Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Expression of tyrosine kinase A in the cerebral cortex of postnatal developing rat | J. Vet. Set. 2005 6 3 185-189 JOURNAL OF Veterinary Science Expression of tyrosine kinase A in the cerebral cortex of postnatal developing rat Hyo-Jung Kwon1 Kyoung-Youl Lee2 Il-Kwon Park2 Mi-Sun Park2 Mi-Young Lee2 Moo-Kang Kim2 V cs z V cs z 7 7 cs z cs Incheon Metropolitan Health Environment Research Institute Incheon 404-821 Korea 2College of Veterinary Medicine Chungnam National University Daejeon 305-764 Korea Tyrosine kinase A TrkA is an essential component of the high affinity nerve growth factor NGF receptor necessary to the mediate the biological effects of the neurotrophins NGF. This study examined the distribution of TrkA-immunoreactivity IR cells in the postnatal rat cerebral cortex and the changes that occur in postnatal development as a result of the expression of this protein. TrkA-IR was detected at postnatal day PD 3 PD6 PD9 and PD15. Base upon their somatodendritic morphology the most commonly labeled cell type was the pyramidal neurons. At PD3 and PD6 layer I II III and V was immunopositive for TrkA at PD9 not only at layer I II III and V but also at layer VI. At PD15 the TrkA-positive cells were distributed in all layers. These TrkA-positive cells were not detected at PDO. In contrast there was significant increase in the percentage of cells exhibiting TikA-IR with development and the highest level was detected at PD15. These results suggest that the cerebral cortex expresses TrkA strongly during the postnatal period. Moreover the postnatal development-related increase in the expression of TrkA-cells shows that NGF may have a trophic effect on these cerebral cortex neurons from the postnatal period. Key words cerebral cortex development immunohistochemistry TrkA NGF Introduction Neurotrophins are a group of neurotrophic factors that play an essential role in neuronal development differentiation survival regeneration and function in both the central and peripheral nervous system 16 . This neurotrophin family consists of nerve growth íàctor NGF .
