Nitric oxide mediates capsaicin-induced increase in cochlear blood flow

Zoltán Vass, P. Bradley Brechtelsbauer, Alfred Nuttall, Josef M. Miller

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Capsaicin has been previously shown to increase cochlear blood flow (CBF) in a dose-dependent manner. The aim of this study was to define the role of nitric oxide (NO) in capsaicin-induced changes in CBF. This was investigated in the anesthetized guinea pig, utilizing laser Doppler flowmetry. Application of capsaicin (64.8 and 6.48 nmol in 2 μl of saline) to the round window membrane (RWM) caused increases in CBF (34 ± 2.8% of baseline (BL) and 28 ± 2.3% BL. respectively (P <0.001)). Application of the NO synthase inhibitor. N(G)-nitro-L-arginine methyl ester (L-NAME) (10 mg/kg intravenously or topically to the RWM) reduced blood flow in the cochlea, as previously reported. After pretreatment with i.v. L-NAME, the effect of capsaicin on CBF was significantly decreased. With the dose of capsaicin at 64.8 nmol, the increase in CBF fell from 34 ± 2.8% BL to 6.9 ± 1.5% BL (P <0.001), and at 6.48 nmol it fell from 28 ± 2.3% BL to 4.8 ± 1.6% BL (P <0.001). RWM L-NAME application also decreased the capsaicin vasodilatation effect. A capsaicin dose of 64.8 nmol resulted in only a 10 ± 2.5% BL increase in CBF, and with 6.48 nmol capsaicin the increase was 7.8 ± 2.2% of BL (P <0.001). Capsaicin-sensitive sensory neurons in other systems are generally known to release substance P (SP), which in turn elicits release of endothelium derived relaxing factor (NO). The results of this study indicate that NO is a mediator of capsaicin-sensitive sensory neuronal function in CBF regulation.

Original languageEnglish (US)
Pages (from-to)114-119
Number of pages6
JournalHearing Research
Volume100
Issue number1-2
DOIs
StatePublished - Oct 1996

Fingerprint

Capsaicin
Cochlea
Nitric Oxide
NG-Nitroarginine Methyl Ester
Membranes
Endothelium-Dependent Relaxing Factors
Laser-Doppler Flowmetry
Sensory Receptor Cells
Substance P
Vasodilation
Nitric Oxide Synthase
Guinea Pigs

Keywords

  • capsaicin
  • guinea pig
  • inner ear
  • laser Doppler flowmetry
  • nitric oxide
  • sensory neuron
  • substance P

ASJC Scopus subject areas

  • Sensory Systems

Cite this

Nitric oxide mediates capsaicin-induced increase in cochlear blood flow. / Vass, Zoltán; Brechtelsbauer, P. Bradley; Nuttall, Alfred; Miller, Josef M.

In: Hearing Research, Vol. 100, No. 1-2, 10.1996, p. 114-119.

Research output: Contribution to journalArticle

Vass, Zoltán ; Brechtelsbauer, P. Bradley ; Nuttall, Alfred ; Miller, Josef M. / Nitric oxide mediates capsaicin-induced increase in cochlear blood flow. In: Hearing Research. 1996 ; Vol. 100, No. 1-2. pp. 114-119.
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