(+)Amphetamine-stimulus generalization to an herbal ephedrine product.
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.
Glennon
R A
RA
Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298-0540, USA.
Young
R
R
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D003913:Dextroamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D004192:Discrimination, Psychological / Q000187:drug effects; D004809:Ephedrine / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D005795:Generalization, Stimulus / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000697:Central Nervous System Stimulants; D010936:Plant Extracts; D002110:Caffeine; D004809:Ephedrine; D003913:Dextroamphetamine