Differences in the Spinal Command of Ejaculation in Rapid Ejaculating Rats
Article first published online: 8 MAY 2009
© 2009 International Society for Sexual Medicine
The Journal of Sexual Medicine
Volume 6, Issue 8, pages 2197–2205, August 2009
How to Cite
Borgdorff, A. J., Rössler, A.-S., Clément, P., Bernabé, J., Alexandre, L. and Giuliano, F. (2009), Differences in the Spinal Command of Ejaculation in Rapid Ejaculating Rats. Journal of Sexual Medicine, 6: 2197–2205. doi: 10.1111/j.1743-6109.2009.01308.x
- Issue published online: 27 JUL 2009
- Article first published online: 8 MAY 2009
- Premature Ejaculation;
- Ejaculation Latency;
- Spinal Generator for Ejaculation
Introduction. It has been hypothesized that lifelong premature ejaculation is part of a biological variation in the intravaginal ejaculation latency, but what causes this variation remains poorly understood.
Aim. The aim of this study is to elucidate whether variations in ejaculation latencies in an experimental rat model for premature ejaculation are linked to differences in the spinal command of ejaculation.
Main Outcome Measures. Electrical microstimulation of the spinal generator for ejaculation revealed an accelerated expulsion phase in rapid ejaculating rats.
Methods. Adult male Wistar rats were categorized as “sluggish,”“normal,” or “rapid” ejaculators on the basis of their ejaculation frequency in sexual mating tests. One to three weeks after selection, males were urethane anesthetized and electrically microstimulated in the spinal generator for ejaculation, evoking ejaculation. Bulbospongiosus muscle electromyographic and intraluminal vas deferens pressure were measured simultaneously, representing, respectively, the expulsion and emission phase in ejaculation.
Results. Electrical microstimulation of the spinal generator for ejaculation evoked ejaculation in “sluggish” (N = 9), “normal” (N = 13), and “rapid” (N = 11) ejaculating rats. Vas deferens contraction (emission phase) was evoked at different stimulation strengths, but response properties were not statistically different between “sluggish,”“normal,” and “rapid” ejaculator rats. Bulbospongiosus muscle contractions (expulsion phase) following microstimulation was significantly accelerated in “rapid” rats as compared with “sluggish” and “normal” rats. The total duration of bulbospongiosus muscle contractions remained unchanged between the three ejaculator groups.
Conclusions. Our results provide the first scientific evidence supporting a neurophysiological difference between “rapid,”“normal,” and “sluggish” ejaculators, expressed as an accelerated expulsion phase in “rapid” ejaculator rats. This bridges the gap between a sexual behavior trait and the spinal command of ejaculation. Borgdorff A, Rössler A-S, Clément P, Bernabé J, Alexandre L, and Giuliano F. Differences in the spinal command of ejaculation in rapid ejaculating rats. J Sex Med 2009;6:2197–2205.