Abstract
It has been reported that xylamidine, a specific peripheral 5-HT2 antagonist, attenuates, but does not completely block, 5-HT-induced anorexia, and that this effect may be mediated by both 5-HT2 and non-5-HT2 receptor subtypes. To determine whether this incomplete antagonism was a consequence of xylamidine’s being given at suboptimal doses, the dose-response characteristics of xylamidine on the anorexia induced by a dose of 5 mg/kg of 5-HT was investigated; the asymptote of the dose-response curve began at about 0.75 mg/kg. A second reason for the incomplete attenuation of 5-HT-induced anorexia would be that xylamidine has confounding nonspecific behavioral and/or ingestive effects. Xylamidine was found not to alter gross drinking behavior, and in a 2-bottle test, it did not, unlike lithium chloride, produce a conditioned taste aversion. The effects of xylamidine on drinking behavior and conditioning cannot account for the previously reported failure of xylamidine to completely block peripheral 5-HT-induced anorexia, and the possibility of non-5-HT2 receptors’ being partially responsible for the mediation of this anorectic effect remains open.
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This research was supported by a Science and Engineering Research Council grant to S. Edwards and was carried out at the University of Nottingham.
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Edwards, S., Stevens, R. Effects of the peripheral 5-HT2 antagonist xylamidine on consummatory behaviors. Psychobiology 19, 243–246 (1991). https://doi.org/10.3758/BF03332074
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DOI: https://doi.org/10.3758/BF03332074