alpha-Ethyltryptamine (alpha-ET) as a discriminative stimulus in rats.
Richard A Glennon, Tatiana Bondareva, Richard Young
Pharmacology, biochemistry, and behavior October 1, 2006 DOI: 10.1016/j.pbb.2006.09.014 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Drug discrimination study Peer reviewed |
|---|---|
| Population | Male Sprague-Dawley rats |
| Intervention | alpha-Ethyltryptamine (alpha-ET) |
| Dose | 2.5 mg/kg training dose; ED50 values: 1.3 mg/kg (alpha-ET), 1.6 mg/kg (S(-)alpha-ET), 1.3 mg/kg (R(+)alpha-ET), 0.4 mg/kg (DOM), 0.7 mg/kg (PMMA) |
| Duration | 30-min pretreatment time; duration of effect at least 4 h |
| Measures | drug-appropriate responding |
| Key points | alpha-ET produces a complex stimulus that fully generalizes to DOM and PMMA but only partially to amphetamine. |
Abstract
alpha-Ethyltryptamine (etryptamine, alpha-ET) is a drug of abuse that first appeared on the clandestine market in the mid-1980s. Its pharmacological actions are poorly understood. In this investigation, it is reported for the first time that alpha-ET serves as a training drug in drug discrimination studies. Male Sprague-Dawley rats were trained to discriminate (30-min pretreatment time) 2.5 mg/kg of alpha-ET (ED(50)=1.3 mg/kg) from saline vehicle using a standard two-lever operant paradigm and a VI-15s schedule of reinforcement for appetitive reward. Once established, the alpha-ET stimulus was shown to have an onset to action of 30 min and a duration of effect of at least 4 h. In tests of stimulus generalization (substitution), the alpha-ET stimulus generalized to S(-)alpha-ET (ED(50)=1.6 mg/kg) and R(+)alpha-ET (ED(50)=1.3 mg/kg). Tests of stimulus generalization were also conducted with prototypical phenylisopropylamines: (+)amphetamine, 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM), and N-methyl-1-(4-methoxyphenyl)-2-aminopropane (PMMA). The alpha-ET stimulus generalized to DOM (ED(50)=0.4 mg/kg) and PMMA (ED(50)=0.7 mg/kg), but only partially generalized (ca. 40% maximal drug-appropriate responding) to (+)amphetamine. The results suggest that alpha-ET produces a complex stimulus.