Effect Of Erythromycin And Azithromycin On Sensation Afferent Nerve Functions Of Gastrointestinal Tract And Heart Rate Variability

AIM: To investigate the effect of erythromycin and azithromycin on sensation afferent nerve functions of gastrointestinal tract and the effect of erythromycin on sympathovagal balance.METHODS:1. Sixty-four Sprague-Dawley rats were randomly divided into erythromycin group, azithromycin group, control group, low dose group (0.1 mg/kg), medium dose group (0.5mg/kg) and high dose group (1 mg/kg). Spontaneous afferent nerve discharge and gastric distention-induced afferent nerve discharge of subdiaphragmatic vagus nerve were recorded before and half an hour after intravenous injection of different doses of erythromycin and azithromycinin.2. 32 Adult Sprague-Dawley rats were randomly divided into control group, erythromycin group(low dose group 25 mg/kg, medium dose group 50mg/kg,and high dose group 100 mg/kg). ECG was recorded and RR interval was extracted for HRV analyzing through a personal computer online before and half an hour after intravenous injection of different doses of erythromycin. HRV results were gain after analyzing: Mean of heart period(Mhp), mean heart rate(Mhr), RR interval standard deviation (Hsd), The relative dispersion(Hrd), Lyapunov exeponent(Hle), fractal dimension (Hfd), and Chaosness(Hcc), ultralow frequency band power 0.003-0.04Hz (absolute value APU, relative magnitude RPU), low frequency band power 0.04-0.14Hz(absolute value APL, relative magnitude RPL), high frequency band power 0.14-0.5Hz(absolute value APH, relative magnitude RPH), total power(TPV), APU/APH and APL/APH (RUH, RLH).RESULTS:1. Intravenous 0.1 mg/kg erythromycin and azithromycin had no significant effect on spontaneous afferent nerve discharge and gastric distention-induced afferent nerve discharge of subdiaphragmatic vagus nerve after 20 min. Intravenous 0.5mg/kg and 1 mg/kg erythromycin and azithromycin had significant effect on spontaneous afferent nerve dis-chargeand gastric distention-induced afferent nerve discharge of subdiaphragmatic vagus nerve which was compared with the control and low dose groups (p<0.05).2. Intravenous 25 mg/kg erythromycin had no obvious effect on HRV after 10 min. Intravenous 50mg/kg and 100 mg/kg erythromycin dose had significant effect on HRV after 10 min, (parameters Mhp/Hsd/ Hrd/ Hfd/ APU/APL/APH/RPU/RUH/RLH/TPV increased, Mhr/Hcc/RPH decreased), which was compared with the control and low dose groups (P<0.05).CONCLUSION:1. Erythromycin and azithromycin have significant effects on sensation afferent nerve functions of gastrointestinal tract in rats.2. Erythromycin has significant effects on sympathovagal balance.