title: Synthesis and two-photon photolysis of 6-(ortho-nitroveratryl)-caged IP3 in living cells.
abstract: The synthesis of a photolabile derivative of inositol-1,4,5-trisphosphate (IP3) is described. This new caged second messenger (6-ortho-nitroveratryl)-IP3 (6-NV-IP3) has an extinction coefficient of 5000 M(-1) cm(-1) at 350 nm, and a quantum yield of photolysis of 0.12. Therefore, 6-NV-IP3 is photolyzed with UV light about three times more efficiently than the widely used P(4(5))-1-(2-nitrophenyl)ethyl-caged IP3 (NPE-IP3). 6-NV-IP3 has a two-photon cross-section of about 0.035 GM at 730 nm. This absorbance is sufficiently large for effective two-photon excitation in living cells at modest power levels. Using near-IR light (5 mW, 710 nm, 80 MHz, pulse-width 70 fs), we produced focal bursts of IP3 in HeLa cells, as revealed by laser-scanning confocal imaging of intracellular Ca2+ concentrations. Therefore, 6-NV-IP3 can be used for efficient, subcellular photorelease of IP3, not only in cultured cells but also, potentially, in vivo. It is in the latter situation that two-photon photolysis should reveal its true forte.
authors.affiliation: Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Kantevari
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Hoang
authors.forename: Jakob
authors.initials: J
authors.lastname: Ogrodnik
authors.forename: Marcel
authors.initials: M
authors.lastname: Egger
authors.forename: Ernst
authors.initials: E
authors.lastname: Niggli
authors.forename: Graham C R
authors.initials: GC
authors.lastname: Ellis-Davies
mesh_terms: D002478:Cells, Cultured; D006367:HeLa Cells; D006801:Humans; D008968:Molecular Conformation; D010777:Photochemistry; D010782:Photolysis; D017785:Photons; D013997:Time Factors