Figure 1. Purinergic neuroeffector Ca²⁺ transients (NCTs).

A small region close to the surface of the mouse vas deferens is shown during field stimulation (#) at 1 Hz (while recording images at 2 frames s⁻¹). Smooth muscle cells are heterogeneously loaded with the Ca²⁺ indicator Oregon-BAPTA. A, a set of selected frames to demonstrate that NCTs (arrows) are intermittently evoked at several sites within smooth muscle cells. The time at which the image was acquired is marked on each frame. B, another selection of images, from the same recording, showing all NCTs arising at a given site. Each frame should be compared with the control frame (A, frame 1). B, frame 5, shows synchronous events at two sites within the same smooth muscle cell.