title: Inhibition of rat carotid body glomus cells TASK-like channels by acute hypoxia is enhanced by chronic intermittent hypoxia.
abstract: Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, enhances carotid body (CB) chemosensory responses to acute hypoxia. In spite of that, the primary molecular target of CIH in the CB remains unknown. A key step of the hypoxic response in the CB is the chemoreceptor cell depolarization elicited by the inhibition of K(+) channels. Thus, we tested the hypothesis that CIH potentiates the hypoxic-induced depolarization of rat CB chemoreceptor cells by enhancing the inhibition of a background K(+) TASK-like channel. Membrane potential, single channel and macroscopic currents were recorded in the presence of TEA and 4-aminopyridine in CB chemoreceptor cells isolated from adult rats exposed to CIH. The CIH treatment did not modify the resting membrane properties but the hypoxic-evoked depolarization increased by 2-fold. In addition, the hypoxic inhibition of the TASK-like channel current was larger and faster in glomus cells from CIH-treated animals. This novel effect of CIH may contribute to explain the enhancing effect of CIH on CB oxygen chemoreception.
authors.affiliation: Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile.
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Ortiz
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Del Rio
authors.forename: German
authors.initials: G
authors.lastname: Ebensperger
authors.forename: Victor R
authors.initials: VR
authors.lastname: Reyes
authors.forename: Julio
authors.initials: J
authors.lastname: Alcayaga
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Varas
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Iturriaga
mesh_terms: D000818:Animals; D002344:Carotid Body / Q000378:metabolism*; D002628:Chemoreceptor Cells / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology; D007150:Immunohistochemistry; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D009419:Nerve Tissue Proteins; D018408:Patch-Clamp Techniques; D024683:Potassium Channels, Tandem Pore Domain / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020181:Sleep Apnea, Obstructive / Q000378:metabolism / Q000503:physiopathology
chemical_list: D009419:Nerve Tissue Proteins; D024683:Potassium Channels, Tandem Pore Domain; C420132:potassium channel subfamily K member 3