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Updated: Jul 8, 2026
Quantitation of Endothelial Cell Adhesiveness In Vitro
Published on: June 18, 2015
Leukocyte adherence in rat mesenteric venules: effects of adenosine and methotrexate
H Asako1, R E Wolf, D N Granger
1Department of Physiology, Center of Excellence for Arthritis and Rheumatology, Louisiana State University Medical Center, Shreveport.
Background:
Methotrexate (MTX) reduces neutrophil adhesion to endothelial cell monolayers, possibly via stimulation of adenosine production. However, it remains unclear whether adenosine participates in the anti-inflammatory actions of MTX in postcapillary venules.
Methods:
Leukocyte-endothelial cell adhesive interactions were measured in rat mesenteric venules (25-35 microns diameter) during superfusion with either bicarbonate-buffered saline (BBS) alone, BBS combined with platelet-activating factor (PAF), or BBS combined with leukotriene B4 (LTB4). In some experiments, either MTX or adenosine was added to a superfusate containing either PAF or LTB4. In other experiments, either adenosine deaminase (ADA), an adenosine A1-receptor antagonist, or an A2-receptor antagonist was added to a superfusate containing PAF and either MTX or adenosine.
Results:
Both MTX and adenosine were effective in preventing the leukocyte-endothelial cell adhesive interactions elicited by PAF, but not by LTB4. These actions of adenosine and MTX against PAF-induced leukocyte adhesion were blunted by ADA and the A2-(but not the A1-) receptor antagonist.
Conclusions:
These results indicate that both adenosine and methotrexate attenuate PAF-induced leukocyte-endothelial cell adhesion in postcapillary venules via activation of A2-receptors on the leukocyte.
