Characterization of sodium-calcium exchange in rabbit renal arterioles
| Autor: | Beth C. Fowler, Lawrence D. Nelson, P. K. Carmines, P. Darwin Bell |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
medicine.medical_specialty
Afferent arterioles Nigericin Renal glomerulus Efferent Carbazoles chemistry.chemical_element Calcium Ouabain Indole Alkaloids chemistry.chemical_compound Renal Artery Arteriole Internal medicine medicine.artery medicine Extracellular Animals Protein Kinase C Sodium Arterioles medicine.anatomical_structure Endocrinology chemistry Nephrology Biophysics Tetradecanoylphorbol Acetate Female Rabbits medicine.drug |
| Zdroj: | Kidney International. 50:1856-1862 |
| ISSN: | 0085-2538 |
| Popis: | Characterization of sodium-calcium exchange in rabbit renal arterioles. Experiments were performed to test the hypothesis that renal arterioles exhibit Na-Ca exchange capability and that this process is regulated by protein kinase C (PKC). Glomeruli with attached arterioles were dissected from rabbit kidney and loaded with fura-2 for measurement of intracellular calcium concentration ([Ca2+]i) using microscope-based photometry. In tissue bathed in Ringer's solution containing 150mM Na+ and 1.5mM Ca2+, afferent and efferent arteriolar [Ca2+]i averaged 136 ± 6 and 154 ± 7nM, respectively. Removal of extracellular Na+ increased afferent arteriolar [Ca2+]i by 70 ± 7nM, while efferent arteriolar [Ca2+]i only increased by 39 ± 5nM (P < 0.01 vs. afferent arteriole). These responses were inhibited by 6mM Ni2+ and required extracellular Ca2+, but were unaffected by 10µM diltiazem. After incubation in 500µM ouabain, 5 µM monensin, and 5µM nigericin, [Ca2+]i responses to removal of extracellular Na+ were exaggerated significantly, averaging 174 ± 50nM in afferent arterioles and 222 ± 82nM in efferent arterioles (NS vs. afferent arterioles). Moreover, responses to removal of extracellular Na+ were enhanced by 100nM phorbol 12-myristate 13-acetate, an effect which was blocked by PKC inhibition (25nM K252b). These data indicate that both afferent and efferent arterioles express the Na-Ca exchanger, and that PKC activity impacts on exchange capacity in these vessels. |
| Databáze: | OpenAIRE |
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