Muscular Activity in the Rabbit Oviduct: A Combination of Electric and Mechanic Recordings1

Abstract

A method is described by which muscular activity of the rabbit oviduct can be recorded in detail. Spontaneous electric activity and intraluminal pressure were simultaneously recorded in vitro in the oviducts of five ovariectomized, estrogen-treated rabbits. Electric activity was examined by five suction electrodes placed on the surface of the oviduct. Intraluminal pressure of the isthmus was recorded during perfusion at constant flow rates of 1.4, 2.9, and 5.8 µl/min. Perfusion at these low rates did not increase the electric activity of the isthmus by stretch. The main pacemaker was localized on a discrete area around the ampullary-isthmic junction (AIJ). The mean frequency of electric discharges was 3.6 ± 1.6/mm (mean ± SD) in the AIJ and 1.6 ± 1.2/min in the ampulla. From the AIJ electric activity spread through the entire isthmus, at a velocity of 17 ± 2 mm/sec, and it always preceded the pressure cycles. The mean perfusion pressure was 4 ± 2 mm Hg, the amplitude of the pressure cycles 19 ± 2 mm Hg, their duration 6.2 ± 1.2 sec, and their maximum rate of rise 26 ± 7 mm Hg/sec, at the perfusion rate of 5.8 µl/min. The luminal diameter of the resting isthmus was calculated to be less than the diameter of eggs.