Neonatal capsaicin treatment decreases airway and pulmonary tissue responsiveness to methacholine.
Am J Physiol
; 266(1 Pt 1): L23-9, 1994 Jan.
Article
em En
| MEDLINE
| ID: mdl-7508200
We studied the effects of selective depletion of neurokinins in sensory nerve fibers by capsaicin treatment on the airway and pulmonary tissue responses to methacholine. Dose-response curves to aerosolized methacholine were performed on anesthetized and mechanically ventilated Wistar rats. Capsaicin (50 mg/kg sc) was administered to 2-day-old rats, and the animals were studied after 12 wk. The response to each dose of methacholine was determined by measuring changes in airway resistance (R(aw)), dynamic pulmonary elastance (Edyn), and pulmonary tissue resistance (Rtis). We calculated sensitivity (Kx) as the concentration of methacholine required for a one-half maximal response and reactivity as the relationship between the maximum response and Kx. Capsaicin treatment resulted in significantly greater values of Kx and lower values of reactivity for R(aw), Edyn, and Rtis compared with control rats. Morphometric analysis of airways showed similar values of the area occupied by smooth muscle but a significantly lower (P < 0.02) area of airway epithelium in capsaicin-treated rats. Our results suggest that methacholine requires capsaicin-sensitive nerves for part of its airway and lung tissue effects.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Brônquios
/
Capsaicina
/
Pulmão
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol
Ano de publicação:
1994
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos