Regulation of Rat Caput Epididymidis Contractility by Prostaglandins

Abstract

Mechanical activity of the rat caput epididymidis in vitro was recorded using a videomicrography system. The effects of prostaglandin (PG)F2α, PGE2, and aspirin on caput epididymidis contractility were determined by measuring the frequency of contraction, luminal diameter, and amplitude of contraction at various concentrations of each test compound in vitro. PGF2α stimulated contractility of the tubules at physiological concentrations, while PGE2 reduced contractility. Aspirin strongly inhibited contractility at concentrations of 10−3 and 10−2 M. Endogenous levels of PGF2α and PGE were determined for rat testes, caput, corpus, and cauda epididymidis and vas deferens. While the concentrations of PGE were consistently higher than those of PGF2α, both compounds were relatively low in the testes, high in the vas deferens, and intermediate throughout the epididymis. Results from these experiments strongly suggest that PGs are important regulators of proximal epididymidis contractions and thus may regulate sperm transport through that organ.

Regulation of Spontaneous Contractile Activity in the Bovine Epididymal Duct by Cyclic Guanosine 5′-Monophosphate-Dependent Pathways

“…The predominant PG synthesized by this COXisozyme seems to be PGE 2 , which was found to reduce contraction in the epididymal caput of the rat (52). In contrast, in the present study, the selective blockade of the COX-1 led to a decrease in SC amplitude and tone in the corpus pointing to an excitatory net effect of the COX-1 products.…”

Morphometric-stereological and functional epididymal alterations and a decrease in fertility in rats treated with finasteride and after a 30-day post-treatment recovery period

“…The reduction in serum DHT levels and consequent decrease of this hormone in the intraepididymal compartment in the finasteride group could explain the epididymal structural alterations and the decrease in sperm transit time, despite the unaltered daily sperm production in any of the groups studied. Local factors such as endothelin-1 (50), cGMP, androgens (51,52), and prostaglandins (53) can affect peristalsis in the epididymal duct by modulating the activity of epididymal muscle.…”

Differential modulation of bovine epididymal activity by oxytocin and noradrenaline

“…Several local factors like endothelin-1 (Peri et al 1998), cyclic GMP (Mewe et al 2006b) and prostaglandins (Cosentino et al 1984, Mewe et al 2006a appear to be involved in the modulation of epididymal phasic activity. It is also well established that oxytocin (OT) is implicated in many male reproductive functions including steroidogenesis and reproductive tract contractility , Thackare et al 2006.…”