Differences in the spinal command of ejaculation in rapid ejaculating rats.
BACKGROUND
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.


OBJECTIVE
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.


METHODS
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
Aren J
AJ
Pelvipharm Laboratories, Orsay, France. aren.borgdorff@gmail.com
Rössler
Anne-Sophie
AS
Clément
Pierre
P
Bernabé
Jacques
J
Alexandre
Laurent
L
Giuliano
François
F
D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D004542:Ejaculation; D004558:Electric Stimulation; D004576:Electromyography; D005837:Genitalia, Male / Q000294:innervation*; D008297:Male; D009119:Muscle Contraction; D051381:Rats; D017208:Rats, Wistar; D012726:Sexual Behavior, Animal; D012735:Sexual Dysfunction, Physiological; D013116:Spinal Cord; D018709:Statistics, Nonparametric; D013997:Time Factors