Figure 5. DLH-induced dysrhythmia.

A, DLH injection (3 nl, 5 mm) injected at the bar, 300 μm ventral to the dorsal aspect of the VRG and 1 mm caudal to the facial nucleus (preBotC). Upper and middle traces: integrated and raw phrenic nerve activity, respectively. Bottom trace: ABP. Note the DLH-induced very irregular rhythm and pattern on the phrenic nerve. A slight tonic activation of the phrenic nerve is visible on both the raw and integrated traces. B, average T_I, T_E and T_TOT following DLH injection in rats in which dysrhythmia was elicited (n = 13). T_TOT, T_E and T_I are normalized to their control in each animal. DLH injection took place at time = 0. The error bars are much bigger than for the other evoked responses, showing the higher variability in the response for this specific dysrhythmia response. *T_TOT significantly different from control (determined only for measurements made at the peak effect and then at 5 s intervals from 10 to 35 s; P < 0.05).