagonist cyclazosin (1.0mg/kg). Cyclazosin was administered 30 min prior to the injection of vehicle (1 ml/kg) or MDMA (20mg/kg). The putative a1B-adrenoceptor antagonist cyclazosin (1mg/kg) in vehicle experiments did not significantly alter the body temperature when compared to vehicle group. The pretreatment of mice with cyclazosin significantly altered the effect of MDMA on core body temperature

Sections of the abdominal aorta, obtained from adult female New Zealand rabbits, were treated with agonists and antagonists of adrenergic receptors. Administration of cyclazosin at a dose of 0.002 μM caused a decrease in the muscle tonus of -0.49 ± 0.10 mN. After blockade of the α1B-adrenergic receptor by 0.02 mkM cyclazosin, the administration of 0.05 μM phenylephrine resulted in an increase of the aortic muscle tonus of 1.49 ± 0.14 mN.