2.　細胞外カルシュウム濃度による微小重力マウス大動脈平滑筋膜電位変動に関する考察 | Extracellular calcium induced aortic smooth muscle cellular membrane current variations in microgravity simulation mice

一般演題

「重力・水浸」

2.　細胞外カルシュウム濃度による微小重力マウス大動脈平滑筋膜電位変動に関する考察

丁　文静^1,3，アニエ　クリステル　ベ^1,3，ジワス　サンチュ^1,3，王　晗²，陳　志斌¹，高　凌峰^2,3，王　楊^2,3

¹海南医学院臨床医学院
²海南医学院医学生理学部
³海南医学院特殊環境生理学実験室

Extracellular calcium induced aortic smooth muscle cellular membrane current variations in microgravity simulation mice

Wenjing Ding^1,3, Annie Christel Bell^1,3, Diwas Sunchuri^1,3, Han Wang², Zhibin Chen¹, Lingfeng Gao^2,3, Yang Wang^2,3

¹Department of Clinical Medicine
²Department of Medical Physiology
³Offshore Medical Physiology Laboratory, Hainan Medical College

【Background】　In microgravity environment, skeleton system is easily demineralization to induce high Ca²⁺ releasing in body fluid （Rambaut 1979;Connors 1985;Oberg 1986;Holick 1992;Heer 1999;Zerwekh 2002;Clément 2011）.　Arterial smooth muscle cells functions are most depending on extracellular calcium concentration, triggers Ca²⁺ induced Ca²⁺ release （CICR）.　We observed aorta smooth muscle preload induced membrane current changes in high calcium iso-osmotic ringer’s solutions in vitro.
　【Method】　Denervation intact smooth muscles were from Kunming mice, 1 week simulates the microgravity by supine head-down tilt position.　Aortic smooth muscle layer that excluded endothelia and adventitia, is fixed on micro stepping device.　Another side is connected to BL-420S biological signal collecting and processing system.　The glass micropipette attached on the smooth muscle to obtain electrical current signals.　The preload stretching induced myogenic spontaneous contraction and membrane current in high Ca²⁺ environment were observed.
　【Results】　1） In microgravity aorta with high Ca²⁺ （14 mmol/L）, stretch prolonged relaxation duration and make a quick response of spontaneous contraction.　DHP Ca²⁺ channel blocker can reduce this kind of spontaneous contractions, suggest Ca²⁺ are main compound to promote spontaneous contractions;2） Normal aorta, high Ca²⁺ induce instantly response of cation influx, however stretch induce delayed membrane response;3） Microgravity aorta delayed the membrane response to high Ca²⁺, while have an instantly response to stretch;4）Stretch induced cation influx may blocked by DHP Ca²⁺ channel blocker, suggest the main compound of cation influx are Ca²⁺.
　【Conclusions】　In microgravity, high Ca²⁺ induces compliance decreasing, promotes a quick membrane response.　This can be improved by Ca²⁺ channel blocker.