2007 JASN IMPACT FACTOR 7.111	HOME   AUTHOR INFO   EDITORIAL BOARD   SUBSCRIBE   FEEDBACK   ALERTS   HELP
advanced	CURRENT ISSUE	ARCHIVES	JASN Express	ONLINE SUBMISSION

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Koura, Y. Articles by Saruta, T. Search for Related Content PubMed PubMed Citation Articles by Koura, Y. Articles by Saruta, T.

Anandamide Decreases Glomerular Filtration Rate through Predominant Vasodilation of Efferent Arterioles in Rat Kidneys

Yukako Koura^*, Atsuhiro Ichihara^*, Yuko Tada^*, Yuki Kaneshiro^*, Hirokazu Okada, Constance J. Temm, Matsuhiko Hayashi^* and Takao Saruta^*

*Internal Medicine, Keio University School of Medicine, Tokyo, Japan; Internal Medicine, Saitama Medical College, Saitama, Japan; and Medicine, Division of Nephrology, Indiana University, Indianapolis, Indiana

Correspondence to Dr. Atsuhiro Ichihara, Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Phone: +81-3-5363-3796; Fax: +81-3-3359-2745; E-mail: atzichi{at}sc.itc.keio.ac.jp

ABSTRACT. For determining the effects of anandamide (ANA) on renal hemodynamics and microcirculation, a clearance study was performed in Sprague-Dawley rats that received injections of ANA in doses of 15, 150, and 1500 pmol/kg. At doses up to 150 pmol/g, ANA significantly decreased GFR and increased renal blood flow (RBF) without affecting mean arterial pressure (MAP). In the presence of the cannabinoid type 1 (CB1) receptor antagonist AM251, only the 15-pmol/kg dose significantly increased GFR and RBF without altering MAP, with higher doses having no effect on GFR, RBF, or MAP. By contrast, AM281, which antagonizes cannabinoid receptors nonselectively, inhibited the GFR, RBF, and MAP responses to ANA. The arteriolar responses to ANA were also assessed in vitro by the blood-perfused juxtamedullary nephron technique. Higher doses of ANA significantly increased the diameter of both afferent and efferent arterioles, whereas lower doses elicited predominant efferent arteriolar dilation. AM251 attenuated the afferent arteriolar response to ANA and inhibited the efferent arteriolar response to ANA, whereas AM281 inhibited the responses in both arterioles. The CB1 receptor mRNA was expressed in afferent arterioles, and immunohistochemical staining demonstrated the presence of CB1 receptors in both afferent and efferent arterioles. These results suggest that ANA causes afferent arteriolar dilation via both CB1 and non-CB1 receptors and greater efferent arteriolar dilation via CB1 receptors, resulting in a decreased GFR and an increased RBF without affecting MAP.

Copyright © 2008 by the American Society of Nephrology. Online ISSN: 1533-3450 Print ISSN: 1046-6673