Oxygen Tension Sensors in Vascular Smooth Muscle*

Abstract

It is well documented in the literature that mechanical tension in at least some vascular smooth muscle preparations is sensitive to organ bath oxygen tension (1–4). Figure 1 illustrates the O₂sensitivity of in vitrostrips of rabbit aorta as studied by Detar and Bohr (2), who have contributed to the characterization of this phenomenon. PO₂dependent mechanical tension cannot be demonstrated in vascular smooth muscle which does not have spontaneous tension without adding an agonist to produce active tension. Most investigators have studied this phenomenon in arterial strips contracted with catecholamines. Identical PO₂dependent mechanical tension, however, can be demonstrated in rabbit aorta with norepinephrine and with angiotensin contractions (5), suggesting that oxygen sensitivity is not due to effects of oxygen on release, uptake or metabolism of catecholamines.

Supported by HL 10331 and HL 10561 from the National Institutes of Health, Bethesda, Maryland