The effects and mechanism of electrical stimulation on esophageal muscle in rat: an experimental study

Abstract

Objective To explore the correlation between smooth muscle contraction and stimulation parameters, and mechanism of electrical stimulation on the esophageal body muscle strips in normal rats. Methods A segment of lower part esophagus of 20 healthy male WISTAR rats was obtained. Single phase square wave(width 25 ms)was used and the electrical stimulation lasted for 3 s with varied electrical parameter(current: 1.5 V, 3.0 V, 5.0 V, 8.0 V; frequency: 5 Hz, 10 Hz, 20 Hz). The correlation between tension and stimulation parameters was studied.Fifty healthy male rats were divided randomly into control group(n=10), ATR group(n=10), PHT group(n=10), L-NNA group(n=10), TTX group(n=10). Respective drugs were given 10 minutes before lower part of esophagus was stimulated with single phase square wave(5.0 V; 20 Hz; width 25 ms), the tension was recorded and compared among groups. Results At frequency 20 Hz and width 25 ms, the peak value of contraction in 1.5 V group was 0 g. The peak value of contraction in 5.0 V group was more than 3.0 V group and less than 8.0 V group(P 0.1, P 0.1, P 0.05). Conclusion The electrical stimulation of esophageal muscle in normal rats could cause effective contraction immediately. The peak value of contraction is correlated positively with volgage and frequency of electrical stimulation. The effect of electrical stimulation on esophageal muscle is not influenced by nurontransmeters. Key words: Achalasia; Mechanism; Neurotransmitter; Electrical stimulus; Esophageal muscle