著者

Miho KANAZASHI Masayuki TANAKA

出版者

Biomedical Research Press

雑誌

Biomedical Research (ISSN:03886107)

巻号頁・発行日

vol.44, no.5, pp.209-218, 2023-09-27 (Released:2023-09-30)

参考文献数

62

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Electrical stimulation (ES) is effective for disuse-induced muscle atrophy. However, the acute effect of ES on muscle protein synthesis (MPS) and muscle protein breakdown (MPB) remains unclear. We investigated the effect of a single-session ES treatment on mTORC1 signaling, MPS, and MPB in the soleus muscle of 2-week hindlimb unloaded rats. Sprague Dawley rats (n = 12 male) were randomly divided into control (CON) and hindlimb unloaded (HU) groups. After 2 weeks, the right soleus muscle was percutaneously stimulated and underwent supramaximal isometric contractions. The left soleus muscle served as an internal control. We collected soleus muscle samples 6 h after ES. Two weeks of HU decreased p70S6K and S6rp activation, downstream factors for mTORC1 signaling, and SUnSET method-assessed MPS, but increased the LC3-II/I ratio, an indicator of autophagy. ES on disused muscle successfully activated mTORC1 signaling but did not affect MPS. Contrary, ES decreased ubiquitinated proteins expression and LC3B-II/I ratio. HU might affect mTORC1 activation and MPS differently in response to acute ES possibly due to excessive ROS production caused by ES. Our findings suggest that ES applied to disused skeletal muscles may suppress MPB, but its effect on MPS appears to be attenuated.

著者

牧野 行雄 塩原 匡貴 村松 久史 川口 貞男 山内 恭 田中 正之 小川 利紘 増谷 浩二 森井 正夫 Yukio Makino Masataka Shiobara Hisafumi Muramatsu Sadao Kawaguchi Takashi Yamanouchi Masayuki Tanaka Toshihiro Ogawa Koji Masutani Masao Morii

雑誌

南極資料 (ISSN:00857289)

巻号頁・発行日

vol.87, pp.1-22, 1985-12

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南極中層大気の総合観測(Antarctic Middle Atmosphere Program)の一環として, 南極昭和基地において1983年3月24日から1984年12月29日まで(第24次および第25次南極地域観測隊)太陽光の赤外分光測定による大気微量成分(N_2O, CH_4,CFCl_3,CF_2Cl_2,HNO_3)の観測を行った。使用した分光計の分解能は最高0.1(cm)^<-1>まで設定可能であるが, 観測時間の長さやS/N比を考慮して0.8(cm)^<-1>で通年観測を行った。延べ111日間に計487個のスペクトルを得たが, これらは最終的に磁気テープに記録し大型電子計算機で処理する。測定されたスプクトルのS/N比から, CFCl_3(850(cm)^<-1>), N_2O(2576(cm)^<-1>), CH_4(6004(cm)^<-1>) のカラム密度は, それぞれ±40,±2,±6%の測定誤差を有することが見積もられる。特に1000(cm)^<-1>域のより精密な測定のために, 今後, 高感度検知器(MCTなど)の安定な使用による観測が望まれる。As part of the Japanese Antarctic Middle Atmosphere Program (Antarctic MAP), columnar amounts of atmospheric minor constituents such as N_2O, CH_4,CFCl_3,CF_2Cl_2 and HNO_3 were determined from measurements of infrared solar spectra for the period 24 March 1983-29 December 1984 at Syowa Station, Antarctica (69°00′S, 39°35′E). A Fourier-transform-infrared spectrometer was used to measure the solar spectra. The highest apodized resolution of the spectrometer is 0.1(cm)^<-1> (full width at half-maximum), but the resolution of 0.8(cm)^<-1> was adopted in routine operation because of an economy of data processing time and of better signal to noise (S/N) ratio. The accuracy of measurements is estimated from S/N ratios of the obtained spectra; typical errors of measured abundances were ±40,±2 and ±6% for CFCl_3 (at 850(cm)^<-1>), N_2O (at 2576(cm)^<-1>) and CH_4 (at 6004(cm)^<-1>), respectively. A MCT detector (cooled at 77 K) is desirable to attain higher resolutions (&acd;0.1(cm)^<-1>) and larger S/N ratios.