Video microscopy as a tool to visualize cGMP effects on contractility and sperm transport in seminiferous tubules and the epididymal duct

Background Peritubular contractile cells within the testis and epididymis surround seminiferous tubules and the epididymal duct. These cells are crucial for the transport of sperm which only acquire motility and fertilizing capacity during transit from the testis to the distal epididymal duct. cGMP contributes to regulate smooth muscle cell function [1,2]. The role of cGMP, cGMP-hydrolysing PDE5 and potential effects of the PDE5 inhibitor sildenafil in testicular and epididymal smooth muscle cells, however, remains largely unknown despite the expanding use of sildenafil to treat erectile dysfunction and pulmonary hypertension.