title: The role of ion channels in hypoxic pulmonary vasoconstriction.
abstract: Hypoxic pulmonary vasoconstriction (HPV) is an important mechanism by which localized flow of blood in small resistance pulmonary arteries is matched to alveolar ventilation. This chapter discusses the role of several potassium and calcium channels in HPV, both in enhancing calcium influx into smooth muscle cells (SMCs) and in stimulating the release of calcium from the sarcoplasmic reticulum, thus increasing cytosolic calcium. The increase in calcium sensitivity caused by hypoxia is reviewed in Chapter 19. Particular attention is paid to the activity of the L-type calcium channels which increase calcium influx as a result of membrane depolarization and also increase calcium influx at any given membrane potential in response to hypoxia. In addition, activation of the L-type calcium channel may, in the absence of any calcium influx, cause calcium release from the sarcoplasmic reticulum. Many of these mechanisms have been reported to be involved in both HPV and in normoxic contraction of the ductus arteriosus.
authors.affiliation: VA Medical Center, 1 Veterans Drive, 111C, Minneapolis, MN, 55417, USA. weirx002@maroon.tc.umn.edu
authors.forename: E Kenneth
authors.initials: EK
authors.lastname: Weir
authors.forename: Jésus A
authors.initials: JA
authors.lastname: Cabrera
authors.forename: Saswati
authors.initials: S
authors.lastname: Mahapatra
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Peterson
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Hong
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D004373:Ductus Arteriosus / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism*; D008168:Lung / Q000098:blood supply* / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism; D011652:Pulmonary Circulation / Q000502:physiology; D014661:Vasoconstriction / Q000502:physiology*
chemical_list: D007473:Ion Channels; D010100:Oxygen; D002118:Calcium