During their transit through the epididymis, spermatozoa mature and acquire motility and fertilizing capacity. The smooth muscle cells (SMCs) of the epididymal duct are thought to be responsible for the adequate transport of spermatozoa. Thus, precise regulation of SMC function also represents a prerequisite for sperm maturation thereby contributing to male fertility. In this review, we would like to highlight various aspects of epididymal SMC function and discuss several angles with respect to regulation of contraction and relaxation. Different to the vas deferens, where disturbed SMC pathways resulting in male infertility could be defined, comparable information is missing in the epididymis. We therefore include some vas deferens data which could also be useful for a better understanding of epididymal SMC function. Furthermore, we would like to draw attention to drugs used in clinical practice and their potential (side) effects on contractions in the epididymis.
