Catecholamine Secretion from Glomus Cells is Dependent on Extracellular Bicarbonate

Abstract

Although an exact understanding of the mechanism of hypoxic transduction in the carotid body has remained elusive, it is generally accepted that the glomus cells play an essential role. These cells synthesize and store neurotransmitters, particularly catecholamines, in dense cored vesicles and release them during hypoxic stimulation. One major theory of hypoxic transduction proposes that hypoxia directly inhibits a K⁺ current leading to depolarization, calcium influx through voltage-dependent channels and enhanced catecholamine secretion secondary to the influx of calcium. Catecholamine, in turn, causes nerve excitation (González et al, 1994).