Feeding and drinking response of young chicks to injections of serotonin into the lateral ventricle of the brain

The effects of serotonin [5-hydroxytryptamine (5-HT)] on food intake and water consumption were investigated in young broiler chicks. Artificial cerebrospinal fluid containing either 0, 33, 67, or 100 microgram of 5-HT/10 microliter was injected into the lateral ventricle of either 24-hr fasted or fully fed chicks maintained in a thermoneutral environment with continuous lighting. Neither cannulation per se nor injection of 10 microliter of artificial cerebrospinal fluid had an effect on food intake or water consumption. Furthermore, food intake was not affected by 5-HT in fasted chicks. In fully fed chicks, however, food intake was significantly decreased by 67 and 100 microgram of 5-HT. Water consumption was affected by 5-HT injection in fully fed chicks. Results with fasted chicks remain equivocal. Data suggest that 5-HT may be involved in the neurohumoral control of food intake.