Inspiratory inhibition of pulmonary rapidly adapting receptor relay neurons in the rat.

Second-order relay neurons (referred to as rapidly adapting pulmonary stretch receptors (RARs)-cells) activated by vagal afferents originating from RARs were identified electrophysiologically in Nembutal-anesthetized, paralyzed and artificially ventilated rats. Their location in the commissural subnucleus of the nucleus tractus solitarii (NTS) and firing properties in response to lung inflations and deflations were studied in detail for the first time in the rat. Importantly, in all the RAR-cells examined, their firing was suppressed to various extent during a period from inspiration to early expiration. This means that the information from the RARs to the central nervous system is gated by the central respiratory system at the level of RAR-cells in the NTS.