Abstract
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.
Footnotes
- Received November 12, 1968.
- Accepted May 24, 1969.
- © 1969, by The Williams & Wilkins Company
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