Restoration of post-thrombotic peripheral collateral circulation in the cat by ketanserin, a selective 5-HT2-receptor...

In cats, an acute thrombotic obstruction of the aorta inducing continuous platelet activation, was produced by permanent ligation above the trifurcation, temporary ligation below the caudal mesenteric artery and production of a stasis thrombus in the segment. Before, 5 min, 24 hr and 48 hr after surgery, plethysmographic systolic blood pressure in fore- and hindlegs, and clinical scoring of the hindleg function were performed; at 72 hr, venous occlusion plethysmography for quantification of blood flow was performed and collateral vascular resistance was calculated. Thrombotic occlusion resulted in a loss of adequately functioning collateral circulation as evidence by the changes in both the objective and the clinical parameters. Pre-treatment with ketanserin (1.25 mg/kg i.p. daily) significantly improved the objective circulation parameters blood pressure ratio, blood flow and collateral vascular resistance and restored the clinically scored function of post-thrombotic collateral function. Provided platelet activation contributes to human vascular pathology, a similar mechanism may be involved in the potential effect of ketanserin in man.