The interaction between oxygen and vascular wall.
In vascular strips of canine carotid arteries stepwise lowering of oxygen tension from hyperoxic levels of 550 mmHg to 20 mmHg caused in preparations with endothelium a dose-dependent hyperpolarization and relaxation of smooth muscle cells when oxygen tensions between approximately 150 mmHg and 35 mmHg were attained. Pronounced hypoxia with oxygen tensions below 30 mmHg induced a depolarisation and an increase in force generation. During comparable investigations on vessel preparations without endothelium only a slight hyperpolarization and relaxation of the smooth muscle were observed when decreasing the oxygen tension from 550 mmHg to approx. 35 mmHg. In the presence of indomethacin (10(-5) M) a small but significant reduction in the hypoxia-induced hyperpolarization and decrease in smooth muscle tone was found in intact vascular strips with endothelium. Depolarisation and contraction occurred at oxygen tensions below approx. 50-60 mmHg.
Institute of Physiology I, University of Bonn, Germany.
J
J
Grote
G
G
Siegel
K
K
Zimmer
A
A
Adler
D000818:Animals; D002339:Carotid Arteries / Q000502:physiology*; D004285:Dogs; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D010100:Oxygen / Q000097:blood* / Q000494:pharmacology; D010313:Partial Pressure
D010100:Oxygen