Platelet-activating factor stimulates protein tyrosine kinase in hamster cheek pouch microcirculation

1995 ◽  
Vol 268 (1) ◽  
pp. H399-H403 ◽  
Author(s):  
D. Kim ◽  
W. N. Duran
Keyword(s):  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Platelet Activating Factor ◽  
Fluorescein Isothiocyanate ◽  
Cheek Pouch ◽  
Computer Assisted ◽  
Hamster Cheek Pouch ◽  
Protein Tyrosine ◽  
Macromolecular Transport ◽  
Arteriolar Tone

We studied the interactions between platelet-activating factor (PAF) and protein tyrosine kinase (PTK) in the modulation of microvascular responses in the hamster cheek pouch using intravital microscopy and computer-assisted image analysis. Changes in arteriolar diameter and in integrated optical intensity (IOI; an index of vascular permeability) were measured. Fluorescein isothiocyanate-labeled dextran 150 (FITC-Dx 150) served as a tracer for macromolecular transport. Genistein and tyrphostin 25, two PTK inhibitors, were applied topically in separate experiments. Pretreatment with 10(-4), 10(-6), and 10(-8) M genistein and with tyrphostin 25 at 10(-5) and 10(-7) M attenuated the maximal increment in mean IOI (+/- SE) induced by PAF at 10(-7) M (19.9 +/- 5.3, 21.5 +/- 4.5, 58.5 +/- 11.4, 28.7 +/- 7.6, and 35.0 +/- 10.9 vs. 70.7 +/- 8.9 units, respectively). Pretreatment with PTK inhibitors resulted in vasodilation but did not inhibit PAF-induced vasoconstriction. Our results suggest that PTK represents a biochemical pathway involved in the PAF modulation of microvascular permeability but not PAF modulation of arteriolar tone.

Bradykinin- and substance P-induced edema formation in the hamster cheek pouch is tyrosine kinase dependent

2007 ◽  
Vol 103 (1) ◽  
pp. 184-189 ◽  
Author(s):  
Israel Rubinstein
Keyword(s):  
Substance P ◽  
Tyrosine Kinase ◽  
Intracellular Signaling ◽  
Protein Tyrosine Kinase ◽  
Cell Function ◽  
Cheek Pouch ◽  
Induced Responses ◽  
Hamster Cheek Pouch ◽  
Endothelial Cell Function ◽  
Protein Tyrosine

The purpose of this study was to determine whether protein tyrosine kinase, a ubiquitous family of intracellular signaling enzymes that regulates endothelial cell function, modulates bradykinin- and substance P-induced increase in macromolecular efflux from the intact hamster cheek pouch microcirculation. Using intravital microscopy, I found that suffusion of bradykinin or substance P (each, 0.5 and 1.0 μM) onto the cheek pouch elicited significant, concentration-dependent leaky site formation and increase in clearance of fluorescein isothiocyanate-dextran (FITC-dextran; molecular mass, 70 kDa; P < 0.05). These responses were significantly attenuated by suffusion of genistein (1.0 μM) or tyrphostin 25 (10 μM), two structurally unrelated, nonspecific protein tyrosine kinase inhibitors ( P < 0.05). Conceivably, the kinase(s) involved in this process could be agonist specific because genistein was more effective than tyrphostin 25 in attenuating bradykinin-induced responses while the opposite was observed with substance P. Both inhibitors had no significant effects on adenosine (0.5 M)-induced responses ( P > 0.5). Collectively, these data suggest that the protein tyrosine kinase metabolic pathway modulates, in part, the edemagenic effects of bradykinin and substance P in the intact hamster cheek pouch microcirculation in a specific fashion.

Protein-tyrosine Kinase p72 syk Is Activated by Platelet Activating Factor in Platelets

1994 ◽  
Vol 72 (06) ◽  
pp. 937-941 ◽  
Author(s):  
Karim Rezaul ◽  
Shigeru Yanagi ◽  
Kiyonao Sada ◽  
Takanobu Taniguchi ◽  
Hirohei Yamamura
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Critical Role ◽  
Platelet Activating Factor ◽  
Kinase Assay ◽  
Potential Candidate ◽  
Protein Tyrosine ◽  
Induced Aggregation

SummaryIt has been demonstrated that activation of platelets by platelet-activating factor (PAF) results in a dramatic increase in tyrosine phosphorylation of several cellular proteins. We report here that p72 syk is a potential candidate for the protein-tyrosine phosphorylation following PAF stimulation in porcine platelets. Immunoprecipitation kinase assay revealed that PAF stimulation resulted in a rapid activation of p72 syk which peaked at 10 s. The level of activation was found to be dose dependent and could be completely inhibited by the PAF receptor antagonist, CV3988. Phosphorylation at the tyrosine residues of p72 syk coincided with activation of yllsyk. Pretreatment of platelets with aspirin and apyrase did not affect PAF induced activation of p72 syk .Furthermore, genistein, a potent protein-tyrosine-kinase inhibitor, diminished PAF-induced p72 syk activation and Ca2+ mobilization as well as platelet aggregation. These results suggest that p72 syk may play a critical role in PAF-induced aggregation, possibly through regulation of Ca2+ mobilization.

Resistance and exchange microvessels are modulated by different PAF receptors

1991 ◽  
Vol 261 (5) ◽  
pp. H1648-H1652 ◽  
Author(s):  
A. C. Tomeo ◽  
W. N. Duran
Keyword(s):  
Platelet Activating Factor ◽  
Fluorescein Isothiocyanate ◽  
Fold Increase ◽  
Cheek Pouch ◽  
Receptor Sensitivity ◽  
Hamster Cheek Pouch ◽  
Vasoconstrictor Response ◽  
Paf Receptor ◽  
Fluorescein Isothiocyanate Dextran ◽  
Arteriolar Diameter

Using several platelet activating factor (PAF) receptor antagonists, we investigated whether a differential receptor sensitivity to PAF exists between the arteriolar and venular segments of the microcirculation. The microvascular bed of the hamster cheek pouch was observed with intravital fluorescent television microscopy. Alterations in arteriolar diameter and in the clearance of fluorescein isothiocyanate-dextran (FITC-Dx 150; mol wt 150,000) were measured in response to PAF. Topical application of 10(-7) M PAF elicits a 10-fold increase in FITC-Dx 150 clearance (mean +/- SE = 9,172 +/- 1,289 nl.2 h-1.g-1) compared with control and vasoconstricts arterioles (20-40 microns) to approximately 50% their control diameters. Pretreatment with WEB 2086 (2 mg/kg iv) or SDZ 63-675 (10 mg/kg iv) blocks PAF-induced vasoconstriction and significantly attenuates the clearance of FITC-Dx 150 evoked by PAF, producing mean clearance values of 2,164 +/- 604 and 3,648 +/- 262 nl.2 h-1.g-1 respectively. L-659,989 (2 or 10 mg/kg iv) and SDZ 63-675 (5 mg/kg iv) abolished the vasoconstrictor response but not the postcapillary venular permeability response to PAF. These data suggests the presence of heterogeneous PAF receptors between the pre- and postcapillary segments of the microcirculation.

Role of nitric oxide in leukotriene C4-induced increases in microvascular transport

1993 ◽  
Vol 265 (1) ◽  
pp. H409-H414 ◽  
Author(s):  
W. G. Mayhan
Keyword(s):  
Nitric Oxide ◽  
Fluorescent Microscopy ◽  
Fluorescein Isothiocyanate ◽  
Cheek Pouch ◽  
Leukotriene C4 ◽  
Hamster Cheek Pouch ◽  
Macromolecular Transport ◽  
Transport Of Macromolecules

The goal of this study was to determine the role of nitric oxide in alterations in macromolecular transport of the hamster cheek pouch in vivo in response to leukotriene C4. We used intravital fluorescent microscopy to examine the transport of macromolecules across the hamster cheek pouch in response to leukotriene C4 before and after application of an enzymatic inhibitor of nitric oxide, NG-monomethyl-L-arginine (L-NMMA; 1.0 microM). Increases in transport of macromolecules across the hamster cheek pouch were quantitated by the formation of venular leaky sites and clearance of fluorescein isothiocyanate-dextran (FITC-dextran; mol wt = 70 K). Leukotriene C4 (1.0 and 3.0 nM) produced an increase in the number of venular leaky sites and clearance of FITC-dextran-70K. Superfusion of L-NMMA (1.0 microM) significantly decreased leukotriene C4-induced increases in venular leaky sites and clearance of FITC-dextran-70K. In addition, superfusion of LY-83583 (10 microM) significantly decreased leukotriene C4-induced increases in venular leaky sites. In contrast, superfusion of NG-monomethyl-D-arginine (D-NMMA; 1.0 microM), indomethacin (10 mg/kg iv), or diphenhydramine hydrochloride; 15–20 mg/kg iv) did not significantly alter leukotriene C4-induced increases in venular leaky sites. Thus these findings suggest that production of nitric oxide and subsequent activation of guanylate cyclase play an important role in formation of venular leaky sites and clearance of FITC-dextran-70K in response to application of leukotriene C4.

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