AB277. SPR-04 Myosalpinx contractions are essential for egg/embryo transport in the oviduct

Objective: Oviducts or fallopian tubes are smooth muscle lined dynamic tubular organs that connect the ovaries to the uterus and facilitate several physiological processes including gamete transport, fertilization and early embryo development. Several stages of the reproductive process occur exclusively within the oviduct and are subject to physiological regulation. The four main functions of the oviduct include: (I) the transport of the ovum from the ovary to the site of fertilization; (II) the oviduct aids in transport of spermatozoa from the site of deposition to the site of fertilization within the ampulla; (III) the oviduct provides a suitable environment for the egg with secretions along the duct providing protection of the egg from mechanical damage and for maintenance of viability of the egg during its transport; (IV) transportation of the fertilized ovum (embryo) to the uterus where implantation and further development occurs. Given the complexities and the different physiological functions of the oviduct it is not surprising that it is functionally organized into different regions. Dogma in the literature suggests that egg or embryo transport depends mainly on the incessant beat of the ciliated epithelium towards the uterus. However, egg transport may also be dependent upon contractions of the smooth muscle lined wall or myosalpinx. In order to fully understand the physical mechanisms that contribute to the coordinated movement of the egg we investigated the role of the calcium-activated chloride conductance, Ano1 on the generation of pacemaker activity.

Methods: Video imaging and spatio-temporal mapping along with intracellular microelectrode recordings were performed to define the role of myosalpinx in egg/embryo transport. The Cre-recombinase LoxP technology was also utilized to determine the role of the calcium-activated chloride conductance, Ano1 in adult tissues.

Results: Egg transport is highly dependent upon phasic contractions of the smooth muscle lined wall or myosalpinx. The phasic and propulsive contractions of the myosalpinx depend upon specialized ICC, termed ICC-OVI. There is regional dependence on the role of Ano1 in pacemaker activity and that global reduction in Ano1 in mature female mice leads to reduced fertility.

Conclusions: These data further support the role of myosalpinx activity in egg/embryo transport in the oviduct and the importance of Ano1 in the generation of pacemaker activity within the oviduct. A critical role in Ano1 in egg/embryo transport and fertility is also demonstrated.

Funding Source(s): NIH RO1 DK57236

Keywords: Myosalpinx; oviduct; Ano1; video; electrophysiology