[Discharge patterns of respiratory related neurones in the medial areas of nucleus retrofacialis of medulla].

Experiments were performed on rabbits and SD rats, both anesthetized with urethane (1.0 g/kg, i.v. or i.p.). Discharges of phrenic nerve and the diaphragmatic muscle electric activities were monitored. Discharge patterns of the respiration-related neurons (RRNs) in the medial area of nucleus retrofacialis (mNRF) were recorded and analyzed. Among the 249 RRNs recorded in the mNRF of the rabbits, 118 were inspiratory (I, 47.4%), 91 expiratory (E, 36.5%), and 40 phase-spanning (PS, 16.1%). Both I and E neurons could be further subdivided into 4 subtypes, the PS neurons into E-I and I-E type. In the 153 RRNs recorded in rats, 68 were I (44.5%), 55 E (35.9%), 30 PS (19.6%). It was found that a group of E-I PS neurons that fire preceding phrenic nerve respiratory activity are located in the mNRF, which was believed to be important in the generation of the basic respiratory rhythm.