Figure 8.

In vivo experimental preparation. A, A schematic of the in vivo experimental preparation which includes concurrent diaphragm (DIA) and GG EMG recordings in lightly anesthetized rats. For details, see Materials and Methods. High-frequency spikes in the diaphragm EMG are EKG artifacts. B, Example trace showing diaphragm and GG EMG and the rectified and integrated GG EMG. After uninterrupted baseline recordings, a 15-s nasal occlusion was administered (indicated by square). The distance between the onset of nasal occlusion and the first discernable GG muscle EMG burst (arrow) is defined as onset latency. C, D, EMG amplitude was normalized as a percentage of the largest burst recorded during nasal occlusion (see Materials and Methods). At P1–P5, GG EMG amplitude during nasal occlusion was not different between control (closed circles) and eDNE (open squares) pups (C); however, by P10–P12, eDNE animals had a significantly blunted amplitude response compared with control animals (D). At P1–P5, onset latency of GG EMG bursts was not different between control and eDNE pups (E). However, by P10–P12, onset latency of GG EMG bursts was significantly longer in eDNE pups compared with control pups. Data derived from n = 8 control pups and n = 8 eDNE pups in each age group. All data presented as mean ± SD; * indicates significant difference between control and eDNE.