Serotonergic influences on food intake: effect of 5-hydroxytryptophan on parameters of feeding behaviour in deprived and free-feeding rats.
Three experiments were carried out to examine the effect of the serotonin precursor, 5-hydroxytryptophan, upon food intake and the micro-structure of eating in deprived rats, and on the pattern of meal taking in free-feeding animals. The study also investigated the capacity of a peripheral decarboxylase inhibitor (MK-486) to antagonise the effect of 5-HTP in order to identify a central or peripheral mode of action. In deprived rats 5-HTP brought about a dose related inhibition of food intake which was midly antagonised by MK-486. A detailed analysis of the behavioural changes occurring during eating showed that the inhibition of food intake by 5-HTP was reflected in a reduced number of eating bouts and a slower rate of eating. MK-486 did not antagonise the effect of 5-HTP on eating rate. In free-feeding rats whose food comsumption was continuously monitored for 24-hr periods, 5-HTP gave rise to reduction in meal size and a slowing of the intra-meal rate of eating. These findings are in keeping with the effects of other serotonergic manipulations on the patterns of feeding in rats.
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D002230:Carbidopa / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005247:Feeding Behavior / Q000187:drug effects*; D005508:Food Deprivation; D008297:Male; D051381:Rats; D012701:Serotonin / Q000502:physiology*; D013997:Time Factors
D012701:Serotonin; D006916:5-Hydroxytryptophan; D002230:Carbidopa