  Spatiotemporal patterns are common in biological systems. For
electrically-coupled cells previous studies of pattern formation have mainly
used external forcing as the main bifurcation parameter. The purpose of this
paper is to show that spatiotemporal patterns in electrically-coupled smooth
muscle cells occur even in the absence of forcing. We study a
reaction-diffusion system with the Morris-Lecar equations and observe a wide
range of spatiotemporal patterns for different values of the model parameters.
Some aspects of these patterns are explained via a bifurcation analysis of the
system without coupling -- in particular Type I and Type II excitability both
occur. We show the patterns are not due to a Turing instability and use
travelling wave coordinates to analyse travelling waves.
