Related Experiment Video
Updated: Aug 11, 2026

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology
Published on: August 18, 2014
The paradox of smooth muscle physiology
1Institute for Molecular Medicine and Genetics, Medical College of Georgia, 1120 15th Street, Augusta, GA, USA.
Abstract:
Vascular smooth muscle tone is controlled by a balance between the cellular signaling pathways that mediate the generation of force (contraction) and the release of force (relaxation). The signaling events that activate contraction include Ca(2+)-dependent myosin light chain phosphorylation. The signaling events that mediate relaxation include the removal of a contractile agonist (passive relaxation) and activation of cyclic nucleotide-dependent signaling pathways in the continued presence of a contractile agonist (active relaxation). The major questions that remain in contractile physiology include (1) how is tonic force maintained when intracellular Ca(2+) levels and myosin light chain phosphorylation have returned to basal levels; and (2) what is the mechanism of cyclic nucleotide-dependent relaxation? This review focuses on these specific controversies surrounding the molecular mechanisms of contraction and relaxation of vascular smooth muscle.
More Related Videos
Related Concept Videos
Overview of Muscle Tissues
Elasticity
Elasticity is the ability of muscles to stretch and return to their original shape. This property is partly due to elastic fibers — macromolecules that run through the muscles. These fibers are firm and resilient,...
Structure and Organization of Smooth Muscles
Structure of smooth muscle cell
Smooth muscle cells are spindle-shaped with tapering ends and a...
Functions of Smooth Muscles
Function of visceral smooth muscles
Visceral smooth muscle is found in the walls of all hollow organs, except the heart, and is a key player in the involuntary movements that drive the functioning of these internal organs. This tissue is arranged in...
Fascicle Arrangement in Skeletal Muscles
The four primary types of muscle based on fascicle arrangement are:
Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
Autoregulation of Blood Flow
Chemical Signaling in Autoregulation
Chemical signaling operates at the precapillary sphincter level, inciting either contraction or relaxation.

