Biomaterial Database

Endogenous angiotensin II inhibits natriuresis after acute volume expansion in the neonatal rat. 1996

R L Chevalier, and B A Thornhill, and D C Belmonte, and A J Baertschi

Department of Pediatrics, University of Virginia, Charlottesville 22908, USA.

Compared with the adult, the neonatal renal natriuretic response to acute volume expansion (VE) is attenuated. To test the hypothesis that antinatriuresis is mediated by endogenous angiotensin I (ANG II), Sprague-Dawley rats were given losartan, an ANG II type 1 (AT1)-receptor inhibitor (40 mg.kg-1.day-1) from birth to 14-17 days. Control littermates received saline vehicle. Anesthetized rats underwent acute saline VE for measurement of mean arterial blood pressure (MAP), plasma aldosterone concentration (Paldo), plasma atrial natriuretic peptide (PANP), glomerular filtration rate (GFR), sodium excretion (UNaV), potassium excretion (UKV), and urine guanosine 3',5'-cyclic monophosphate excretion (UcGMPV). Losartan increased basal urine flow fivefold, UNaV 10-fold, and UKV twofold. Acute VE induced marked diuresis, natriuresis, and kaliuresis in the losartan but not in the saline group. This occurred without change in Paldo and PANP and despite lower MAP, GFR, and UcGMPV. In addition, losartan did not affect release of cGMP from isolated glomeruli stimulated by ANP or sodium nitroprusside. We conclude that the limited renal response to acute VE in the neonate results from stimulation of tubular Na reabsorption by ANG II acting on the AT1 receptor.

UI	MeSH Term	Description	Entries
D007093	Imidazoles	Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).
D008297	Male		Males
D009318	Natriuresis	Sodium excretion by URINATION.	Natriureses
D010952	Plasma Substitutes	Any liquid used to replace blood plasma, usually a saline solution, often with serum albumins, dextrans or other preparations. These substances do not enhance the oxygen- carrying capacity of blood, but merely replace the volume. They are also used to treat dehydration.	Blood Expanders,Plasma Volume Expanders,Expanders, Blood,Expanders, Plasma Volume,Substitutes, Plasma,Volume Expanders, Plasma
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D004231	Diuresis	An increase in the excretion of URINE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Diureses
D005919	Glomerular Filtration Rate	The volume of water filtered out of plasma through glomerular capillary walls into Bowman's capsules per unit of time. It is considered to be equivalent to INULIN clearance.	Filtration Rate, Glomerular,Filtration Rates, Glomerular,Glomerular Filtration Rates,Rate, Glomerular Filtration,Rates, Glomerular Filtration
D006400	Hematocrit	The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.	Erythrocyte Volume, Packed,Packed Red-Cell Volume,Erythrocyte Volumes, Packed,Hematocrits,Packed Erythrocyte Volume,Packed Erythrocyte Volumes,Packed Red Cell Volume,Packed Red-Cell Volumes,Red-Cell Volume, Packed,Red-Cell Volumes, Packed,Volume, Packed Erythrocyte,Volume, Packed Red-Cell,Volumes, Packed Erythrocyte,Volumes, Packed Red-Cell
D000804	Angiotensin II	An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.	Angiotensin II, Ile(5)-,Angiotensin II, Val(5)-,5-L-Isoleucine Angiotensin II,ANG-(1-8)Octapeptide,Angiotensin II, Isoleucine(5)-,Angiotensin II, Valine(5)-,Angiotensin-(1-8) Octapeptide,Isoleucine(5)-Angiotensin,Isoleucyl(5)-Angiotensin II,Valyl(5)-Angiotensin II,5 L Isoleucine Angiotensin II,Angiotensin II, 5-L-Isoleucine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia