| Co-Investigator(Kenkyū-buntansha) |
SAKAI Kiyoshi Faculty of Pharmaceutical Sciences, Kyushu University, 薬学部, 教授 (90153840)
SAKATA Toshiie Faculty of Medicine, Kyushu University, 医学部, 助教授 (50037420)
SHIMIZU Nobuaki Faculty of Medicine, Kyushu University, 医学部, 講師 (50019634)
OOMURA Yutaka Faculty of Science, Kyushu University, 名誉教授 (30019517)
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| Research Abstract |
Three endogenous chemical substances, such as 3,4-dihydroxybutanoic acid (3,4-DB), 2,4,5-trihydroxypentanoic acid (2,4,5-TP) and 2-buten-4-olide (2-B40) were identified in blood under normal conditions of rats. Their concentrations were demonstrated to be increased following food deprivation. Injection of 3,4-DB or 2-B40 into the IIIed ventricle induced anorexia in rats, while injection of 2,4,5-TP provoked feeding behavior. The mechanisms of central actions of these substances were investigated. Intracellular recordings were made from neurons in the lateral hypothalamic area (LHA) and ventromedial hypothalamic nucleus (VMH), brain areas referred to as feeding and satiety centers, respectively. The LHA meurons hyperpolarized by 3,4-DB showed no change in membrane input resistance, while the depolarized VMH neurons were associated with an increase in membrane resistance. The effect of 2-B40 was similar to that of 3,4-DB. 2,4,5-TP depolarized LHA neurons but hyperpolarized VMH neurons with a decrease in the membrane resistance. The results of this study indicated that 3,4-DB and 2,4,5-TP have reciprocal effects on each LHA and VMH neurons, and provide further evidence for the roles of these three chemicals as endogenous feeding modulatory substances.
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