Responses of respiratory modulated and tonic units in the retrotrapezoid nucleus to CO2

摘要: We hypothesized that the retrotrapezoid nucleus (RTN) contains both respiratory modulated (RM) and non-respiratory (NRM) neurons which participate in ventilatory response to increased CO2. made extracellular recordings of activity 46 single units RTN 9 decerebrate, paralyzed, ventilated cats (5 intact; 4 with carotid body sinus ablation) under eucapnic (PCO2 = 34.2±3.5 mmHg; mean ± SD) hypercapnic 47.4 3.4 mmHg) conditions. To define a RM unit, we used η2 statistic is ratio variance unit firing rate within cycles across cycles. classified (N=17) if values eucapnia or hypercapnia were ≥0.25 as NRM (N=29) <0.25. Overall, 19/46 (41%) their CO2, 5 decreased rate, 22 had no significant change rate. Of 17 units, 8 (47%) from 7.6±3.9 23.2±6.8 spikes/sec. These included inspiratory 2 an onset late expiration (Pre-I/I), 1 expiratory unit. Seven these also changed discharge pattern (eucapnic η2=0.02 0.12; η2=0.34 0.79) 29 11 (38%) showed increase CO2 stimulation 19.8±7.2 31.3±82. spikes/sec. The has do medulla pons, it are responsive data indicate some involved central chemoreceptor but they provide direct evidence chemoreception resides RTN.