Pulmonary stretch receptors

Benzonatate [104-31 ] (46) is a unique compound which appears to have both central and peripheral antitussive effects. Stmcturally it is a derivative of ji)-aminoben2oic acid and contains a long poly(ethylene glycol) side chain. The peripheral effects ate the result of local anesthetic action on the pulmonary stretch receptors. Clinical activity was first reported in 1955 (65). 

Pulmonary stretch receptors are responsible for initiating the Hering-Breuer reflex. These stretch receptors are located within the smooth muscle of large and small airways. They are stimulated when the tidal volume exceeds 1 1. Nerve impulses are transmitted by the vagus nerve to the medullary respiratory center and inhibit the inspiratory neurons. The primary function of these receptors and the Hering-Breuer reflex is to prevent overinflation of the lungs. 

Besides the arterial baroreceptors, central projections from other inputs, for example cardiac mecha-no-receptors, chemo-receptors, pulmonary stretch receptors, and somatic inputs, are capable of influencing the controlling system and thereby the autonomic effectors. 

Meier, Bein, and Helmich (29), and Dawes, Mott, and Widdicombe (30) showed that the pulmonary stretch receptors are excited by the injection of the Veratrum alkaloids, a fact which explains the arrest of breathing caused by injection of suitable doses of these substances. These pulmonary receptors are also excited by veratridine administered as an aerosol (31). 

Matsumoto S, Shimizu T, Kanno T, Yamasaki M, Nagayama T (1990) Elfects of histamine on slowly adapting pulmonary stretch receptor activities in vagotomized rabbits, Jpn J Physiol 40 737-752... 

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