Effect of magnetic stimulation on the electromechanical activity of the rectum: An experimental study

We recently studied the effect of sacral magnetic stimulation (MS) on the r ectal mechanical activity. The current communication investigates its effec t on the rectal electric activity. Twelve mongrel dogs (weight 15.2+/-3.2 k g, 7 male, 5 female) were anesthetized, the abdomen was opened, and three e lectrodes were sutured to the rectal serosa. The rectal pressure was record ed by a manometric catheter. The effect of sacral MS on the rectal electric activity and pressure was recorded before and after anesthetization of the sacral skin. Stimulation parameters were set at 70% intensity, 20 Hz frequ ency, and 1 to 5 s burst activity. Sacral MS of the empty and full rectum e ffected a significant increase of the rectal electric activity and pressure as well as a decrease of the rectal neck (anal canal) pressure. MS of the anesthetized sacral skin produced no significant changes in the rectal elec tromechanical activity or the anal canal pressure. MS of the saline-injecte d sacral skin produced rectal and anal changes similar to those without sal ine injection. In conclusion, MS presumably produces its effect on the rect um by increasing the rectal electric activity. It might provide a more conv enient method for rectal evacuation than electrostimulation through implant ed electrodes. The procedure is simple, easy, and noninvasive.