Endothelial KCa1.1 and KCa3.1 channels mediate rat intrarenal artery endothelium derived hyperpolarization response

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  • Estéfano Pinilla
  • Ana Sánchez-Pina, Univ Complutense Madrid, Complutense University of Madrid, Dept Physiol, Fac Pharm, Spanien
  • María Pilar Martínez, Department of Compared Anatomy and Pathological Anatomy, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain., Spanien
  • Mercedes Muñoz Picos, Univ Complutense Madrid, Complutense University of Madrid, Dept Physiol, Fac Pharm, Spanien
  • Albino García-Sacristán, Universidad Complutense de Madrid, Hospital Clínico de San Carlos, Boston University Medical Center, Dept of Physiology, Universidad Complutense de Madrid, Spanien
  • Ralf Köhler, Aragonese Agency for Investigation and Development &, IACS/IIS, Translational Research, Miguel Servet Hospital, Zaragoza, Spain., Spanien
  • Dolores Prieto, Dept. of Physiology, University Complutense, Madrid, Spanien
  • Luis Rivera, Univ Complutense Madrid, Complutense University of Madrid, Dept Physiol, Fac Pharm, Spanien
Aim: Endothelium-derived hyperpolarization (EDH)-mediated response plays an essential role in the control of kidney preglomerular circulation, but the identity of the K+ channels involved in this response is still controversial. We hypothesized that large- (KCa 1.1), intermediate- (KCa 3.1) and small (KCa 2.3) -conductance Ca2+ -activated K+ (KCa) channels are expressed in the endothelium of the preglomerular circulation and participate in the EDH-mediated response.

Methods: We study the functional expression of different K+ channels in non-cultured, freshly isolated native endothelial cells (ECs) of rat intrarenal arteries using immunofluorescence and the patch-clamp technique. We correlate this with vasorelaxant responses ex vivo using wire myography.

Results: Immunofluorescence revealed the expression of KCa 1.1, KCa 3.1 and KCa 2.3 channels in ECs. Under voltage-clamp conditions, acetylcholine induced a marked increase in the outward currents in these cells, sensitive to the blockade of KCa 1.1, KCa 3.1 and KCa 2.3 channels, respectively. Isometric myography experiments, under conditions of endothelial nitric oxide synthase and cyclooxygenase inhibition, showed that blockade either of KCa 1.1 or KCa 3.1 channels was able to reduce the endothelium-derived vasorelaxation of isolated interlobar arteries, while their combined blockade completely abolished it. In contrast, blockade of KCa 2.3 channels did not reduce this vasorelaxant response, despite being functionally expressed in the endothelial cells.

Conclusion: This study shows that KCa 1.1 and KCa 3.1 channels are functionally expressed at the renal vascular endothelium and play a central role in the EDH-mediated relaxation of kidney preglomerular arteries, which is important in the control of renal blood flow and glomerular filtration rate.
TidsskriftActa Physiologica
Antal sider18
StatusUdgivet - apr. 2021

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