Ingestive behaviors and metabolic fuels after central injections of 5-HT 1A and 5-HT 1D/1B receptors agonists in the pigeon

Abstract

The effects of intracerebroventricular injections of 8-OH-DPAT (a 5-HT 1A agonist; 3, 15 or 30 nmol) or GR46611 (a 5-HT 1B/1D agonist; 3, 15 or 30 nmol) on feeding, drinking, preening and sleep-like behaviors were investigated in free-feeding (FF) pigeons. The effects of these 5-HT agonists on blood glucose and free fatty acids levels were also examined. Injections of 8-OH-DPAT evoked intense lipolytic and dipsogenic effects, but failed to affect feeding, non-ingestive behaviors and glycemic levels. On the other hand, GR46611 evoked significant increases in food intake (at the higher dose), as well as lipolytic and hyperglycemic effects, but left drinking and other non-ingestive behaviors unchanged. These effects are opposed to those found in rodents, and may be associated with the diverse, species-specific nature and distribution of these receptors, underscoring the need to examine the functional aspects of the 5-HT 1 receptor family in a more extensive range of non-rodent species.