Tonic serotonergic control of ingestive behaviours in the pigeon (Columba livia): the role of the arcopallium.

This study examined the acute changes in feeding and drinking behaviours of free-feeding and free-drinking pigeons, in response to local injections of metergoline (MET, 5-HT(1/2) receptor antagonist; 7 and 20 nmol), GR46611 (GR, 5-HT(1B/1D) agonist; 2 and 6 nmol) or vehicle, into two components of the arcopallium: the nucleus taeniae of the amygdala (TnA) and the arcopallium intermedium (AI). In the TnA, the highest MET dose elicited a short-lived hyperphagy, without affecting drinking or non-ingestive behaviours during the first hour after injection. In contrast, all MET doses promptly increased drinking when injected in the AI, without affecting feeding; this effect was still evident 3 and 24 h after the treatment.

Ingestive effects of NMDA and AMPA-kainate receptor antagonists microinjections into the lateral hypothalamus of the pigeon (Columba livia).

This study examined the ingestive and behavioral effects of NMDA- and AMPA/kainate glutamatergic receptor blockade in the lateral hypothalamic area (LHy) of free-feeding pigeons (Columba livia). Injections of MK-801 (NMDA receptor antagonist; 6 nmol) or CNQX (AMPA/kainate receptor antagonist; 25.8 nmol) into the LHy of free-feeding pigeons induced significant increases in food intake and in feeding duration, as well as reductions in the latency to start feeding.