High impact information on LOC518283

• Bradykinin-induced prostacyclin generation in endothelial cells was markedly reduced by the PAF receptor antagonists WEB 2086 or CV 6209 [1].
• This suggests that H. somni ChoP may induce platelet aggregation via interactions with the PAF receptor [2].
• Preincubation of the cells with the PAF receptor antagonist CV6209 (10(-6) M) inhibited the increase in [Ca2+]i. Ca(2+)-free medium (2 mM EGTA) totally abolished the sustained response to PAF, but it only partially inhibited the transient response [3].
• Mechanical stretch induces platelet-activating factor receptor gene expression through the NF-kappaB transcription factor [4].
• Moreover, in experiments using cycloheximide, we found that de novo protein synthesis was not necessary for the induction of the PAF receptor gene expression by mechanical stretch [4].

Biological context of LOC518283

• The increased PAF-R in endometrial stromal cells on day 20 of pregnant heifers was a pregnancy-specific effect and may mediate a local increase in endometrial vascular permeability known to precede the implantation [5].
• PAF-R levels were quantified in bovine oviductal epithelial and stromal cells and endometrial stromal cells at days 2 to 4, 12, and 20 of the estrous cycle and during early pregnancy [5].
• Each PAFr coding sequence (cds) in these three species is 1029 nucleotides long and contains no intervening sequences [6].
• Southern blotting results suggested that the PAFr gene exists as a single copy in the genome of pig [6].
• The expression of PAF-R and PAF-AH in immature but not mature TGC during gestation implicates a role for PAF in the differentiation, maturation and function of bovine placentomal TGC [7].

Anatomical context of LOC518283

• A significant increase (P < 0.05) in the portion of PAF-R-positive oviductal epithelial and stromal cells was detected in both non-pregnant and pregnant cattle on days 2 to 4 in comparison to day 12 and 20 [5].
• Positive binding of the anti-PAF-R antibody was found on the cell membrane and in the cytoplasm [5].
• During the oestrous cycle and early pregnancy, the oviduct and uterus undergo a variety of morphological and physiological modifications in which the platelet activating factor receptor (PAF-R) plays an important role [5].
• We suggest that the bovine endometrium produces PAF-like activity, expresses the PAF-R and possesses a PAF-AH activity which varies during pregnancy [8].
• PAF-R was localized mainly in luminal and glandular epithelium of the endometrium, but the staining was markedly increased in the endometrium of pregnant cows on day 20 compared to cyclic animals on the same day [8].

Associations of LOC518283 with chemical compounds

• Porcine, bovine and caprine PAFr genes cloned in BAC vectors were sequenced [6].
• Platelet-activating factor (PAF)-like activity, localization of PAF receptor (PAF-R) and PAF-acetylhydrolase (PAF-AH) activity in bovine endometrium at different stages of the estrous cycle and early pregnancy [8].
• The specific and competitive Paf receptor antagonists, WEB 2086 (0.1-1.0 microM) and CV 6209 (0.01-0.1 microM), inhibited Bk-, A23187- and, to a lesser extent, ATP-induced PGI2 generation but had no effect on basal PGI2 generation [9].
• Voltage-sensitive calcium channels do not appear to be involved in the influx of extracellular Ca2+ since verapamil had no effect on the PAF-induced increase in [Ca2+]i. The PAF receptor antagonist WEB 2086 inhibited the PAF-mediated effects on [Ca2+]i [10].
• The assay proved to be specific, since the PAF receptor antagonist SRI 63-441 inhibited platelet aggregation induced by culture media in dosages comparable to aggregation induced by synthetic PAF(18) [11].

Regulatory relationships of LOC518283

• Platelet-activating factor receptor (PAF-R) and acetylhydrolase (PAF-AH) are co-expressed in immature bovine trophoblast giant cells throughout gestation, but not at parturition [7].

Other interactions of LOC518283

• The lowest peak, which represented the predominant activity, was blocked by leukotriene B4-receptor antagonist (P < 0. 01) but not by platelet-activating factor-receptor antagonist [12].

Analytical, diagnostic and therapeutic context of LOC518283

• The PAF-R was detected in oviductal cells by using immunoblotting and immuno-gold postembedding method [5].
• Cells were grown in vitro and their intracellular PAF-R concentration was measured by flow cytometry using a polyclonal anti-PAF-R antibody system [5].
• Two major bands of PAF-R protein at 67 kDa and 97 kDa were detected by Western blot analysis [8].
• Northern blot and immunohistochemical analyses revealed increased PAF receptor expression at both the mRNA and protein levels after 1 h exposure of the cells to a 5% strain at a frequency of 1 Hz [4].
• Radioimmunoassay for the novel platelet activating factor receptor antagonist E5880 [13].

References