Cardiovascular effects of novel amphetamine analogs in anesthetized rats

In albino, adult Sprague Dawley rats, anesthetized with urethane intraperitoneally, the effects of the exo- and endo-isomers of 2-amino-5,8-dimethoxybenzonorbornene were studied on arterial blood pressure and heart rate. Both compounds produced an immediate rise in systemic arterial pressure followed by an immediate maximal depressor response. The depressor effect was sustained beyond 30 minute duration, but declined in intensity with time to nearly preinjection levels. Both compounds decreased heart rate in varying degrees. Evidence of marked bradycardia and onset of toxicity was observed at doses of 12.8 mg/kg (exo) and 19.2 mg/kg (endo). The biphasic response seen after intravenous injection of the compounds suggests an initial vasoconstrictory followed by a vasodilatory effect.