Expression and function of the K+ channel KCNQ genes in human arteries

TY - JOUR

T1 - Expression and function of the K+ channel KCNQ genes in human arteries

AU - Ng, Fu Liang

AU - Davis, Alison J

AU - Jepps, Thomas Andrew

AU - Harhun, Maksym I

AU - Yeung, Shuk Yin

AU - Wan, Andrew

AU - Reddy, Marcus

AU - Melville, David

AU - Nardi, Antonio

AU - Khong, Teck K

AU - Greenwood, Iain A

N1 - © 2010 The Authors. British Journal of Pharmacology © 2010 The British Pharmacological Society.

PY - 2011/1

Y1 - 2011/1

N2 - Background and Purpose KCNQ-encoded voltage-gated potassium channels (K v7) have recently been identified as important anti-constrictor elements in rodent blood vessels but the role of these channels and the effects of their modulation in human arteries remain unknown. Here, we have assessed KCNQ gene expression and function in human arteries ex vivo. Experimental Approach Fifty arteries (41 from visceral adipose tissue, 9 mesenteric arteries) were obtained from subjects undergoing elective surgery. Quantitative RT-PCR experiments using primers specific for all known KCNQ genes and immunohistochemsitry were used to show K v7 channel expression. Wire myography and single cell electrophysiology assessed the function of these channels. Key Results KCNQ4 was expressed in all arteries assessed, with variable contributions from KCNQ1, 3 and 5. KCNQ2 was not detected. K v7 channel isoform-dependent staining was revealed in the smooth muscle layer. In functional studies, the K v7 channel blockers, XE991 and linopirdine increased isometric tension and inhibited K + currents. In contrast, the K v7.1-specific blocker chromanol 293B did not affect vascular tone. Two K v7 channel activators, retigabine and acrylamide S-1, relaxed preconstricted arteries, actions reversed by XE991. K v7 channel activators also suppressed spontaneous contractile activity in seven arteries, reversible by XE991. Conclusions and Implications This is the first study to demonstrate not only the presence of KCNQ gene products in human arteries but also their contribution to vascular tone ex vivo.

AB - Background and Purpose KCNQ-encoded voltage-gated potassium channels (K v7) have recently been identified as important anti-constrictor elements in rodent blood vessels but the role of these channels and the effects of their modulation in human arteries remain unknown. Here, we have assessed KCNQ gene expression and function in human arteries ex vivo. Experimental Approach Fifty arteries (41 from visceral adipose tissue, 9 mesenteric arteries) were obtained from subjects undergoing elective surgery. Quantitative RT-PCR experiments using primers specific for all known KCNQ genes and immunohistochemsitry were used to show K v7 channel expression. Wire myography and single cell electrophysiology assessed the function of these channels. Key Results KCNQ4 was expressed in all arteries assessed, with variable contributions from KCNQ1, 3 and 5. KCNQ2 was not detected. K v7 channel isoform-dependent staining was revealed in the smooth muscle layer. In functional studies, the K v7 channel blockers, XE991 and linopirdine increased isometric tension and inhibited K + currents. In contrast, the K v7.1-specific blocker chromanol 293B did not affect vascular tone. Two K v7 channel activators, retigabine and acrylamide S-1, relaxed preconstricted arteries, actions reversed by XE991. K v7 channel activators also suppressed spontaneous contractile activity in seven arteries, reversible by XE991. Conclusions and Implications This is the first study to demonstrate not only the presence of KCNQ gene products in human arteries but also their contribution to vascular tone ex vivo.

KW - Aged

KW - Arteries

KW - Female

KW - Humans

KW - Immunohistochemistry

KW - KCNQ Potassium Channels

KW - Male

KW - Middle Aged

KW - Polymerase Chain Reaction

KW - RNA, Messenger

U2 - 10.1111/j.1476-5381.2010.01027.x

DO - 10.1111/j.1476-5381.2010.01027.x

M3 - Journal article

C2 - 20840535

SN - 0007-1188

VL - 162

SP - 42

EP - 53

JO - British Journal of Pharmacology

JF - British Journal of Pharmacology

IS - 1

ER -