The objectives in this special issue are (1) to critically review current information on the mechanisms coupling extracellular regulatory signals to regulation of cross-bridge cycling and proliferation in smooth muscle, and (2) identify significant gaps or unresolved issues that are important topics for future research. The experimental and analytical difficulties discussed above are increasingly recognized and surmounted. Elucidation of the molecular and cellular events underlying the biologal properties of smooth muscle is in the midst of a period of rapid progress. While the reviews reveal many gaps to be filled and illustrate areas of contention, they also capture the excitement of new discoveries.

Signal transduction and regulation in smooth muscle: Problems and progress

Applicability of the sliding filament/crossbridge paradigm to smooth muscle
Regulation of cross-bridge cycling by Ca2+ in smooth muscle
Calcium permeant ion channels in smooth muscle
Pharmacomechanical coupling: the role of calcium, G-proteins, kinases and phosphatases
Molecular and cellular phenotypes and their regulation in smooth muscle.