The effect of alternating current stimulation on the esophageal motility of rabbits

Abstract

Objective To observe the effect of electrical stimulation on the movement of rabbits esophagus, and to promote effective esophageal peristalsis and determine the best electrical pacing parameters. Methods After anesthesia, 24 healthy rabbits underwent open surgery and the lower esophagus was exposed. The esophagus was stimulated with the multi-channel signal generator, and the changes of esophagus pressure and the length of esophageal contraction with high resolution manometry were recorded.(1) The effects on contraction pressure of esophagus body and lower esophageal sphincter (LES) after single site electrical stimulation under different parameters were observed.The stimulation modes utilized were electric current 3 mA, 5 mA and 8 mA, frequency 5 Hz, 10 Hz and 20 Hz, pulsewidth 0.25 ms, 25 ms and 50 ms, waveform of single phase and double phase.(2)The esophagus was sequentially stimulated. The stimulation mode utilized was electric current 5 mA, frequency 20 Hz, pulsewidth 25 ms, stimulation duration 3 s, single phase square wave. Results At electrical stimulation on the esophagus body and LES, contraction delay was 13.00±1.54 ms and 12.00±0.73 ms respectively. The contraction pressure of esophageal body was significantly positively related tothe electric current (R=0.968, P<0.01), the pulse width(R=0.971, P<0.01), and the frequency (R=0.947, P<0.01). The length of contraction in 10 Hz group was shorter than that of the 20 Hz group(1.33±0.06 cm VS 1.80±0.00 cm, P<0.05). The contraction pressure of LES was also significantly positively related to the electric current(R=0.965, P<0.01), the pulse width (R=0.973, P<0.01), and the frequency (R=0.842, P<0.01). The pressure of lower esophageal sphincter of single phase square wave was greater than that of the double phase square group (P<0.05). Under the same parameters, the contraction pressure of LES group was lower than that of the esophageal body group (27.33±1.15 mmHg VS 104.00±6.00 mmHg, P<0.05). Esophageal sequential contraction was induced by multi-points sequential electrical stimulation. Conclusion Single point electric stimulation can cause esophageal contraction immediately without obvious delay. Within a certain range, the esophageal contraction pressure is positively correlated with electric current, frequency and pulse width. The contraction pressure of single square phase wave is greater than that of the double square phase wave. The contraction pressure of esophageal body is greater than that of LES after electric stimulation. Multi-points sequential electrical stimulation can promote sequential movement of esophagus. Key words: Electrostimulation; Achalasia; Gastroesophageal reflux; High resolution manometry; Low esophageal sphincter