Hypoxic Modulation of the Cholinergic System in the Cat Carotid Glomus Cell
The carotid body is a primary sensory organ for arterial hypoxia. Chemosensory glomus cells in the carotid body release neurotransmitters, including ACh, in response to hypoxia. The release of neurotransmitters from the glomus cell, a putative chemoreceptor cell, appears to be triggered by an influx of calcium and subsequent increase in intracellular calcium ([Ca2+]i). Several reports indicate that L-type and some other types of voltage-gated calcium channels are responsible for neurotranmitter release from glomus cells (Gonzalez et al., 1994). These channels are activated by depolarization of the cell membrane. However, the speed and the degree of depolarization in glomus cells may not be sufficient to activate voltage-gated Ca2+ channels at mild hypoxia (Chou et al., 1998), where afferent neural activity from the carotid body starts increasing. This discrepancy led us to search for other mechanisms which elevate [Ca2+]i followed by neurotransmitter release.
KeywordsNicotinic Receptor Carotid Body Krebs Solution Cholinergic Agonist Glomus Cell
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- Chou C.-L., Schofield B., Sham J.S.K., Shirahata M., 1998, Electrophysiological and immunological demonstration of cell-type specific responses to hypoxia in the adult cat carotid body, 789: 229–238.Google Scholar