Intrarenal artery injection of capsaicin activates spontaneous activity of renal afferent nerve fibers.
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 (N(6)-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.
Ma
Hui-Juan
HJ
Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017.
Wu
Yu-Ming
YM
Ma
Hui-Jie
HJ
Zhang
Li-Hua
LH
He
Rui-Rong
RR
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005260:Female; D007269:Injections, Intra-Arterial; D007668:Kidney / Q000294:innervation*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology; D011817:Rabbits; D012430:Ruthenium Red / Q000494:pharmacology; D017833:Visceral Afferents / Q000502:physiology*
D012430:Ruthenium Red; D009569:Nitric Oxide; D002211:Capsaicin; D019331:NG-Nitroarginine Methyl Ester