Distribution of gastrin-releasing peptide immunoreactivity in the brain ofthe collared dove (Streptopelia decaocto)

The distribution of immunoreactivity after applying an antibody against gas trin-releasing peptide (GRP) was studied in the brain of the collared dove (Streptopelia decaocto). In the forebrain GRP-immunoreactive (GRP-ir) cells were found in the hyperstriatum accessorium, medial and lateral parts of t he neostriatum, corticoidea dorsolateralis and temporoparieto-occipitalis a reas, hippocampus, pre- and parahippocampal areas and prepiriform cortex. i n the brainstem, GRP-ir cells were restricted mainly to the substantia nigr a and ventral tegmental nucleus. Areas with densely packed GRP-ir clusters of varicosities were the medial intermediate hyperstriatum ventrale and lat eral septal nucleus; dense GRP-ir neuropil was found in the parolfactory lo be, and in the dorsal half of the intermediate and caudal archistriatum. Th e ventral lamina medullaris contained many GRP-ir fibers. Forebrain areas d evoid of in immunoreactivity were the basal nucleus, ectostriatum, rostral archistriatum, most of the paleostriatum augmentatum and the lateral bed nu cleus of the stria terminalis, Moderate densities of GRP-ir elements were f ound in the ether telencephalic areas and further in, among others, the pre optic and hypothalamic region, ventral area of Tsai, cerulean nuclei, parab rachial complex, dorsal glossopharyngeal and vagus motor nuclei and medial nuclei of the solitary complex. The observations are compared with data fro m the literature and the implications for the definition of specific center s within the avian brain are discussed, with emphasis on systems with a rol e in visceral and motivational functions and in learning.