Release of Acetylcholine from Cultured Cat and Pig Glomus Cells

Abstract

It is generally accepted that neurotransmitters play an essential role in the carotid body chemotransduction. Although roles of each transmitter are in debate, substantial evidence suggests that in cats acetylcholine (ACh) is involved in an excitatory step in the carotid body chemotransduction. The presence of choline acetyl transferase, an ACh-synthesizing enzyme, in glomus cells of cats has been known (Wang et al, 1989). Cholinergic receptors are localized on glomus cells (Dinger et al, 1985, 1986; Chen et al, 1981) and possibly on the carotid sinus nerve (Fitzgerald & Shirahata, 1990). Exogenously applied ACh provokes a fast and clear increase in carotid sinus nerve chemorèceptor discharge (Eyzaguirre et al, 1983; Fidone et al, 1990). Further, perfusion of the carotid body with cholinergic blockers inhibits hypoxia-mediated elevation in chemoreceptor neural activity (Fitzgerald & Shirahata, 1994). However, little is known about the release of ACh from glomus cells. This study was designed to obtain basic information as to the release pattern of ACh from cultured glomus cells.