Byung Joo Kim1, Jae Yeoul Jun, Insuk So, Ki Whan Kim. 1. Department of Physiology and Biophysics, College of Medicine, Seoul National University, 28 Yongon-Dong, Chongno-Gu, Seoul 110-799, Republic of Korea.
Abstract
AIM: Interstitial cells of Cajal (ICCs) are the pacemaker cells that generate slow waves in the gastrointestinal (GI) tract. We have aimed to investigate the involvement of mitochondrial Na+-Ca2+ exchange in intestinal pacemaking activity in cultured interstitial cells of Cajal. METHODS: Enzymatic digestions were used to dissociate ICCs from the small intestine of a mouse. The whole-cell patch-clamp configuration was used to record membrane currents (voltage clamp) and potentials (current clamp) from cultured ICCs. RESULTS: Clonazepam and CGP37157 inhibited the pacemaking activity of ICCs in a dose-dependent manner. Clonazepam from 20 to 60 micromol/L and CGP37157 from 10 to 30 micromol/L effectively inhibited Ca2+ efflux from mitochondria in pacemaking activity of ICCs. The IC50s of clonazepam and CGP37157 were 37.1 and 18.2 micromol/L, respectively. The addition of 20 micromol/L NiCl2 to the internal solution caused a "wax and wane" phenomenon of pacemaking activity of ICCs. CONCLUSION: These results suggest that mitochondrial Na+-Ca2+ exchange has an important role in intestinal pacemaking activity.
AIM: Interstitial cells of Cajal (ICCs) are the pacemaker cells that generate slow waves in the gastrointestinal (GI) tract. We have aimed to investigate the involvement of mitochondrial Na+-Ca2+ exchange in intestinal pacemaking activity in cultured interstitial cells of Cajal. METHODS: Enzymatic digestions were used to dissociate ICCs from the small intestine of a mouse. The whole-cell patch-clamp configuration was used to record membrane currents (voltage clamp) and potentials (current clamp) from cultured ICCs. RESULTS:Clonazepam and CGP37157 inhibited the pacemaking activity of ICCs in a dose-dependent manner. Clonazepam from 20 to 60 micromol/L and CGP37157 from 10 to 30 micromol/L effectively inhibited Ca2+ efflux from mitochondria in pacemaking activity of ICCs. The IC50s of clonazepam and CGP37157 were 37.1 and 18.2 micromol/L, respectively. The addition of 20 micromol/L NiCl2 to the internal solution caused a "wax and wane" phenomenon of pacemaking activity of ICCs. CONCLUSION: These results suggest that mitochondrial Na+-Ca2+ exchange has an important role in intestinal pacemaking activity.
Authors: Bernard T Drumm; Tae S Sung; Haifeng Zheng; Salah A Baker; Sang D Koh; Kenton M Sanders Journal: Cell Calcium Date: 2018-02-01 Impact factor: 6.817