Potassium channels regulate tone in rat pulmonary veins

Evangelos D. Michelakis, E. Kenneth Weir, Xichen Wu, Ali Nsair, Ross Waite, Kyoko Hashimoto, Lakshmi Puttagunta, Hans Gunther Knaus, Stephen L. Archer

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


Intrapulmonary veins (PVs) contribute to pulmonary vascular resistance, but the mechanisms controlling PV tone are poorly understood. Although smooth muscle cell (SMC) K+ channels regulate tone in most vascular beds, their role in PV tone is unknown. We show that voltage-gated (Kv) and inward rectifier (Kir) K+ channels control resting PV tone in the rat. PVs have a coaxial structure, with layers of cardiomyocytes (CMs) arrayed externally around a subendothelial layer of typical SMCs, thus forming spinchterlike structures. PVCMs have both an inward current, inhibited by low-dose Ba2+, and an outward current, inhibited by 4-aminopyridine. In contrast, PVSMCs lack inward currents, and their outward current is inhibited by tetraethylammonimn (5 mM) and 4-aminopyridine. Several Kv, Kir, and large-conductance Ca2+-sensitive K+ channels are present in PVs. Immunohistochemistry showed that Kir channels are present in PVCMs and PV endothelial cells but not in PVSMCs. We conclude that K+ channels are present and functionally important in rat PVs. PVCMs form sphincters rich in Kir channels, which may modulate venous return both physiologically and in disease states including pulmonary edema.

Original languageEnglish (US)
Pages (from-to)L1138-L1147
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number6 24-6
StatePublished - 2001
Externally publishedYes


  • Inward rectifier potassium channels
  • Pulmonary circulation
  • Pulmonary edema
  • Venous tone
  • Voltage-gated potassium channels


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