(+)Amphetamine-stimulus generalization to an herbal ephedrine product.


Glennon RA, Young R




Pharmacol Biochem Behav


We have previously demonstrated that a (+)amphetamine stimulus generalizes both to (-)ephedrine and caffeine. Using rats trained to discriminate intraperitoneal (IP) administration of 1.0 mg/kg of (+)amphetamine (ED(50) = 0.4 mg/kg) from saline vehicle in a standard two-lever drug discrimination procedure, the present investigation shows that the (+)amphetamine stimulus generalizes to (+)amphetamine (ED(50) = 1.0 mg/kg) when administered via the intragastric (IG) route, and that (+)amphetamine appears about 2. 5-fold less potent when administered via the IG route compared to the IP route. Likewise, (-)ephedrine (ED(50) = 10.8 mg/kg) and caffeine (ED(50) = 32.9 mg/kg) are also 2.5-fold less potent when administered via the IG route compared to their potency when administered via the IP route. The (+)amphetamine stimulus also generalizes to an IG- administered herbal preparation (i.e., Herbal XTC; the herbal preparation possesses an approximate potency roughly comparable to what might have been expected on the basis of its reported ephedrine and/or caffeine content. These results demonstrate, for the first time, that an ephedrine-containing herbal preparation can produce a (+)amphetamine-like effect in animals.