title: Two types of glomus cell in the rat carotid body as revealed by alpha-bungarotoxin binding.
abstract: Horseradish peroxidase (HRP)-conjugated alpha-bungarotoxin (alpha Bgt) was used to localize alpha Bgt-acetylcholine receptor sites in the rat carotid body. Two types of glomus cell were differentiated on the basis of the staining of their plasma membranes by the conjugate: type A, devoid of staining or only partly stained; and type B, exhibiting staining over the entire cell surface. The parts of type A glomus and supporting cells stained were always in direct apposition to type B glomus cells. It is concluded that type B glomus cells are possibly the only cell types exhibiting specific binding sites of alpha Bgt. Other morphological characteristics and quantitative studies indicated that the type A and type B glomus cells presented in this study were equivalent to those described in the rat carotid body by other investigators (McDonald & Mitchell, 1975). alpha Bgt-HRP staining facilitated the observation of the distribution pattern of glomus cells in the parenchyma: type A glomus cells were arranged in groups and often showed polarity toward neural elements and sinusoidal capillaries; and clusters of type B glomus cells were frequently situated in a demilune -like fashion over groups of type A glomus cells. Because of differences in morphology, synaptology, alpha Bgt-binding affinity, and polarity toward the blood vessels, we propose that type A and type B glomus cells in the rat carotid body represent functionally distinct cell types.
mesh_terms: D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000378:metabolism; D001665:Binding Sites; D002038:Bungarotoxins / Q000378:metabolism*; D002344:Carotid Body / Q000166:cytology* / Q000502:physiology; D006651:Histocytochemistry; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission
chemical_list: D002038:Bungarotoxins; D000109:Acetylcholine