スポーツ ヒダイシン ト ビョウテキ ヒダイシン デワ シュジュ ノ イデンシ ノ ハツゲン ヨウシキ ガ コトナル : ラット デノ ケントウ

Intence exercise causes decrease in expression of both endothelial NO synthase and tissue NO_X level in hearts. Am J Physiol Regulatory Integrative Comp Physiol 279:R951-R959, 2000. -Cardiac myocytes produce nitric oxide (NO). We studied the effects of intense exercise on the expression of NO synthase (NOS) and the tissue level of nitrite (NO^-_2)/nitrate (NO^-_3) (i.e.,NOx), which are stable end products of NO in the heart. Rats ran on a treadmill for 45min. Immediately after this exercise, the heart was quickly removed. Control rats remained at rest during the same 45-min period. The mRNA level of endothelial NOS (eNOS) in the heart was markedly lower in the exercised rats than in the control rats. Western blot analysis confirmed downregulation of eNOS protein in the heart after exercise. Tissue NOx level in the heart was singnificantly lower in the exercised rats than in the control rats. The present study revealed for the first time that prosuction of NO in the heart is decreased by intense exercise. Because NO attenuates positive inotropic and chronotropic responses to β_1-adrenergic stimulation in the heart, the decrease in cardiac production of NO by intense exercise may contribute to the acceleration of increase in myocardial contractility and heart rate during intense exercise.Thesis (Ph. D. in Medical Sciences)--University of Tsukuba, (A), no. 3195, 2003.3.25Includes bibliographical referencesJoint authors: Takashi Miyauchi ... et alOffprint. Originally published in: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, v. 281, pp. R2029-R2036, 2001Includes supplementary treatisesPhysiological and pathological cardiac hypertrophy induce different molecular phenotypes in the rat ~ Iemitsu,M/Miyauchi,T/Maeda,S/Sakai,S/Kobayashi,T/Fujii,N/Miyazaki,H/Matsuda,M/Yamaguchi,