Oviductal Ovum Surrogate Movement: Interrelation with Muscular Activity11

Abstract

Oviducts were removed from rabbits 68 h after an injection of human chorionic gonodotropin to induce ovulation and were placed in a lucite organ bath through which oxygenated Tyrodes'' solution (pH 7.1) flowed continuously at a temperature of 37.degree. C. A surrogate ovum was placed 1-2 cm into the fimbrial end of the oviduct, and electrodes placed on the surface of the circular muscle in the region of the ampullary-isthmic-junction (AIJ). When the surrogate reached the recording site (which generally took 5-15 min), its location relative to the electrodes was observed through a dissecting microscope. Muscular activity of the AIJ and distal isthmus oviduct apparently contributes directly to movement of spheres within the lumen. Lack of obvious dire directionality in the propagation of electrical activity in the rabbit and human oviducts, together with the present data showing rapid motion in the ovarian and uterine directions, provides support for the hypothesis that ovum transport is a dimensional random walk with reflecting and absorbing barriers at the ovarian and uterine ends of the oviduct, respectively.