Ejaculatory Response Induced by Potassium Chloride in Small Mammals

Abstract

Artificial ejaculation in laboratory animals has been produced by electrical stimulation and by drug action, the latter consisting of a hypnotic followed by a stimulant. No clear description of the properties of the secretions obtained has been reported, nor has either method been described as capable of producing a complete ejaculation containing sperm as well as secretions from the accessory organs of reproduction. A high incidence of ejaculation occurs in the final convulsions of a dying animal. Loewe(l) has termed this phenomenon terminal ejaculation in contrast to intravital ejaculation which neither coincides with death nor is followed by death after a short interval of time. Potassium chloride has been found to produce an intravital ejaculation in mice following intraperitoneal injection of sub-lethal doses. This investigation was undertaken to determine the mechanism by which the ejaculations were induced and the nature of the secretions.

Methods. The animal species employed were the albino mouse, albino rat (Wistar), hamster, guinea pig, pigeon, and ground squirrel. All animals used were adult males. The ground squirrels were trapped by snaring in the vicinity of Lafayette, Ind., and were kept in captivity about 6 months prior to their use. Other animals were obtained from breeders. Chemical agents were administered by intraperitoneal injection into the lower quadrant of the abdomen. Ejaculation time was measured from the time of injection until the first appearance of seminal fluid at the penis. Weights of ejaculates were made by collection on weighed glass microscope slides. Fructose analyses were made by the colorimetric method of Roe as modified by Mann(2). Seminal vesicles were removed through a midline incision in the abdomen cephalad the base of the penis. Isolated seminal vesicles were used to test the in vitro action of chemical agents by the method described by Stone and Loew(3). A seminal vesicle, placed in a bath of oxygenated Locke's solution to which 1.0% dextrose had been added, was attached to a lever writing on a slowly moving kymograph. Chemical test agents were added directly to the bath.