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POMC AND ENDORPHINE ARE INDUCED BY HYPERGRAVITY IN RAT BRAIN.    Y. Kumei¹, H. Shimokawa ², R. Shimokawa³, M. Terasawa², B Linsuwanont², K. Ohya². ¹Dept. of Biochem., ²Dept. of Pharmacol., ³Dept. of Neuropathol., Tokyo Medical and Dental University, Tokyo, Japan. 

The purpose of this study was to observe the hypergravity effects on the brain activity in rats. Wistar male rats of 5-week-age were exposed to 2G by centrifugal rotation for 10 min. Rats were sacrificed with perfusion. Sections were prepared for immuno-histochemistry and in situ hybridiza-tion. Hypergravity induced expression of POMC (proopiomelanocortine) and endorphine in the brain. The POMC gene encodes endorphine. POMC and endorphine was expressed in the arcuate nucleus of the hypothalamus. These histological changes were consistent with behavioral change that was observed as hypergravity-induced analgesia. Gravity change might induce opioid-related reaction in rat. 

 (Supported by NASDA and Japan Space Forum.)