Anoxia-induced contraction of guinea-pig taenia coli in a glucose-free medium.

The smooth muscle of guinea-pig taenia coli contracted upon exposure to an oxygen deprived glucose-free medium aerated with 95% N2 and 5% CO2. An aeration using 95% O2 and 5% CO2 resulted in an immediate relaxation of the contraction. The anoxia-induced muscle contractions were diminished when the preparations were pretreated with the Ca antagonist D-600. However, the anoxia-induced contractions were not affected by posttreatment with D-600. The 45Ca uptake using the lanthanum method was enhanced at the onset of the anoxia-induced contractions in a glucose-free medium. However, the 45Ca uptake was comparable to control levels in the late phase of anoxia-induced muscle contractions. These results suggest that Ca permeability of cell membranes increases with the onset of an anoxia-induced muscle contraction in glucose-free media.