Related Experiment Video
Updated: Sep 6, 2026

Mesenteric Artery Contraction and Relaxation Studies Using Automated Wire Myography
Published on: September 22, 2011
Receptor-operated Ca2(+)-permeable nonselective cation channels in vascular smooth muscle: a physiologic perspective
1Department of Pharmacology and Clinical Pharmacology, St. George's Hospital Medical School, London, United Kingdom. w.large@sghms.ac.uk
Abstract:
This article summarizes the literature on receptor-operated Ca2(+)-permeable nonselective cation channels in vascular smooth muscle cells. One of these conductances, the P2X1 receptor, is a classic ligand-gated channel, but others are likely to be mediated via G-protein-coupled receptors. The most studied receptor-operated channel in vascular myocytes is the norepinephrine-evoked nonselective cation channel in rabbit portal vein myocytes. The data regarding the transduction mechanisms and biophysical properties of whole-cell and single-channel currents in this preparation are described. The channels have a conductance of 20 to 25 pS and complex kinetic behavior with at least two open and two closed states. These channels are activated by norepinephrine and acetylcholine via G-protein-coupled receptors linked to phospholipase C and by diacylglycerol (DAG). The action of DAG occurs by a mechanism independent of protein kinase C, but other kinases may mediate the responses to norepinephrine and DAG. In addition, activation of tyrosine kinases leads to opening of this channel. Other vasoconstrictors, such as endothelin, vasopressin, serotonin, and angiotensin II, open Ca2(+)-permeable nonselective cation channels, but there may be differences between these conductances and the norepinephrine-evoked channels. A homologue of the transient receptor potential protein (TRPC6) is an essential component of the norepinephrine-activated channel in rabbit portal vein, and it is likely that this family of proteins plays an important role in mediating Ca2+ influx in vascular smooth muscle.
More Related Videos
Related Concept Videos
Mechanically-gated Ion Channels
G-Protein Gated Ion Channels
Sensory organs,...
Non-gated Ion Channels
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
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...
Mechanically-gated Ion Channels
Antihypertensive Drugs: Action of Calcium Channel Blockers

