Preserved regulation of renal perfusion pressure by small and intermediate conductance KCa channels in hypertensive mice with or without renal failure

• Published in: Pflügers Archiv 2015-04, Vol.467 (4), p.817-831
• Main Authors: Waeckel, Ludovic, Bertin, Florence, Clavreul, Nicolas, Damery, Thibaut, Köhler, Ralf, Paysant, Jérôme, Sansilvestri-Morel, Patricia, Simonet, Serge, Vayssettes-Courchay, Christine, Wulff, Heike, Verbeuren, Tony J., Félétou, Michel
• Format: Article
• Language: English
• Subjects: Angiotensinogen - genetics; Angiotensinogen - metabolism; Animals; Biomedical and Life Sciences; Biomedicine; Cell Biology; Endothelium, Vascular - drug effects; Endothelium, Vascular - metabolism; Endothelium, Vascular - physiology; Female; Human Physiology; Humans; Hypertension, Renovascular - etiology; Hypertension, Renovascular - metabolism; Hypertension, Renovascular - physiopathology; Indomethacin - pharmacology; Intermediate-Conductance Calcium-Activated Potassium Channels - antagonists & inhibitors; Intermediate-Conductance Calcium-Activated Potassium Channels - metabolism; Methacholine Chloride - pharmacology; Mice; Mice, Inbred C57BL; Molecular Medicine; Neurosciences; Nitric Oxide Synthase - antagonists & inhibitors; Organ Physiology; Potassium Channel Blockers - pharmacology; Receptors; Renal Insufficiency - etiology; Renal Insufficiency - metabolism; Renal Insufficiency - physiopathology; Renin - genetics; Renin - metabolism; Small-Conductance Calcium-Activated Potassium Channels - antagonists & inhibitors; Small-Conductance Calcium-Activated Potassium Channels - metabolism; Sodium, Dietary - adverse effects; Vasodilation
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/s00424-014-1542-y

The purpose of this study was to assess, in the murine kidney, the mechanisms underlying the endothelium-dependent control of vascular tone and whether or not, in a severe model of hypertension and renal failure, K Ca channels contribute to its regulation. Wild-type (BL) and double-transgenic female mice expressing human angiotensinogen and renin (AR) genes received either control or a high-salt diet associated to a nitric oxide (NO) synthase inhibitor treatment (BLSL and ARSL). Changes in renal perfusion pressure (RPP) were measured in isolated perfused kidneys. BLSL and AR were moderately hypertensive without kidney disease while ARSL developed severe hypertension and renal failure. In the four groups, methacholine induced biphasic endothelium-dependent responses, a transient decrease in RPP followed by a cyclooxygenase-dependent increase in RPP. In the presence or not of indomethacin, the vasodilatations were poorly sensitive to NO synthase inhibition. However, in the presence of cyclooxygenase and NO synthase inhibitors, apamin, and/or TRAM-34, blockers of K Ca 2.3 and K Ca 3.1, respectively, abolished the decrease in RPP in response to either methacholine or the two activators of K Ca 2.3/K Ca 3.1, NS309, and SKA-31. Thus, K Ca 2/3 channels play a major role in the regulation of murine kidney perfusion and this mechanism is maintained in hypertension, even when severe and associated with kidney damage.