Electroejaculation of the great apes

Abstract

The scientific literature concerning electroejaculation of simian primates contains many reports of successful collection of seminal fluid through electrostimulation with penile and rectal electrodes. In none of these reports is there a sufficient discussion of the important electrical parameters involved, such as the amplitude and density of electric current and the impedance of the electrode/tissue interface. Without such information it is difficult, if not impossible, for investigators in other laboratories to duplicate the stimulation regimen successfully and without injury to the animal. This assumes even greater importance when such techniques are considered for application to human beings.

Following a series of unsuccessful experiments employing nonsinusoidal waveforms with penile, perineal, and suprapubic electrodes, we designed and constructed three rectal probes which enabled us to define two directed (with respect to the rectal axis) current patterns: longitudinal current and circular current. We also monitored and made careful measurements of the stimulating current and the electrode/tissue interface impedance during experiments leading to emission of seminal fluid.

The probe designed for circular current stimulation has permitted semen collections from eight chimpanzees, two orangutans, and four lowland gorillas, a collective total of 59 out of 67 attempts. Several interesting drug-related observations were made linking inhibition of ejaculation with administration of atropine and phenothiazine compounds.