Methodologies for studying peripheral O2 chemosensing: Past, present, and future

The reduction of molecular oxygen in individual cells during the process of oxidative phosphorylation is central to oxidative metabolism and bioenergetic homeostasis. As such, any insufficiency in molecular oxygen availability represents a severe threat to sustained life. Thus, as with other similar multicellular organisms, the human body has evolved various peripheral chemosensory pathways that play a key role in sampling arterial PO₂ values and initiating corrective reflex responses so as to maintain homeostasis. Research on these peripheral chemosensors can trace their origins to the cross circulation studies of Corneille Heymans in the early 20th century. Since then, it has become increasingly apparent that defects in these chemosensory pathways play a key role in various pathological conditions, e.g. Sudden Infant Death Syndrome (SIDS), and therefore an understanding of the underlying mechanisms is of critical importance. This review aims to discuss the advantages and disadvantages of the various experimental models employed in studying the mechanisms by which acute peripheral chemosensing occurs.