Mesh : Animals Cell Membrane / drug effects metabolism Cell Membrane Permeability / drug effects Cells, Cultured Female Flow Cytometry Hydrogen Peroxide / pharmacology Ionophores / pharmacology Membrane Potentials / drug effects Myometrium / cytology drug effects metabolism Nitric Oxide Donors / pharmacology Nitrogen Oxides / pharmacology Nitroprusside / pharmacology Potassium / metabolism Sarcolemma / drug effects metabolism Swine Valinomycin / pharmacology