Impaired autoregulation of glomerular capillary hydrostatic pressure in the rat remnant nephron.
AUTOR(ES)
Pelayo, J C
RESUMO
In the present micropuncture study, the autoregulation of glomerular capillary hydrostatic pressure (PG) in Munich-Wistar rats 24 h after 75% nephrectomy (Nx) or sham operation (Sh) was investigated. The effect of varying renal perfusion pressure (RPP) on paired determinations of directly measured PG was evaluated in glomeruli of nephrons in which distal fluid delivery was present (unblocked). Autoregulation of PG in Sh glomeruli with unblocked tubules occurred at RPP values between 99.5 +/- 1.0 and 132.1 +/- 1.0 mmHg. In contrast, in Nx glomeruli with unblocked tubules PG increased by 0.32 +/- 0.07 mmHg/mmHg increase in RPP over this same range of RPP (P less than 0.0001). To determine whether enhanced prostaglandins synthesis was responsible for the altered regulation of PG in Nx glomeruli, we repeated the micropuncture measurements in a setting of prostaglandin synthesis inhibition. Although prostaglandins synthesis inhibition did not affect the autoregulation of PG in Sh glomeruli, it did normalize the autoregulatory capacity for PG of Nx glomeruli with unblocked tubules. Thus, acute Nx is associated with a significant loss of the autoregulatory capacity for PG and this impairment appears to be related to a prostaglandin-mediated alteration of the responsiveness of the vascular effector site for autoregulation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=296008Documentos Relacionados
- Ammonia production by individual segments of the rat nephron.
- Clarification of the site of action of chlorothiazide in the rat nephron.
- Distal tubular feedback in the autoregulation of single nephron glomerular filtration rate.
- Angiotensin II binding sites in individual segments of the rat nephron.
- Dietary protein restriction in established renal injury in the rat. Selective role of glomerular capillary pressure in progressive glomerular dysfunction.
