Postnatal Development of Transforming Growth factor-alpha-immunoreactive Neurons in the Diencephalon of the Rat

Park, Young Lan; Kim, Hong Soon; Oh, Jae Wook; Kim, Jong Joong; Moon, Jeong Seok; Jeong, Sang Bong; Chung, Yoon Young

Abstract

Transforming growth factor-alpha (TGF-alpha) immunoreactivity during postnatal development was examined in the rat diencephalon using immunohistochemistry. The time of appearance and localization of TGF-alpha immunoreactivity was slightly different in many areas of diencephalon during postnatal development. At birth, TGF-alpha immunoreactivity was mainly evident in thalamic medial, median and parafascicular thalamic nucleus of intralaminar nuclei. In addition, TGF-alpha immunoreactivity was clearly evident at the first postnatal week in most hypothalamic nuclei. Therefore, TGF-alpha immunoreactivity was found at postnatal days 7 in most diencephalic nuclei excepting the vental posterior thalamic nuclei, metathalamus and epithalamus. The quantitative increase of number was first apparent in the midline structures of thalamus in the first postnatal week. And then TGF-alpha-immunoreactive cells progressively increased throughout diendephalon by postnatal days 15. Adult patterns were reached at postnatal days 20. These results indicate that TGF-alpha-immunoreactive cells were first appeared in thalamic midline structures, increased progressively in the first two postnatal weeks, and followed mediolateral gradient. In addition to maturation of TGF-alpha-immunoreactive cells requires a relatively prolonged period of time to achieve an adult configuration. Also, the early appearance of TGF-alpha immunoreactivity in most diencephalic nuclei may be related to the early appearance of EGFR immunorecativity in many other brain regions. Taken together, these findings suggest that TGF-alpha immunoreactivity correlated with the appearance of the related functional activity in the different regions of diencephalon.