Hypoxia and Medicine

Why tissue hypoxia and a build-up of vasoactive metabolites dilate arterioles?

Thank you for answers.

Public Comments

1. There are 2 theories for why tissue hypoxia causes vasodialation. The first one suggests that the oxygen sensor detects the partial pressure of oxygen in tissue and responds with feedback release of local mediators such as adenosine, KATP channel activation, eNOS-derived NO, and/or prostacyclin, as well as feed-forward sympathetic activation of ß-adrenergic receptors. The more recent one suggests that hemoglobin's allosteric conformational state serves as the oxygen sensor with the allosteric quaternary structural transition from R (relaxed or oxygenated tetrameric conformation) to T (tense or deoxygenated tetrameric conformation).