Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Olschewski, A; Hong, Z; Nelson, DP; Weir, EK.
Graded response of K+ current, membrane potential, and Ca2+i to hypoxia in pulmonary arterial smooth muscle.
AMER J PHYSIOL-LUNG CELL M PH 2002 283: L1143-L1150.
Doi: 10.1152/ajplung.00104.2002
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- Führende Autor*innen der Med Uni Graz
- Olschewski Andrea
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- Abstract:
- Many studies indicate that hypoxic inhibition of some K+ channels in the membrane of the pulmonary arterial smooth muscle cells (PASMCs) plays a part in initiating hypoxic pulmonary vasoconstriction. The sensitivity of the K+ current (I(k)), resting membrane potential (E(m)), and intracellular Ca2+ concentration ([Ca2+]i) of PASMCs to different levels of hypoxia in these cells has not been explored fully. Reducing PO2 levels gradually inhibited steady-state I(k) of rat resistance PASMCs and depolarized the cell membrane. The block of I(k) by hypoxia was voltage dependent in that low O2 tensions (3 and 0% O2) inhibited I(k) more at 0 and -20 mV than at 50 mV. As expected, the hypoxia-sensitive I(k) was also 4-aminopyridine sensitive. Fura 2-loaded PASMCs showed a graded increase in [Ca2+]i as PO2 levels declined. This increase was reduced markedly by nifedipine and removal of extracellular Ca2+. We conclude that, as in the carotid body type I cells, PC-12 pheochromocytoma cells, and cortical neurons, increasing severity of hypoxia causes a proportional decrease in I(k) and E(m) and an increase of [Ca2+]i.
- Find related publications in this database (using NLM MeSH Indexing)
- 4-Aminopyridine - pharmacology
- Animals - pharmacology
- Calcium - physiology
- Cell Hypoxia - physiology
- Kinetics - physiology
- Male - physiology
- Membrane Potentials - drug effects
- Muscle, Smooth, Vascular - drug effects
- Peptides - pharmacology
- Potassium Channels - drug effects
- Pulmonary Artery - drug effects
- Rats - drug effects
- Rats, Sprague-Dawley - drug effects
- Research Support, Non-U.S. Gov't - drug effects
- Research Support, U.S. Gov't, Non-P.H.S. - drug effects
- Research Support, U.S. Gov't, P.H.S. - drug effects
- Find related publications in this database (Keywords)
- hypoxic pulmonary vasoconstriction
- patch clamp
- electrophysiology
- ion channels
- oxygen