A Model of Reflex Tracheal Constriction in the Dog

Abstract

A tracheal pouch with its nerve and blood supply intact has been prepared in situ in dogs. Mechanical stimulation of the upper airways in dogs anaesthetized with chloralose induced a consistent increase in pouch pressure which was abolished by bilateral vagal section. The response of the pouch following mechanical stimulation of the airways was abolished by intravenous pentobarbitone, atropine, administered systemically or when present in the pouch, and tetracaine, applied to the stimulus area or when present in the pouch. Salbutamol had no inhibitory effects on the response regardless of its route of administration. These results suggest that the increase in pouch pressure following mechanical stimulation of the upper airways is mediated by a vagal reflex arc. The technique may distinguish between drugs the site of action of which is at the afferent or efferent end of this reflex arc.

Influence of a Minimal Surgical Transection around the Trachea on Bronchoconstriction in Cats

“…Data dealing with the effects of vagoto my in animals show that vagus nerves play an important role in the mechanism of the central control of breathing [Glogowska, 1975;Zimmermann and Ulmer, 1977], On the other hand, animal models used to study reflex bronchoconstriction have produced conflicting results [Gold et al, 1972;Krellet al, 1975;Allot et al, 1980;Sant' Ambrogioet al, 1972].…”

Role of the Parasympathetic Cholinergic System in Normal and Obstructed Airways

“…This can be demonstrated by the abo lition of muscle tone and reflex muscle contraction by vagotomy or by atropinic drugs. Figure 1 illustrates an experimental observation [14]. The main question is to what extent other neural pathways modify the cholinergic mechanism.…”