title: Hidden function of neuronal nicotinic acetylcholine receptor beta2 subunits in ganglionic transmission: comparison to alpha5 and beta4 subunits.
abstract: Neuronal nicotinic acetylcholine receptors (nAChR), which modulate fast excitatory postsynaptic potentials (f-EPSP), are located on both pre- and postganglionic sites in the autonomic nervous system (ANS). The receptor subunits alpha3, alpha5, alpha7, beta2 and beta4 are present in autonomic ganglia in various combinations and modulate acetylcholine (ACh) transmission. In the present study, autonomic functions were systemically examined in mice lacking beta2 subunits (beta2-/-) to further understand the functional role of beta2 subunits in modulating ganglionic transmission. The results show normal autonomic functions, both under physiological conditions and in perturbed conditions, on thermoregulation, pupillary size, heart rate responses and ileal contractile reactions. This suggests that the function of beta2-containing receptors in ganglionic transmission is hidden by the predominant beta4 containing receptors and confirms previous studies which suggest that alpha3alpha5beta4 nAChRs are sufficient for autonomic transmission. On the other hand, beta2-containing receptors have only a minor function on postsynaptic responses to ACh, but may modulate ACh release presynaptically, although there is no evidence for this.
authors.affiliation: Department of Physiology and Pharmacology, Sackler Medical School, Tel Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Ningshan
authors.initials: N
authors.lastname: Wang
authors.forename: Avi
authors.initials: A
authors.lastname: Orr-Urtreger
authors.forename: Joab
authors.initials: J
authors.lastname: Chapman
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Ergün
authors.forename: Ruth
authors.initials: R
authors.lastname: Rabinowitz
authors.forename: Amos D
authors.initials: AD
authors.lastname: Korczyn
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D018723:Bethanechol / Q000494:pharmacology; D001833:Body Temperature Regulation / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D019706:Excitatory Postsynaptic Potentials / Q000235:genetics / Q000502:physiology*; D005725:Ganglia, Autonomic / Q000378:metabolism*; D006339:Heart Rate / Q000235:genetics; D018738:Hexamethonium / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D015877:Miosis / Q000235:genetics; D009474:Neurons / Q000378:metabolism*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010277:Parasympathomimetics / Q000494:pharmacology; D010528:Peristalsis / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics / Q000502:physiology; D011978:Receptors, Nicotinic / Q000235:genetics / Q000502:physiology*; D009435:Synaptic Transmission / Q000235:genetics / Q000502:physiology*; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology
chemical_list: D000109:Acetylcholine; D018723:Bethanechol; D018738:Hexamethonium; D018733:Nicotinic Antagonists; D010277:Parasympathomimetics; D021122:Protein Subunits; D011978:Receptors, Nicotinic