The transduction properties of tracheal stretch receptors in vitro.

Extrathoracic tracheal stretch receptors and tracheal tension were recorded in vitro when the trachea was stretched. The receptors responded to an increase in tension produced by displacement in the longitudinal or transverse axis of the trachea. They were sensitive to the rate of change of tension as well as the tension level itself, i.e. there was a dynamic component in the response. A fall in temperature decreased discharge frequency but the receptors were not affected by changes in PCO2 and pH of the perfusion fluid. Contraction of tracheal muscle, induced by acetylcholine, increased discharge frequency showing that the receptors studied were effectively in series with the muscle.