Sensitivity of the renal medullary circulation to plasma vasopressin.
Am J Physiol
; 271(3 Pt 2): R647-53, 1996 Sep.
Article
em En
| MEDLINE
| ID: mdl-8853387
Studies were carried out to determine the effects of physiological changes of plasma arginine vasopressin (AVP) on blood flow distribution in the renal cortex and medulla. Acute decerebration was performed so that studies could be carried out within the low physiological range of circulating AVP. Changes of renal cortical and medullary microcirculatory blood flow were measured with implanted optical fibers and laser-Doppler flowmetry, and total renal blood flow was measured with transit-time ultrasonography. During intravenous infusion of increasing doses of AVP, when plasma AVP was increased in steps from 2.9 to 11.2 pg/ml by intravenous infusion, mean arterial pressure (98 +/- 3 mmHg), total renal blood flow (8.2 +/- 0.6 ml. min-1.g kidney-1), and blood flow in the microcirculation of the cortex (2.11 +/- 0.28 V) remained unchanged, whereas that in the renal medulla decreased progressively. Medullary flow was significantly reduced when circulating levels of AVP increased from a control level of 2.8 to 5.0 pg/ml. The reductions of medullary flow were accompanied by parallel increases of urine osmolality. These data indicate that the vessels supplying the renal medullary circulation are sensitive within the range of plasma AVP concentrations observed with moderate water restriction. The medullary circulation exhibits a sensitivity AVP that parallels that found in the medullary collecting ducts.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Circulação Renal
/
Arginina Vasopressina
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos