Effects of anoxia and glucose depletion on isolated veins of the dog.

Canine vein strips were mounted for isometric tension recording. Anoxia did not affect basal tension of saphenous and pulmonary strips mounted in standard Krebs-Ringer solution or after 30 min of incubation in glucose-free solution. Anoxia depressed the strength of spontaneous contractions of mesenteric veins; in glucose-free solution (30 min), anoxia relaxed the strips. Veins placed in glucose-free solution for more than 60 min contracted with anoxia; this contraction was not inhibited by iproveratril. When the vein strips were contracted by norepinephrine or KCl, anoxia depressed the contractions, most in mesenteric and least in saphenous preparations; this depression was greater in the absence of glucose. When oxygen was present, the absence of glucose had little effect on the response to vasoactive agents. Contractions with acetylcholine were depressed by anoxia in mesenteric and pulmonary strips but were augmented in saphenous veins; the latter potentiation was inhibited by iproveratril and by incubation in glucose-free solution. Thus, especially in the saphenous vein, anaerobic glycolysis can provide most of the energy requirements, and intracellular substrates are available for oxidative metabolism.