In:
American Journal of Physiology-Renal Physiology, American Physiological Society, Vol. 290, No. 2 ( 2006-02), p. F542-F549
Abstract:
Expression of cyclooxygenase (COX)-2, but not COX-1, in the renal medulla is stimulated by chronic salt loading; yet the functional implication of this phenomenon is incompletely understood. The present study examined the cellular localization and antihypertensive function of high-salt-induced COX-2 expression in the renal medulla, with a parallel assessment of the function of COX-1. COX-2 protein expression in response to high-salt loading, assessed by immunostaining, was found predominantly in inner medullary interstitial cells, whereas COX-1 protein was abundant in collecting duct (CD) and inner medullary interstitial cells and was not affected by high salt. We compared mRNA expressions of COX-1 and COX-2 in CD vs. non-CD cells isolated from aquaporin 2-green fluorescent protein transgenic mice. A low level of COX-2 mRNA, but a high level of COX-1 mRNA, as determined by real-time RT-PCR, was detected in CD compared with non-CD segments. During high-salt intake, chronic infusions of the COX-2 blocker NS-398 and the COX-1 blocker SC-560 into the renal medulla of Sprague-Dawley rats for 5 days induced ∼30- and 15-mmHg increases in mean arterial pressure, respectively. During similar high-salt intake, COX-1 knockout mice exhibited a gradual, but significant, increase in systolic blood pressure that was associated with a marked suppression of urinary PGE 2 excretion. Therefore, we conclude that the two COX isoforms in the renal medulla play a similar role in the stabilization of arterial blood pressure during salt loading.
Type of Medium:
Online Resource
ISSN:
1931-857X
,
1522-1466
DOI:
10.1152/ajprenal.00232.2005
Language:
English
Publisher:
American Physiological Society
Publication Date:
2006
detail.hit.zdb_id:
1477287-5
