HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 102/6/2201    most recent 01436.2006v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Peng, W. Articles by Xu, F. Search for Related Content PubMed PubMed Citation Articles by Peng, W. Articles by Xu, F.

Respiratory syncytial virus infection in anesthetized weanling rather than adult rats prolongs the apneic responses to right atrial injection of capsaicin

Pathophysiology Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico

Submitted 18 December 2006 ; accepted in final form 14 March 2007

Apnea is a common complication in infants infected by respiratory syncytial virus (RSV). A recent study has shown that intranasal inoculation of RSV in conscious weanling rats strengthens the apneic responses to right atrial injection of capsaicin (CAP), leading to 66% mortality. The objectives of the present study were to determine 1) whether RSV infection changes baseline minute ventilation (E) and arterial blood gases in anesthetized rats; 2) what the effects of RSV infection are on the respiratory responses to CAP; and 3) whether the RSV-strengthened apneic responses are age dependent. Our experiments were conducted in anesthetized and spontaneously breathing rats divided into four groups of weanling and adult rats that received either intranasal inoculation of RSV or virus-free medium. Two days after RSV infection (0.7 ml/kg), animal blood gases, baseline E, and E responses to right atrial injection of three doses of CAP (4, 16, and 64 µg/kg) were measured and compared among the four groups. Our results showed that RSV infection increased respiratory frequency (25%, P < 0.05) in weanling but not adult rats, with little effect on arterial blood gases. RSV infection amplified the apneic responses to CAP in weanling but not adult rats, characterized by increases in the initial (40%) and the longest apneic duration (650%), the number of apneic episodes (139%), and the total duration of apneas (60%). These amplifications led to 50% mortality (P < 0.05). We conclude that RSV infection increases respiratory frequency and strengthens the apneic responses to CAP only in anesthetized weanling but not adult rats.

age; hypoxia; upper airway infection; bronchopulmonary C fibers