Pharmacology 1 2 Aerobic metabolism on muscle contraction in 3 porcine gastric smooth muscle

Exposure to chronic hypoxic conditions causes various gastric diseases, 1 including gastric ulcers. It has been suggested that gastric smooth muscle 2 contraction is associated with aerobic metabolism. However, there are no reports on 3 the association between gastric smooth muscle contraction and aerobic metabolism, 4 and we have investigated this association in the present study. High K+and 5 carbachol (CCh)-induced muscle contraction involved increasing O2 consumption. 6 Aeration with N2 (hypoxia) and NaCN significantly decreased high K+and 7 CCh-induced muscle contraction and O2 consumption. In addition, hypoxia and 8 NaCN significantly decreased creatine phosphate (PCr) contents in the presence of 9 high K+. Moreover, decrease in CCh-induced contraction and O2 consumption was 10 greater than that of high K+. Our results suggest that hypoxia and NaCN inhibit 11 high K+and CCh-induced contractions in gastric fundus smooth muscles by 12 decreasing O2 consumption and intracellular PCr content. However, the inhibition 13 of CCh-induced muscle contraction was greater than that of high K+-induced 14 muscle contraction. 15