Aerobic metabolism on muscle contraction in porcine gastric smooth muscle

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