Morphological study of neuropeptide Y immunoreactive neurons (NPY-IR) of telencephalon in developing chick

Lee, Mee Young; Park, Il Kwon; Lee, Kyoung Youl; Kwon, Hyo Jung; Park, Mee Sun; Kim, Moo Kang; Lee, Kang Iee; Jung, Young Gil

Abstract

Neuropeptide Y (NPY) was a 36-amino acid peptide that biochemical structure to be resemble the pancreatic polypeptide in mammalian and it was first isolated from porcine brain by Tatemoto et al. (1982). It is now known to neurotransmitter or neuromodulator as well as it has important effects to sexual precocity, regulation of feeding behavior and function of pituitary gland in avians. The distribution and morphological study of NPY-immunoreactive neurons (NPY-IR) is studied in many experimental animal but in developing chick brain have been not studied. The present study provided the distribution and morphological study of NPY-IR in developing chick brain. The developing brain of Korean native chicks embryos at E8, E10, E12, E14, E16, E18, and E20 days of incubation were used. Experimental animals were perfused with 4% paraformaldehyde through the left ventricle and aorta. The brains were removed and transferred 30% sucrose, and then cut on a cryostat into 60 mm-thick. The tissue immunostained with free-floating and avidin-biotin complex (ABC) method. The results obtained in this study are that followings. The numerous of NPY-IR first observed at E8 days in the telencephalon of neostriatum, ectostriatum, archistriatum intermedium pars ventralis, nucleus taeniae and paleostriatum agumentatum, at E12 days in telencephalon of hippocampus, at E14 days in telencephalon of hyperstriatum. In the telencephalon, NPY-IR distributed predominantly in neostriatum and ectostriatum. shape of neuron's that E8 days of incubation were oval shape neurons and increased days of chicks was sphere, oval and many multigonal shapes. Their processes were also omnidirectional. The process of neuron's that E8 days of incubation was observed a few and weak immunity and increased days of chicks was numerous and strong immunity. According to increasing the days the morphology of NPY-IR showed the tendency to increase their sizes and numbers. We suggest that the regional differences in the distribution of NPY-containing neuron types may reflect adaptations of local neuronal circuits for specialized functions.