Effects of chronic resistive airway loading on behavioral changes in rats.

Complete vascular ring is a term describing a group of congenital aortic arch abnormalities that is often observed in infancy and leads to tracheoesophageal compression and airway obstruction. We investigated the effects of chronic resistive airway loading on anxiety and learning behavior in Wistar rats. The trachea were obstructed by a circumferential tracheal band to increase respiratory esophageal pressure. All of the rats were subjected to the elevated plus-maze test and the active avoidance test at 2 or 4 weeks after the obstruction surgery. One set of rats received surgical relief of the tracheal obstruction on week 2 or 3 after obstruction. At 4, but not 2, weeks after tracheal obstruction, the rats showed impairment of learning in the active avoidance test and this impairment was prevented by surgical relief of tracheal obstruction performed on week 2, but not week 3. In contrast, anxiety-like behavior in the elevated plus-maze test was not affected at either 2 or 4 weeks after tracheal obstruction. Body weight was not affected by tracheal obstruction and no differences were seen in arterial blood gases after 4 weeks of tracheal obstruction. These results suggest that chronic tracheal obstruction causes learning deficits and that surgical intervention is necessary and should be performed as early as possible to prevent long-term sequelae.