Endothelin 1 (ET-1) seems essential in salt-dependent hypertension, and activation of ETA receptors causes renal vasoconstriction. However, the response in the renal medulla and the role of tissue NO availability has never been adequately explored in vivo. We examined effects of ETA and ETB receptor blockade (atrasentan and BQ788) on blood pressure (MAP), medullary blood flow (MBF) and medullary tissue NO. Effects of systemic and intramedullary blocker application were compared in anesthetized normotensive ET-1-pretreated Sprague-Dawley rats (S-D), in salt-dependent hypertension (HS/UNX) and in spontaneously hypertensive rats (SHR). Total renal blood flow (RBF) was measured using a Transonic renal artery probe, MBF as laser-Doppler flux, and tissue NO signal using selective electrodes. In normotensive rats ET-1 significantly increased MAP, decreased RBF (-20%) and renal medullary NO. In HS/UNX rats atrasentan decreased MAP and increased medullary NO, earlier and more profoundly with intravenous infusion. In SHR atrasentan decreased MAP, more effectively with intravenous infusion; the increase in tissue NO (∼10%) was similar with both routes; however, only intramedullary atrasentan increased MBF. No consistent responses to BQ788 were seen. We confirmed dominant role of ETA receptors in regulation of blood pressure and renal hemodynamics in normotensive and hypertensive rats and provided novel evidence for the role of ETA in control of intrarenal NO bioavailability in salt-dependent and spontaneous hypertension. Under conditions of activation of the endothelin system ETB stimulation preserved medullary perfusion.

• MeSH
• antagonisté endotelinového receptoru A farmakologie   terapeutické užití   MeSH
• antagonisté endotelinového receptoru B farmakologie   terapeutické užití   MeSH
• antihypertenziva farmakologie   terapeutické užití   MeSH
• atrasentan farmakologie   terapeutické užití   MeSH
• eliminace ledvinami účinky léků   MeSH
• endotelin-1 farmakologie   terapeutické užití   MeSH
• hemodynamika účinky léků   MeSH
• hypertenze farmakoterapie   metabolismus   MeSH
• krevní tlak účinky léků   MeSH
• ledviny účinky léků   metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• oligopeptidy farmakologie   terapeutické užití   MeSH
• oxid dusnatý metabolismus   MeSH
• piperidiny farmakologie   terapeutické užití   MeSH
• potkani inbrední SHR MeSH
• potkani Sprague-Dawley MeSH
• receptor endotelinu A účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH