Fig. 2

Changes of CSNDF and CVNDF in rabbits with different treatment at different time after HCl aspiration. a, changes of CSNDF in rabbits after HCl aspiration; b, changes of CVNDF in rabbits after HCl aspiration. For control group (n = 8), rabbits only received saline intratracheally injection (2.8 ml/kg) after surgery; for HCl groups (n = 8), ALI model was established by intratracheal injection of HCl (pH 1.5, 2.8 ml/kg); for VNS groups (n = 8), after the ALI model established by HCl, rabbits also received constant voltage stimuli (5 V, 2 ms, and 1 Hz); for THA group (n = 8), after ALI model established by HCl, rabbits also received THA (3 mg/kg) intravenous injection; and for SGB group, after ALI model established by HCl, rabbits also continuously received 0.25% bupivacaine pumping via epidural catheter (3 mg/kg). CSNDF, cervical sympathetic nerve discharge frequency; CVNDF, cervical vagus nerve discharge frequency; VNS, vagus nerve stimulation; THA, tetrahydroaminoacridine; SGB, stellate ganglion block; ALI, acute lung injury