Abstract: 12

PACEMAKER CELLS OF THE UTERUS.

Saryu Goel^{1 *}, Neeta Goel¹ , Rita Loch-Caruso^{1 *}
Department of Environmental and Industrial Health, University of Michigan, Ann Arbor, MI. ¹

Uterine muscle contractions are central to the transportation of an ovum from the ovary to the oviduct, transportation of an embryo to the uterus, and the delivery of a fetus at term. It has been suggested that all uterine smooth muscle cells have the capacity to act as pacemaker cells, and thereby initiate contractions. In a previous study, we observed that <1% of the isolated myometrial cells generated spontaneous calcium oscillations. We hypothesized that only selected myometrial cells have the potential to act as pacemaker cells. Because selective staining with methylene blue is a characteristic of the pacemaker cells of the gastrointestinal tract (interstitial cells of Cajal), uterine tissues and isolated myometrial cells in culture were incubated with 50 µM methylene blue in Krebs solution. Some cells in the longitudinal smooth muscle layer of the fallopian tubes and uterus stained deep blue on exposure to methylene blue. These cells were long and spindle-shaped. The methylene blue-stained myometrial cells in culture were small with granular cytoplasm. The cells demonstrating calcium oscillations in our previous study had similar morphological features. Antibody to the c-kit receptor tyrosine kinase present in the membrane of interstitial cells of Cajal has been shown to inhibit the electrical activity in these cells. In the present study, spontaneous contractions in uterine muscle strips were measured using standard muscle baths. Treatment of uterine strips with anti-c-kit antibody resulted in irregular contractions. Immunohistochemical staining of myometrial cells with anti-c-kit antibody and horseradish peroxidase-conjugated antibody also resulted in positive deposits. These data indicate that the uterus may have specialized cells that are pacemakers, and that these cells may be differentiated from non-pacemaker cells based on the above mentioned features.

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.