Role of glycolysis in the tension development under anoxia in guinea pig taenia coli.

The role of glycolysis in the tension development under anoxic conditions in a high-K medium was studied in the intestinal smooth muscle of guinea pig taenia coli. After exposure to the high-K medium (isotonic, 60 mM) under normal oxygen for 30 min, the muscles were exposed to a high-K medium bubbled with N2 gas. The tonic contraction decreased gradually to about 10% of the original level. Glucose was then cumulatively added to the high-K medium under anoxia. The maximum tension was observed following the addition of the higher concentrations of glucose. The muscle tension which developed in the high-K medium with a high concentration of glucose under anoxia was dependent on the external Ca2+ and was inhibited by iodoacetic acid (IAA). The addition of glucose to a high-K medium under anoxia also increased lactate release from the muscle. Pretreatment with 1 mM IAA decreased the lactate release from the muscle. In a Ca2+-free medium under anoxia, the addition of glucose did not increase the muscle tension although there was a significant increase in the lactate release. In summary, it is considered that the smooth muscle of taenia coli develops tension utilizing energy produced by the glycolytic pathway under anoxia in a high-K medium.