Distribution of neuropeptide Y in the brain of the male native Thai chicken.

INTRODUCTION . Neuropeptide Y (NPY), a 36 amino acid neurotransmitter/neuromodulator, is involved in food intake and parental cares in birds. NPY is associated with the regulation of the reproductive system in the female native Thai chickens. However, the role of NPY in the male native Thai chicken has not been studied. Therefore, the objective of this study was to investigate the distributions of NPY immunoreactive (-ir) neurons and fibers in the brain of the male native Thai chickens. MATERIAL AND METHODS . The distribution of NPY-ir neurons and fibers in the hen brain was elucidated utilizing immunohistochemical technique. RESULTS . The distributions of NPY-ir neurons and fibers were located throughout the brain, predominantly in the hypothalamus. The numbers of NPY-ir neurons within the nucleus paraventricularis magnocellularis (PVN) were significantly higher than those of the nucleus septalis lateralis (SL), nucleus supraopticus (SOv), and nucleus inferioris hypothalami and nucleus infundibuli hypothalami (IH-IN). In addition, the numbers of NPY-ir neurons within the SL, SOv, and IH-IN were significantly higher than those of the tractus septomesencephalicus and nucleus dorsolateralis anterior thalami. CONCLUSIONS . These results indicated, for the first time, that the distributions of NPY-ir neurons and fibers in the brain of the male native Thai chickens were markedly observed in the hypothalamus, especially within the PVN, implicating that the NPYergic system within the PVN might be related to the regulation of feeding behavior and parental cares in this equatorial species.