Exp Neurobiol 2003; 12(2): 105-109

Published online December 31, 2003

© The Korean Society for Brain and Neural Sciences

The Expressional Changes of Nicotinamide Adenine Dinucleotide Phosphate-Diaphorase and Neuronal Nitric Oxide Synthase in the Rat Cerebral Cortex and Hypothalamus during Food Restriction

Kyounglan Kang1, Chan Park2, Ryo Won Choue1, Heekyung Ahn2, In Surk Jang3, Jung Sik Cho4, Ki Soon Shin2 and Youngbuhm Huh2,*

1Department of Medical Nutrition, Graduate School of East-West Medical Science, 2Department of Anatomy, College of Medicine, Kyunghee University, Seoul, Korea, 3Department of Animal Science, Chinju National University, Jinju, Korea 4Department of Laboratory Animal Resources, National Institute of Toxicological Research, KFDA, Seoul, Korea

Correspondence to: *To whom correspondence should be addressed.
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In the present study, we investigated the changes in the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity and neuronal nitric oxide synthase (nNOS) expression during food restriction in the rat cerebral cortex and hypothalamus. The rats were placed on a restricted feeding schedule consisting of half the ad libitum quantity for 1, 2, 4, 6 and 9 weeks, and a free feeding schedule for 1 week. The loss of body weight peaked at 1 week after food restriction and persisted during the entire 9-week period of food restriction. In the hypothalamus, the NADPH-d activity and nNOS immunoreactivity were found to be significantly higher at 1 week and gradually decrease thereafter. In contrast, in the cerebral cortex, the optical densities of the NADPH-d- and nNOS-positive neurons were not changed significantly during the period of food restriction. Our study provides evidence that food restriction has a significant effect on the nitric oxide synthesizing system of the hypothalamus. This suggests a possibility for the relative functions of the nNOS-positive neurons after food restriction.

Keywords: Neuronal nitric oxide synthase, NADPH-diaphorase, hypothalamus, cerebral cortex, food restriction