BEHAVIORAL EFFECTS OF N, N-DIETHYLTRYPTAMINE: ABSENCE OF ANTAGONISM BY XYLAMIDINE TOSYLATE

¹ Department of Pharmacology, School of Medicine, State University of New York at Buffalo, Buffalo, New York; Department of Radiation Biology and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York

This investigation sought to differentiate the central and peripheral sites of action of N, N-diethyltryptamine(DET) as an aid to the interpretation of its effects on operant behavior. Rats were trained to press a bar for a food reinforcer which was delivered according to a fixed ratio schedule or a differential reinforcement of low rate schedule of reinforcement. DET, 5-hydroxytryptamine (5-HT) and 5-hydroxytryptophan (5-HTP) produced a depression of responding on the fixed ratio schedule. Cinanserin HCI antagonized the effects of all three agents. In contrast, xylamidine tosylate clearly antagonized 5-HT, was less active against 5-HTP and was without effect on DET. The response rate on the differential reinforcement of low rate schedule was also depressed by DET, 5-HT and 5-HTP. How- ever, the DET-induced pause in bar pressing was followed by a period in which the response rate was greater than control values. The latter effect was not produced by 5-HT and 5-HTP. Rate enhancement by DET was antagonized by cinanserin HCI but was not altered by xylamidine tosylate. These results indicate that DET can be differentiated from 5-HT and 5-HTP on a behavioral basis by the use of an appropriate schedule of reinforcement and on a pharmacologic basis by the use of selective antagonists. These results support the hypothesis that DET acts on 5-HT receptors in the central nervous system to produce its behavioral effects in the rat.