Cultured intestinal smooth muscle cells: its morphology and physiology

The electrical properties and morphological characteristics of cultured smooth muscle cells were studied. During the culture, the cells proliferated, lined up in linear parallel arrays and exhibited a typical formation of hills and valleys. Injection of depolarizing or hyperpolarizing current pulses evoked action potentials in the cells, and the cells often displayed spontaneous action potential activity. These action potentials were found to be calcium dependent. ACh produced membrane depolarization, noradrenaline membrane hyperpolarization. The cells were coupled by low-resistance junctions that permit the cell-to-cell-passage of electrical current and fluorescein dye. The permeability of junction was blocked by the increased concentration of cytoplasmic calcium ions. These results indicate that the cell-to-cell communication properties of cultured smooth muscle cells are modelated by the cytoplasmic calcium ions concentration.