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Intrarenal artery injection of capsaicin activates spontaneous activity of renal afferent nerve fibers

Ma Huiiuan, Wu Yuming, Ma Huijie, Zhang Lihua, He Ruirong

Department of Physiology, Institute of Basic Medicine, Hebei Medical University. Shijiazhuang 050017,China

Abstract

The effects of intrarenal artery injection of capsaicin on multi- and single-unit spontaneous discharges of renal afferent nerve fibers were investigated in anesthetized rabbits. The results obtained are as follows: (1) intrarenal artery injection of capsaicin (20, 40, and 60 nmol/kg) increased the renal afferent nerve activity (ARNA) in a dose-dependent manner with unchanged arterial pressure; (2) pretreatment with ruthenium red (40 mmol/kg), a capsaicin receptor antagonist, completely abolished the effect of capsaicin; and (3) pretreatment with a nitric oxide synthase inhibitor L-NAME ( N6-nitro-L-arginine methylester, 0.1 mmol/kg), significantly enhanced the ARNA response to capsaicin. The results suggest that intrarenal artery injection of capsaicin can activate ARNA via capsaicin receptors in anesthetized rabbits and that nitric oxide may be involved in regulating the activity of renal sensory nerve fibers as an inhibitory neurotransmitter.

Key words: Capsaicin;Renal afferent nerve;Unit-activity;Ruthenium red ;L-NAME

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Citing This Article：

Ma Huiiuan, Wu Yuming, Ma Huijie, Zhang Lihua, He Ruirong. Intrarenal artery injection of capsaicin activates spontaneous activity of renal afferent nerve fibers . Acta Physiol Sin 2003; 55 (5): (in Chinese with English abstract).