Cholinergic Aspects of Carotid Body Chemotransduction

Abstract

Neurotransmitters have always been seen as an integral part of the carotid body transducing hypoxia, hypercapnia, and acidosis into increased neural output. Acetylcholine (ACh) was one of the first to be delivered exogenously with a resultant increase in neural output. Hence, ACh was proposed as the principal excitatory neurotransmitter during physiological challenges. A significant amount of data supported this notion, especially studies from Sweden. However, data from other studies was not consistent with this hypothesis. It was reported, for example, that though cholinergic blockers could reduce or abolish an increase in ventilation due to exogenously delivered ACh, they did not block the increase due to hypoxia.