Adaptation of pulmonary stretch receptors in different mammalian species

A consequence of the adaptation of pulmonary stretch receptors is that their pattern of discharge depends on both lung volume and its rate of change. For adaptation dependent, flow related information to modify the breathing pattern by a feedback process, appreciable receptor adaptation must take place during a single respiratory cycle. Moreover, for flow related information to have the same significance in all animals, the time course of stretch receptor adaptation would have to vary among species, being more rapid in small animals, with high respiratory frequencies. We recorded single fiber action potentials from 84 pulmonary stretch receptors in six species of mammals, ranging from hamster to dog. The response of the receptors to maintained transpulmonary pressures was similar in the different species,as was the time course of receptor adptation following sudden lung inflations to 5 and 10 cm H2O. These findings show that the behavior of pulmonary stretch receptors is similar in animals with widely differing respiratory frequencies, and that the significance of receptor adaptation for regulation of the breathing pattern must vary interspecifically.