Localized Ca2+ uncaging induces Ca2+ release through IP3R in smooth muscle.

Publisher: Nature Publishing Group Country of Publication: United States NLM ID: 100956087 Publication Model: Print Cited Medium: Print ISSN: 1671-4083 (Print) Linking ISSN: 16714083 NLM ISO Abbreviation: Acta Pharmacol Sin Subsets: MEDLINE

Publication: 2009- : New York : Nature Publishing Group
Original Publication: Beijing, China : Science Press, c2000-

Calcium/*metabolism ; Calcium Signaling/*physiology ; Inositol 1,4,5-Trisphosphate Receptors/*metabolism ; Myocytes, Smooth Muscle/*metabolism ; Urinary Bladder/*metabolism; Animals ; Macrocyclic Compounds/pharmacology ; Mice ; Oxazoles/pharmacology ; Photolysis ; Ryanodine/pharmacology ; Ryanodine Receptor Calcium Release Channel/metabolism ; Sarcoplasmic Reticulum/metabolism ; Ultraviolet Rays

Aim: Our previous study indicated that there are two types of Ca2+ release events seen in intact mouse bladder tissue. In this study our aim is to investigate the mechanism that underlies the phenomena of Ca2+ release in smooth muscle.
Methods: Single cells were isolated and tissue segments were prepared by cutting the detrusor into 0.1 cm x 0.5 cm strips running along the axis from the neck to the fundus. Single cells and intact tissue strips were co-loaded with the Ca2+ indicator and caged Ca2+ by incubation with 10 micromol/L Fluo-4 AM and DMNP-EDTA-AM. Fluo-4 AM fluorescence was detected by laser scanning confocal microscopy, and local uncaging of DMNP-EGTA was achieved by brief exposure to the output of a diode-pumped, Ti:sapphire laser tuned to 730 nm.
Results: Local uncaging of caged Ca2+ was able to trigger Ca2+ release events in both single cells and tissue strips from mouse bladder. The Ca2+ release events could not be blocked by ryanodine alone, but the property of the Ca2+ release was markedly altered. Surprisingly, in the presence of ryanodine, Xestospongin C completely inhibited the Ca2+ release events both in single cell and tissue experiments.
Conclusion: (1) Two photon flash photolysis (TPFP) triggers Ca2+ induced Ca2+ release. This process involves release through type 2 ryanodine receptor channels; (2) TPFP results in the release of Ca2+ through inositol 1,4,5-trisphosphate receptors in the absence of phospholipase C activation.

0 (Inositol 1,4,5-Trisphosphate Receptors)
0 (Macrocyclic Compounds)
0 (Oxazoles)
0 (Ryanodine Receptor Calcium Release Channel)
0 (xestospongin C)
15662-33-6 (Ryanodine)
SY7Q814VUP (Calcium)

Date Created: 20060622 Date Completed: 20070807 Latest Revision: 20131121

20250114

10.1111/j.1745-7254.2006.00389.x

16787580