Figure 8. Smooth muscle cell disruption has no effect on conduction.

Simulations: endothelial cells within one arterial segment (red band denoted by arrowhead) were voltage clamped 15 mV negative to resting V_m (−40 mV) for 250 ms (A and B) or 5000 ms (C). Electrical and vasomotor responses were monitored every 500 μm from site of endothelial cell stimulation under resting conditions and following the disruption of muscle cell communication in 4 consecutive arterial segments along the conduction pathway (denoted by the rectangle). A and B, the predicted electrical response of endothelial and smooth muscle cells as colour-mapped along the vessel wall and presented in 2-D voltage plots (at 250 ms), respectively. C, the predicted vasodilator response (at 5000 ms) prior to and following smooth muscle cell disruption. D and E, experimental observations (Emerson & Segal, 2000a): endothelial cells within a small region of a retractor muscle feed artery were stimulated with acetylcholine and responses monitored close to or remote from the site of stimulation. Membrane potential and vasomotor responses were recorded prior to and following the use of light dye treatment to disrupt smooth muscle cell communication within the region of the feed artery denoted by rectangle.