Petra Turkewitsch | McGill University and Cegep de la Gaspésie (original) (raw)
Papers by Petra Turkewitsch
Polymer, 2002
Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯... more Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯uorosensor were prepared against adenosine 3 0 ,5 0 -cyclic monophosphate (cAMP). The time-resolved¯uorescence decay analysis was used to investigate the speci®city and af®nity of the binding of template molecules to the MIP. The¯uorescence decays were modelled in terms of lifetime distributions and twō uorescence lifetimes were observed for the MIPs. The lifetime distributions are interpreted in terms of the heterogeneity of the functionalised imprinted cavities. Quenching of¯uorescence of the imprinted polymer with increasing concentration of aqueous cAMP was observed from the¯uorescence lifetime parameters data. The mechanisms of interactions between the cAMP and¯uorosensor molecules inside the imprinted cavity in comparison with the interactions in solution are discussed. q
Chemical Physics Letters, 1996
Addition of the cyclic nucleotides cAMP and cGMP to aqueous solutions of trans-4-(p-N,N-dimethyla... more Addition of the cyclic nucleotides cAMP and cGMP to aqueous solutions of trans-4-(p-N,N-dimethylaminostyryl)-Nvinylbenzylpyridinium chloride (1) dramatically enhanced the fluorescence quantum yield of 1 with concomitant slight red shifts of the Am~ ,, and had slight hyperchromic and bathochromic effects on the absorbance of 1. In contrast, D-ribose-5phosphate had no such effects. These results suggest that 1 preferentially associates with nucleotides in aqueous solution, with equilibrium constants for cAMP and cGMP of 212 _+ 46 and 285 + 18 M-i, respectively. Thus, dye 1 may serve as a starting point for the development of more sensitive and specific probes for cyclic nucleotides.
Journal of The Chemical Society, Faraday Transactions, 1995
Journal of The Chemical Society, Faraday Transactions, 1998
The Ñuorescence quantum yields of two cationic styrylpyridinium dyes, trans-4-(p-N,N-dimethylamin... more The Ñuorescence quantum yields of two cationic styrylpyridinium dyes, trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (1) and trans-4-(p-N,N-dimethylaminostyryl)-N-phenethylpyridinium bromide (2), increase dramatically in the presence of low concentrations of DNA with slight blue shifts (4 and 8 nm, respectively) of the emission maxima. These spectral changes suggest that the dyes are interacting with double helical DNA. Dyes 1 and 2 display similar enhancements in Ñuorescence in the presence of proteins, such as bovine serum albumin, with blue shifts in the emission maxima of 28 and 33 nm, respectively, suggesting that they also interact with proteins. Equilibrium association constants in the order of 104 l mol~1 were determined for the binding of 1 and 2 to bovine serum albumin. This family of dyes may be useful for the Ñuorescence detection of very low concentrations of DNA and proteins, and for the Ñuorescence staining of DNA and proteins in electrophoresis gels.
Analytical Chemistry, 1998
ABSTRACT
Journal of Photochemistry and Photobiology A-chemistry, 1998
The newly synthesized trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (1) di... more The newly synthesized trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (1) displays strong solvatochromic behavior resulting from a large increase of ∼18 D in its dipole moment upon excitation. This indicates that its excited state has considerable charge transfer character, suggesting that it may be subject to solute-induced fluorescence changes. The fluorescence quantum yield of 1 is enhanced dramatically (12-fold) in the presence of a
Analytical Chemistry, 1998
ABSTRACT
![Research paper thumbnail of Substituted 4-[4-(dimethylamino)styryl]pyridinium salt as a fluorescent probe for cell microviscosity](https://attachments.academia-assets.com/49228982/thumbnails/1.jpg)
](Biosensors & Bioelectronics, 2003
In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluor... more In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluorescence, in which excitation at either 469 or 360 nm produced an emission band near 600 nm. Increasing the viscosity of the environment intensified the fluorescence emission obtained at the longer wavelength of excitation, whereas the emission at the lower wavelength of excitation showed little change in intensity. Thus, using the ratio of the 600 nm emission obtained by exciting at 469 nm to that obtained with 360 nm excitation, it is possible to obtain a value related to the local viscosity that does not depend on the system parameters. The fluorescence emission of the dye in aqueous solution, as well as in living cells, is well suited for use with visible fluorescence spectroscopy. The N -carboxymethyl butyl ester DMASP derivative (1) was found to be irreversibly loaded into living smooth muscle cells, presumably because it is hydrolyzed by cellular esterases, transforming it into a membrane-impermeable fluorescent carboxylate DMASP derivative. (2) After calibrating 2 against glycerol/water and sucrose/water mixtures of known viscosity, the fluorescence ratio generated from cultured smooth muscle cells in dual-excitation mode gave an average intracellular viscosity of 4.5 cP. This value corresponds to those reported in the literature. #
![Research paper thumbnail of Substituted 4-[4-(dimethylamino)styryl]pyridinium salt as a fluorescent probe for cell microviscosity](https://attachments.academia-assets.com/50665267/thumbnails/1.jpg)
](Biosensors and Bioelectronics, 2003
In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluor... more In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluorescence, in which excitation at either 469 or 360 nm produced an emission band near 600 nm. Increasing the viscosity of the environment intensified the fluorescence emission obtained at the longer wavelength of excitation, whereas the emission at the lower wavelength of excitation showed little change in intensity. Thus, using the ratio of the 600 nm emission obtained by exciting at 469 nm to that obtained with 360 nm excitation, it is possible to obtain a value related to the local viscosity that does not depend on the system parameters. The fluorescence emission of the dye in aqueous solution, as well as in living cells, is well suited for use with visible fluorescence spectroscopy. The N -carboxymethyl butyl ester DMASP derivative (1) was found to be irreversibly loaded into living smooth muscle cells, presumably because it is hydrolyzed by cellular esterases, transforming it into a membrane-impermeable fluorescent carboxylate DMASP derivative. (2) After calibrating 2 against glycerol/water and sucrose/water mixtures of known viscosity, the fluorescence ratio generated from cultured smooth muscle cells in dual-excitation mode gave an average intracellular viscosity of 4.5 cP. This value corresponds to those reported in the literature. #
Analytical Chemistry, 1998
ABSTRACT
Journal of Luminescence, 2003
Molecular imprinting of synthetic polymers provides a powerful approach to control electronic and... more Molecular imprinting of synthetic polymers provides a powerful approach to control electronic and optical properties through nanoscale modification of molecular design of the material. The functional monomers were co-polymerised in the presence of a target/imprint molecule, which acts as a molecular template. Subsequent removal of the template molecules left behind functionalised cavities that are able to recognise the template molecule.
Journal of the Chemical Society, Faraday Transactions, 1995
Analytica Chimica Acta, 2009
Polymer, 2002
Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯... more Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯uorosensor were prepared against adenosine 3 0 ,5 0 -cyclic monophosphate (cAMP). The time-resolved¯uorescence decay analysis was used to investigate the speci®city and af®nity of the binding of template molecules to the MIP. The¯uorescence decays were modelled in terms of lifetime distributions and twō uorescence lifetimes were observed for the MIPs. The lifetime distributions are interpreted in terms of the heterogeneity of the functionalised imprinted cavities. Quenching of¯uorescence of the imprinted polymer with increasing concentration of aqueous cAMP was observed from the¯uorescence lifetime parameters data. The mechanisms of interactions between the cAMP and¯uorosensor molecules inside the imprinted cavity in comparison with the interactions in solution are discussed. q
We tested the hypothesis that in airway smooth muscle cells stimulation of G-protein-coupled rece... more We tested the hypothesis that in airway smooth muscle cells stimulation of G-protein-coupled receptors (GPCRs) by contractile agonists activates Src kinase and that this kinase modulates cell contractility and calcium (Ca 2+ ) signalling by affecting the levels of phospholipase C (PLC) substrate, phosphatidylinositol 4,5bisphosphate (PIP2). Stimulation of cultured rat tracheal smooth muscle cells with serotonin (5-HT) induced an increase in Src activity, Ca 2+ mobilisation and contraction (decrease in cell area). 5-HT-evoked cell contraction was reduced by a specific inhibitor of Src family kinases, 4-amino-5(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4d]pyrimidine (PP1). Peak Ca 2+ responses to 5-HT were attenuated by PP1 as well as an anti-Src blocking antibody and augmented by expression of constitutively activated, Y529F Src. Sustained phase of Ca 2+ responses to 5-HT as well as Ca 2+ influx resulting from emptying of Ca 2+ stores in the endoplasmic reticulum by thapsigargin were also decreased after PP1 treatment. PP1 significantly reduced the turnover of inositol phosphates (IPs) produced upon 5-HT stimulation and the amount of PIP2 in the Triton X-100-insoluble lipid fraction. Overall, these data demonstrate that in rat tracheal smooth muscle cells Src kinase modulates 5-HTevoked cell contractility and Ca 2+ signalling by regulating PIP2 levels and Ca 2+ influx.
![Research paper thumbnail of LY-294002 [2-(4-Morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] Affects Calcium Signaling in Airway Smooth Muscle Cells Independently of Phosphoinositide 3-Kinase Inhibition](https://attachments.academia-assets.com/49271228/thumbnails/1.jpg)
](Journal of Pharmacology and Experimental Therapeutics, 2004
Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration... more Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration by several mechanisms. We have investigated the effects of phosphoinositide 3-kinase (PI3K) inhibitors wortmannin and LY-294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] on Ca 2ϩ signaling in rat airway smooth muscle (ASM) cells using fura-2 and imaging methodology. Wortmannin (1 M) and LY-294002 (1 and 10 M) had opposite effects: wortmannin caused a small increase, whereas LY-294002 caused a significant decrease of peak Ca 2ϩ responses to serotonin (5-HT). LY-294002 (10 M) diminished 5-HT-induced ASM cell contraction, measured as a change in cell surface area, and inositol phosphate formation, measured by anion exchange chromatography. Thin layer chromatogra-This study was funded by Canadian Institutes of Health Grant MOP-36334. Article, publication date, and citation information can be found at
American Journal of Physiology - Lung Cellular and Molecular Physiology, 2002
We tested the hypothesis that, in airway smooth muscle cells, stimulation of G-protein-coupled re... more We tested the hypothesis that, in airway smooth muscle cells, stimulation of G-protein-coupled receptors by contractile agonists activates Src kinase and that this kinase modulates cell contractility and Ca(2+) signaling by affecting the levels of the phospholipase C substrate phosphatidylinositol 4,5-bisphosphate (PIP(2)). Stimulation of cultured rat tracheal smooth muscle cells with serotonin (5-HT) induced an increase in Src activity, Ca(2+) mobilization, and contraction (decrease in cell area). 5-HT-evoked cell contraction was reduced by a specific inhibitor of Src family kinases, 4-amino-5(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1). Peak Ca(2+) responses to 5-HT were attenuated by PP1 and an anti-Src-blocking antibody and augmented by expression of constitutively activated Y529F Src. Sustained phases of Ca(2+) responses to 5-HT and Ca(2+) influx resulting from emptying of Ca(2+) stores in the endoplasmic reticulum by thapsigargin were also decreased after PP1 treatment. PP1 significantly reduced the turnover of inositol phosphates produced on 5-HT stimulation and the amount of PIP(2) in the Triton X-100-insoluble lipid fraction. Overall, these data demonstrate that, in rat tracheal smooth muscle cells, Src kinase modulates 5-HT-evoked cell contractility and Ca(2+) signaling by regulating PIP(2) levels and Ca(2+) influx.
![Research paper thumbnail of LY-294002 [2-(4-Morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] Affects Calcium Signaling in Airway Smooth Muscle Cells Independently of Phosphoinositide 3-Kinase Inhibition](https://attachments.academia-assets.com/48963984/thumbnails/1.jpg)
](Journal of Pharmacology and Experimental Therapeutics, 2004
Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration... more Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration by several mechanisms. We have investigated the effects of phosphoinositide 3-kinase (PI3K) inhibitors wortmannin and LY-294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] on Ca 2ϩ signaling in rat airway smooth muscle (ASM) cells using fura-2 and imaging methodology. Wortmannin (1 M) and LY-294002 (1 and 10 M) had opposite effects: wortmannin caused a small increase, whereas LY-294002 caused a significant decrease of peak Ca 2ϩ responses to serotonin (5-HT). LY-294002 (10 M) diminished 5-HT-induced ASM cell contraction, measured as a change in cell surface area, and inositol phosphate formation, measured by anion exchange chromatography. Thin layer chromatogra-This study was funded by Canadian Institutes of Health Grant MOP-36334. Article, publication date, and citation information can be found at
You might find this additional information useful...
Polymer, 2002
Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯... more Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯uorosensor were prepared against adenosine 3 0 ,5 0 -cyclic monophosphate (cAMP). The time-resolved¯uorescence decay analysis was used to investigate the speci®city and af®nity of the binding of template molecules to the MIP. The¯uorescence decays were modelled in terms of lifetime distributions and twō uorescence lifetimes were observed for the MIPs. The lifetime distributions are interpreted in terms of the heterogeneity of the functionalised imprinted cavities. Quenching of¯uorescence of the imprinted polymer with increasing concentration of aqueous cAMP was observed from the¯uorescence lifetime parameters data. The mechanisms of interactions between the cAMP and¯uorosensor molecules inside the imprinted cavity in comparison with the interactions in solution are discussed. q
Chemical Physics Letters, 1996
Addition of the cyclic nucleotides cAMP and cGMP to aqueous solutions of trans-4-(p-N,N-dimethyla... more Addition of the cyclic nucleotides cAMP and cGMP to aqueous solutions of trans-4-(p-N,N-dimethylaminostyryl)-Nvinylbenzylpyridinium chloride (1) dramatically enhanced the fluorescence quantum yield of 1 with concomitant slight red shifts of the Am~ ,, and had slight hyperchromic and bathochromic effects on the absorbance of 1. In contrast, D-ribose-5phosphate had no such effects. These results suggest that 1 preferentially associates with nucleotides in aqueous solution, with equilibrium constants for cAMP and cGMP of 212 _+ 46 and 285 + 18 M-i, respectively. Thus, dye 1 may serve as a starting point for the development of more sensitive and specific probes for cyclic nucleotides.
Journal of The Chemical Society, Faraday Transactions, 1995
Journal of The Chemical Society, Faraday Transactions, 1998
The Ñuorescence quantum yields of two cationic styrylpyridinium dyes, trans-4-(p-N,N-dimethylamin... more The Ñuorescence quantum yields of two cationic styrylpyridinium dyes, trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (1) and trans-4-(p-N,N-dimethylaminostyryl)-N-phenethylpyridinium bromide (2), increase dramatically in the presence of low concentrations of DNA with slight blue shifts (4 and 8 nm, respectively) of the emission maxima. These spectral changes suggest that the dyes are interacting with double helical DNA. Dyes 1 and 2 display similar enhancements in Ñuorescence in the presence of proteins, such as bovine serum albumin, with blue shifts in the emission maxima of 28 and 33 nm, respectively, suggesting that they also interact with proteins. Equilibrium association constants in the order of 104 l mol~1 were determined for the binding of 1 and 2 to bovine serum albumin. This family of dyes may be useful for the Ñuorescence detection of very low concentrations of DNA and proteins, and for the Ñuorescence staining of DNA and proteins in electrophoresis gels.
Analytical Chemistry, 1998
ABSTRACT
Journal of Photochemistry and Photobiology A-chemistry, 1998
The newly synthesized trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (1) di... more The newly synthesized trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (1) displays strong solvatochromic behavior resulting from a large increase of ∼18 D in its dipole moment upon excitation. This indicates that its excited state has considerable charge transfer character, suggesting that it may be subject to solute-induced fluorescence changes. The fluorescence quantum yield of 1 is enhanced dramatically (12-fold) in the presence of a
Analytical Chemistry, 1998
ABSTRACT
Biosensors & Bioelectronics, 2003
In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluor... more In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluorescence, in which excitation at either 469 or 360 nm produced an emission band near 600 nm. Increasing the viscosity of the environment intensified the fluorescence emission obtained at the longer wavelength of excitation, whereas the emission at the lower wavelength of excitation showed little change in intensity. Thus, using the ratio of the 600 nm emission obtained by exciting at 469 nm to that obtained with 360 nm excitation, it is possible to obtain a value related to the local viscosity that does not depend on the system parameters. The fluorescence emission of the dye in aqueous solution, as well as in living cells, is well suited for use with visible fluorescence spectroscopy. The N -carboxymethyl butyl ester DMASP derivative (1) was found to be irreversibly loaded into living smooth muscle cells, presumably because it is hydrolyzed by cellular esterases, transforming it into a membrane-impermeable fluorescent carboxylate DMASP derivative. (2) After calibrating 2 against glycerol/water and sucrose/water mixtures of known viscosity, the fluorescence ratio generated from cultured smooth muscle cells in dual-excitation mode gave an average intracellular viscosity of 4.5 cP. This value corresponds to those reported in the literature. #
Biosensors and Bioelectronics, 2003
In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluor... more In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluorescence, in which excitation at either 469 or 360 nm produced an emission band near 600 nm. Increasing the viscosity of the environment intensified the fluorescence emission obtained at the longer wavelength of excitation, whereas the emission at the lower wavelength of excitation showed little change in intensity. Thus, using the ratio of the 600 nm emission obtained by exciting at 469 nm to that obtained with 360 nm excitation, it is possible to obtain a value related to the local viscosity that does not depend on the system parameters. The fluorescence emission of the dye in aqueous solution, as well as in living cells, is well suited for use with visible fluorescence spectroscopy. The N -carboxymethyl butyl ester DMASP derivative (1) was found to be irreversibly loaded into living smooth muscle cells, presumably because it is hydrolyzed by cellular esterases, transforming it into a membrane-impermeable fluorescent carboxylate DMASP derivative. (2) After calibrating 2 against glycerol/water and sucrose/water mixtures of known viscosity, the fluorescence ratio generated from cultured smooth muscle cells in dual-excitation mode gave an average intracellular viscosity of 4.5 cP. This value corresponds to those reported in the literature. #
Analytical Chemistry, 1998
ABSTRACT
Journal of Luminescence, 2003
Molecular imprinting of synthetic polymers provides a powerful approach to control electronic and... more Molecular imprinting of synthetic polymers provides a powerful approach to control electronic and optical properties through nanoscale modification of molecular design of the material. The functional monomers were co-polymerised in the presence of a target/imprint molecule, which acts as a molecular template. Subsequent removal of the template molecules left behind functionalised cavities that are able to recognise the template molecule.
Journal of the Chemical Society, Faraday Transactions, 1995
Analytica Chimica Acta, 2009
Polymer, 2002
Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯... more Molecularly imprinted polymers (MIPs) with template-selective recognition sites and incorporated¯uorosensor were prepared against adenosine 3 0 ,5 0 -cyclic monophosphate (cAMP). The time-resolved¯uorescence decay analysis was used to investigate the speci®city and af®nity of the binding of template molecules to the MIP. The¯uorescence decays were modelled in terms of lifetime distributions and twō uorescence lifetimes were observed for the MIPs. The lifetime distributions are interpreted in terms of the heterogeneity of the functionalised imprinted cavities. Quenching of¯uorescence of the imprinted polymer with increasing concentration of aqueous cAMP was observed from the¯uorescence lifetime parameters data. The mechanisms of interactions between the cAMP and¯uorosensor molecules inside the imprinted cavity in comparison with the interactions in solution are discussed. q
We tested the hypothesis that in airway smooth muscle cells stimulation of G-protein-coupled rece... more We tested the hypothesis that in airway smooth muscle cells stimulation of G-protein-coupled receptors (GPCRs) by contractile agonists activates Src kinase and that this kinase modulates cell contractility and calcium (Ca 2+ ) signalling by affecting the levels of phospholipase C (PLC) substrate, phosphatidylinositol 4,5bisphosphate (PIP2). Stimulation of cultured rat tracheal smooth muscle cells with serotonin (5-HT) induced an increase in Src activity, Ca 2+ mobilisation and contraction (decrease in cell area). 5-HT-evoked cell contraction was reduced by a specific inhibitor of Src family kinases, 4-amino-5(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4d]pyrimidine (PP1). Peak Ca 2+ responses to 5-HT were attenuated by PP1 as well as an anti-Src blocking antibody and augmented by expression of constitutively activated, Y529F Src. Sustained phase of Ca 2+ responses to 5-HT as well as Ca 2+ influx resulting from emptying of Ca 2+ stores in the endoplasmic reticulum by thapsigargin were also decreased after PP1 treatment. PP1 significantly reduced the turnover of inositol phosphates (IPs) produced upon 5-HT stimulation and the amount of PIP2 in the Triton X-100-insoluble lipid fraction. Overall, these data demonstrate that in rat tracheal smooth muscle cells Src kinase modulates 5-HTevoked cell contractility and Ca 2+ signalling by regulating PIP2 levels and Ca 2+ influx.
Journal of Pharmacology and Experimental Therapeutics, 2004
Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration... more Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration by several mechanisms. We have investigated the effects of phosphoinositide 3-kinase (PI3K) inhibitors wortmannin and LY-294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] on Ca 2ϩ signaling in rat airway smooth muscle (ASM) cells using fura-2 and imaging methodology. Wortmannin (1 M) and LY-294002 (1 and 10 M) had opposite effects: wortmannin caused a small increase, whereas LY-294002 caused a significant decrease of peak Ca 2ϩ responses to serotonin (5-HT). LY-294002 (10 M) diminished 5-HT-induced ASM cell contraction, measured as a change in cell surface area, and inositol phosphate formation, measured by anion exchange chromatography. Thin layer chromatogra-This study was funded by Canadian Institutes of Health Grant MOP-36334. Article, publication date, and citation information can be found at
American Journal of Physiology - Lung Cellular and Molecular Physiology, 2002
We tested the hypothesis that, in airway smooth muscle cells, stimulation of G-protein-coupled re... more We tested the hypothesis that, in airway smooth muscle cells, stimulation of G-protein-coupled receptors by contractile agonists activates Src kinase and that this kinase modulates cell contractility and Ca(2+) signaling by affecting the levels of the phospholipase C substrate phosphatidylinositol 4,5-bisphosphate (PIP(2)). Stimulation of cultured rat tracheal smooth muscle cells with serotonin (5-HT) induced an increase in Src activity, Ca(2+) mobilization, and contraction (decrease in cell area). 5-HT-evoked cell contraction was reduced by a specific inhibitor of Src family kinases, 4-amino-5(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1). Peak Ca(2+) responses to 5-HT were attenuated by PP1 and an anti-Src-blocking antibody and augmented by expression of constitutively activated Y529F Src. Sustained phases of Ca(2+) responses to 5-HT and Ca(2+) influx resulting from emptying of Ca(2+) stores in the endoplasmic reticulum by thapsigargin were also decreased after PP1 treatment. PP1 significantly reduced the turnover of inositol phosphates produced on 5-HT stimulation and the amount of PIP(2) in the Triton X-100-insoluble lipid fraction. Overall, these data demonstrate that, in rat tracheal smooth muscle cells, Src kinase modulates 5-HT-evoked cell contractility and Ca(2+) signaling by regulating PIP(2) levels and Ca(2+) influx.
Journal of Pharmacology and Experimental Therapeutics, 2004
Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration... more Phosphoinositide 3-kinase (PI3K) may potentially influence intracellular [Ca 2ϩ ] i concentration by several mechanisms. We have investigated the effects of phosphoinositide 3-kinase (PI3K) inhibitors wortmannin and LY-294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] on Ca 2ϩ signaling in rat airway smooth muscle (ASM) cells using fura-2 and imaging methodology. Wortmannin (1 M) and LY-294002 (1 and 10 M) had opposite effects: wortmannin caused a small increase, whereas LY-294002 caused a significant decrease of peak Ca 2ϩ responses to serotonin (5-HT). LY-294002 (10 M) diminished 5-HT-induced ASM cell contraction, measured as a change in cell surface area, and inositol phosphate formation, measured by anion exchange chromatography. Thin layer chromatogra-This study was funded by Canadian Institutes of Health Grant MOP-36334. Article, publication date, and citation information can be found at
You might find this additional information useful...