Evidence for serotonergic modulation of sucrose sham-feeding in the gastric-fistulated rat.

Both the real and sham intakes of a 5% sucrose solution were reduced by d-fenfluramine, quipazine (a 5-HT receptor agonist), and fluoxetine (a selective 5-HT reuptake inhibitor). These data demonstrate a serotonergic inhibitory component in the control of sham-feeding. In support of this, 8-OH-DPAT (a selective 5-HT1A agonist), which inhibits serotonergic activity at small doses via an autoreceptor mechanism, enhanced sucrose sham-feeding and reversed the suppressant effect of d-fenfluramine. Together, the results indicate a serotonergic influence on ingestional responses which is probably closely related to the oropharyngeal control of consumption.