Functional Role of Pacemaking Cells in the Female Reproductive Tract in Health and Disease

Abstract

Oviducts are lined by smooth muscle which displays rhythmic electrical pacemaker activity that is coupled to mechanical contractions. These contractions, along with cilia beating and epithelial secretions aid the propulsion of the ova to the site of fertilization. Following fertilization, smooth muscle contractions and epithelial secretions are thought to be responsible for the transport of the zygote to the uterus. The contractile activity of oviductal smooth muscle is therefore vital for normal fertility however, it is not understood how these contractions direct ova movement. Aims: (i) examine the cellular mechanisms underlying oviduct smooth muscle excitability; (ii) evaluate whether specialized interstitial cells of Cajal (ICC)‐like cells are responsible for oviduct excitability and (iii) determine the disruption in pacemaker function during inflammation. Results: ICC are responsible for generating pacemaker activity that underlies contractile activity of the oviduct. ICC are disrupted and pacemaker activity damaged by inflammation of the reproductive tract, leading to loss of spontaneous smooth muscle contractions, thus providing an explanation why inflammation can cause tubal infertility. Conclusions: The findings reveal the origin of spontaneous contractions in the oviduct that is necessary for egg and embryonic transport. Grant support was obtained from NIH DK57236 and PHS AI49354.