Noninvasive superfusion of canine tracheal segment to study prostaglandin release in vivo

To be able to study the release of mediators from the canine trachea noninvasively in vivo, we modified an endotracheal tube to allow superfusion of the lumen of an isolated segment of trachea. We tested this apparatus by measuring prostaglandin E2 (PGE2) output in the presence and absence of a stimulant (bradykinin) and a blocker (indomethacin) and comparing the results with results of in vitro studies. We found that PGE2 output increased with time over the 180 min of the study. Bradykinin (10(-5) M) applied to the luminal surface increased PGE2 output markedly. Indomethacin (10(-5) M) decreased PGE2 and prevented the usual increase in PGE2 caused by bradykinin. These findings are qualitatively similar to those for in vitro experiments. We conclude that this apparatus can be used to measure the release of mediators from the trachea of dogs noninvasively in vivo.