[Alternation of regulation system for pulmonary arterial tone in pulmonary hypertension].
In pulmonary artery smooth muscle cells(PASMC), the Ca-influx required for myogenic tone is mainly supplied through the L-type Ca channels, which sustained open around resting membrane potential. Therefore, the voltage-gated K channels, which determine membrane potential in PASMC, are critical for regulation of the Ca-influx and myogenic tone. The voltage-gated K channels are inhibited in hypoxic condition. The inhibition may be related to the hypoxic pulmonary vasoconstriction and the chronic hypoxia-induced pulmonary hypertension. In subjects with primary pulmonary hypertension, the voltage-gated K channels are also inhibited. On the other hand, the Ca-activated K channels of PASMC are also inhibited in chronic exposure with pulmonary hypertension. The reduction of the K channels in pulmonary hypertension may enhance proliferation of PASMC.
Tohse
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Department of Physiology, Sapporo Medical University School of Medicine.
D002455:Cell Division / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000503:physiopathology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*; D014661:Vasoconstriction
D015221:Potassium Channels