INTRODUCTION

Male sexual dysfunction is a common medical condition, affecting upward of 31 percent of American men aged eighteen to fifty-nine years (1). Although erectile dysfunction (ED) occupies a prominent position in public interest, largely because of effective pharmacological treatments and national advertising, ejaculatory dysfunction (EjD) is the most prevalent form of male sexual dysfunction, accounting for four times as many affected men as ED (1). Encompassing a broad spectrum of conditions, EjD includes premature ejaculation, anejaculation, and retrograde ejaculation. However, despite the large proportion of men affected, EjD remains poorly studied and understood and does not share the same level of success as the treatment of ED.

PHYSIOLOGY

The male sexual response cycle is composed of four stages: desire, arousal (with erection), orgasm (with ejaculation), and, finally, resolution. The process of ejaculation actually comprises two separate events, emission and expulsion, and occurs separately from orgasm. Emission involves secretion of seminal fluid from the seminal vesicles, prostate, ampulla of vas deferens, and Cowper's glands, along with spermatozoa from the epididymis via the vas deferens. This mixture, now semen, is deposited in the prostatic urethra. Control of emission is primarily modulated by the sympathetic nervous system. Efferent sympathetic nerves from spinal levels T10-L2 emerge to form lumbar sympathetic ganglia, which then continue on to contribute to the superior hypogastric plexus. Postsynaptic adrenergic fibers innervate the prostate, vas deferens, and seminal vesicles.