TY - JOUR AU - YE Chun-ling AU - SHEN Bing AU - REN Xian-da AU - LUO Rong-jing AU - DING Sheng-yuan AU - YAN Fu-man AU - JIANG Jia-hua PY - 2016 TI - An increase in opening of BK(Ca) channels in smooth muscle cells in streptozotocin-induced diabetic mice JF - Acta Pharmacologica Sinica; Vol 25, No 6 (June 2004): Acta Pharmacologica Sinica Y2 - 2016 KW - N2 - AIM: To investigate the changes of function of large conductance of calcium-activated potassium channels (BK(Ca) channels) in thoracic aortic smooth muscle cells in early stage of streptozotocin (STZ)-induced diabetic C57BL/6J mice. METHODS: Vascular muscle tension in the isolated thoracic aortic rings of mice was compared, and the role of BK(Ca) channels in relaxation of isolated mice thoracic aortic rings induced by acetylcholine (ACh) was determined. Meanwhile, single vascular smooth muscle cells (VSMCs) were isolated by collagenase, and BK(Ca) currents were recorded by patch-clamp single channel recording technique in symmetric high potassium solution. RESULTS: Tetraethylammonium (TEA) 1 mmol/L, a selective calcium-activated potassium channel blocker, caused significant rightward shift in the concentration-response curves of ACh in the isolated thoracic aortic rings of diabetic mice and pD2 value of ACh-induced relaxation was decreased notably after TEA treatment [(6.3+/-0.4) vs (6.9+/-0.5), n=10 rings from 7 mice, P 0.05]. Furthermore, conductance of BK(Ca) channels in single thoracic aortic smooth muscle cells was decreased [(199+/-15) pS, n=10 cells from 7 mice vs (266+/-11) pS, n=12 cells from 6 mice, P<0.01], but probability of open of BKCa channels was increased [(0.51+/-0.28) vs (0.11+/-0.06), n=6 cells from 6 mice, P<0.01], and the mean closed time in diabetic mice was reduced [(15+/-15) vs (132+/-98), n=6 cells from 6 mice, P<0.05]. CONCLUSION: The opening of BK(Ca) channels was increased in thoracic aortic smooth muscle cells in the early stage of STZ-induced diabetic C57BL/6J mice by reducing mean closed time, but the conductance of BK(Ca) channels was decreased. UR - http://www.chinaphar.com/article/view/8210