Schweda, Frank and Seebauer, Helga and Kraemer, Bernhard K. and Kurtz, Armin (2001) Functional role of sodium-calcium exchange in the regulation of renal vascular resistance. AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY, 280 (1). F155-F161. ISSN 1931-857X
Full text not available from this repository. (Request a copy)Abstract
Our study aimed to assess a possible functional role of the Na(+)/Ca(2+) exchanger in the regulation of renal vascular resistance (RVR). Therefore, we investigated the effects of an inhibition of the Na(+)/Ca(2+) exchanger either by lowering the extracellular sodium concentration ([Na(+)](e)) or, pharmacologically on RVR, by using isolated perfused rat kidneys. Graded decreases in [Na(+)](e) led to dose-dependent increases in RVR to 4.3-fold (35 mM Na(+)). This vasoconstriction was markedly attenuated by lowering the extracellular calcium concentration, by the L-type calcium channel blocker amlodipine or by the chloride channel blocker niflumic acid. Further lowering of [Na(+)](e) to 7 mM led to an increase in RVR to 7.5-fold. In this setting, amlodipine did not influence the magnitude but did influence the velocity of vasoconstriction. Pharmacological blockade of the Na(+)/Ca(2+) exchanger with KB-R7943, benzamil, or nickel resulted in significant vasoconstriction (RVR 2.5-, 1.8-, and 4.2-fold of control, respectively). Our data suggest a functional role of the Na(+)/Ca(2+) exchanger in the renal vascular bed. In conditions of partial replacement of [Na(+)](e), vasoconstriction is dependent on chloride and L-type calcium channels. A total replacement of [Na(+)](e) leads to a vasoconstriction that is nearly independent of L-type calcium channels. This might be due to an active calcium transport into the cell by the Na(+)/Ca(2+) exchanger.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | IMMORTALIZED AORTIC MYOCYTES; SMOOTH-MUSCLE CELLS; NA+-CA2+ EXCHANGE; NA+/CA2+ EXCHANGE; CYTOSOLIC CA2+; HYPERTENSION; ARTERIOLES; DEPENDENCE; INHIBITION; AMILORIDE; vasoconstriction; benzamil; KB-R7943; nickel |
| Subjects: | 500 Science > 570 Life sciences 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Innere Medizin II Biology, Preclinical Medicine > Institut für Physiologie > Prof. Dr. Armin Kurtz Biology, Preclinical Medicine > Institut für Physiologie > Prof. Dr. Frank Schweda |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 22 Feb 2022 09:37 |
| Last Modified: | 22 Feb 2022 09:37 |
| URI: | https://pred.uni-regensburg.de/id/eprint/41816 |
Actions (login required)
 |
View Item |
