Intra-and intercellular calcium waves in cultured human myometrium.

Intracellular calcium waves were observed in cultured human myometrium using confocal laser scanning microscopy in the epifluorescence mode. Intracellular calcium waves were observed following stimulation of the cells with 10 mU ml-1 oxytocin in physiological bathing solution, or following substitution of tetraethylammonium chloride for NaCl. Intracellular wave speeds were 18.9 +/- 8.2 microns s-1 in physiological bathing solution. Intracellular calcium waves were also observed in cells bathed in calcium-free solutions, with no significant differences in wave speeds. Calcium waves that crossed cell boundaries were also observed. Some intercellular calcium waves travelled large distances (> 500 microns). Wave speeds for intercellular waves were 7.8 +/- 1.6 microns s-1. Attempts to use octanol to determine the contribution of gap junctions to intercellular calcium wave propagation were unsuccessful because of direct effects of 2 mM octanol on calcium oscillations. These data demonstrate that intra- and intercellular calcium waves are a means of tissue level communication in myometrium that is distinct from action potentials with regard to mechanisms of action, propagation speeds, responses to stimuli, and responses to inhibitors.