Related Experiment Video
Updated: Aug 7, 2026
17:41
Focal Ca2+ Transient Detection in Smooth Muscle
Published on: June 29, 2009
Localized Ca2+ uncaging induces Ca2+ release through IP3R in smooth muscle
Min Wang1, Zheng Chen, Yan Xing
1Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
Acta Pharmacologica Sinica
|June 22, 2006
Summary
Investigating calcium (Ca2+) release in mouse bladder smooth muscle revealed two distinct mechanisms. Ryanodine and Xestospongin C identified roles for ryanodine and inositol trisphosphate receptors in Ca2+ release.
Area of Science:
- Physiology
- Molecular Biology
- Cell Biology
Background:
- Previous studies identified two types of Ca2+ release events in mouse bladder.
- Understanding the underlying mechanisms of Ca2+ release in smooth muscle is crucial for bladder function.
Purpose of the Study:
- To investigate the mechanisms responsible for Ca2+ release phenomena in mouse bladder smooth muscle cells.
- To elucidate the roles of specific ion channels in regulating intracellular Ca2+ dynamics.
Main Methods:
- Isolated single smooth muscle cells and intact tissue strips from mouse bladder detrusor.
- Co-loading with Ca2+ indicator (Fluo-4 AM) and caged Ca2+ (DMNP-EDTA-AM).
- Laser scanning confocal microscopy and two-photon flash photolysis (TPFP) for localized Ca2+ uncaging.
Main Results:
- TPFP successfully triggered Ca2+ release events in both single cells and tissue strips.
- Ryanodine alone altered, but did not block, Ca2+ release events.
- Xestospongin C, in the presence of ryanodine, completely inhibited Ca2+ release.
Conclusions:
- TPFP induces Ca2+-induced Ca2+ release via type 2 ryanodine receptor channels.
- TPFP also triggers Ca2+ release through inositol 1,4,5-trisphosphate receptors independently of phospholipase C activation.
Related Concept Videos
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:28Nitric Oxide Signaling Pathway
Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:11IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
01:25Smooth Muscle Contraction
Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
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...
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...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...