[Impulse activity of slowly adapting pulmonary receptors during respiration].

Impulse activity of 50 pulmonary slow-adapting receptors (SAR) has been investigated in anesthetized cats during eupnea under conditions of quasi-static and dynamic lung inflation. During inspiration 74% SARs were found to have nonlinear relationship between the receptor frequency (F) and pulmonary volume (V), in 16% receptors the F-V relationship was linear. Impulse activity of 10% SARs had different characteristics. During quasi-static inflation 40% SARs had the nonlinear F-V relationship, 50% SARs had the linear one. During dynamic inflation 70% SARs had the nonlinear F-V relationship, 20% SARs had the linear one. The F-V relationship of the afferent output from all investigated SARs was nonlinear during eupnea. Differences in the F-V relationships of SARs during lung inflation and eupnea as well as possible synaptic connections of SARs with bulbar respiratory neurons are discussed.