Effect of a specific platelet-activating factor antagonist on cardiovascular and peripheral cellular responses to colonic ischemia and reperfusion in anesthetized ponies.
The role of platelet-activating factor in mediating the cardiovascular and peripheral cellular responses to large-colon ischemia and reperfusion, was explored in anesthetized ponies. A specific platelet-activating factor (PAF) antagonist (WEB 2086) was administered to a group of 6 ponies, and another 6 ponies (controls) were given an equivalent volume of saline solution, prior to 1 hour of large-colon torsion. After correction of the torsion, ponies were monitored during the reperfusion period. Significant (P < 0.05) hypotension and metabolic acidosis developed in all ponies after correction of colonic torsion, cardiac index increased initially, but then decreased significantly (P < 0.05) over the study period. Mean times between correction of torsion and onset of cardiac failure and death were not different between groups. Significant (P < 0.05) thrombocytopenia developed during the reperfusion period in control ponies, but not in WEB-treated ponies. Blood leukocyte concentration in control ponies was more variable and significantly (P < 0.05) decreased immediately upon reperfusion, compared with that in WEB-treated ponies. We conclude that although the cardiovascular responses to colonic ischemia and reperfusion are not prevented by use of a specific PAF-antagonist, specific peripheral cellular responses are mediated by PAF.
Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48824.
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Wilson
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Stick
D000704:Analysis of Variance; D000818:Animals; D001381:Azepines / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003106:Colon / Q000098:blood supply*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006736:Horses; D007511:Ischemia / Q000503:physiopathology*; D007958:Leukocyte Count / Q000187:drug effects; D008297:Male; D009919:Orchiectomy; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors*; D011652:Pulmonary Circulation / Q000187:drug effects; D015424:Reperfusion; D014230:Triazoles / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects
D001381:Azepines; D010972:Platelet Activating Factor; D014230:Triazoles; C052518:WEB 2086