Measurement of mucociliary clearance from the trachea of conscious and anesthetized rats.

A technique is described whereby particles are injected as a suspension into the trachea of conscious rats. Tracheostomy and cannulation are performed under halothane, but the particles are injected 10 min after recovery. Clearance of BaSO4 particles labeled with 133Ba was determined with a collimated slit gamma-counter, either aligned with the region of particle deposition or used to scan along the animal. Compared with clearance up the trachea in conscous rats, the effect of halothane, thiopental and pentobarbital was to inhibit clearance. With halothane, clearance was resumed at the control rate 0-3 min after anesthesia lasting 7-9 min.