Ca2+ Regulation in Detrusor Smooth Muscle From Ovine Fetal Bladder After In Utero Bladder Outflow Obstruction

Purpose: We characterized intracellular Ca2+ regulation in fetal bladders following outflow obstruction by examining the Ca2+ response to agonists in smooth muscle cells. Materials and Methods: Severe bladder outflow obstruction was induced in male fetal sheep by placing a urethral ring and urachal ligation midway through gestation at 75 days. Fetuses were examined 30 days after surgery. Intracellular Ca2+ in single smooth muscle cells isolated from the bladder wall was measured with epifluorescence microscopy using fura-2(AM) during exposure to agonists, such as carbachol and adenosine triphosphate, and to other activators, such as caffeine and KCl. Results: Detrusor smooth muscle cells from obstructed bladders had resting intracellular Ca2+ similar to that in sham operated controls. The maximal response to carbachol was decreased following obstruction (p