MICROENDOSCOPY OF THE SYNOVIAL VASCULATURE IN THE RABBIT KNEE-JOINT

The functional morphology of the synovial vasculature in the rabbit kn ee joint was investigated using our technique of microendoscopy, which involves an in vivo microscopy via a 1.9-mm endoscope. In the vessels of the fibrous tissue of the joint capsule it was found that after in traarticular administration of epinephrine the blood Row and the vascu lar diameters decrease for 3-5 min. In the areolar part of the synovia l tissue, an external elevation of the intraarticular pressure causes collapse of the capillaries at 10-15 mm Hg, whereas the collapse press ure of the arterioles is 30-40 mm Hg. Intraarticular application of Ne uropeptide Y (NPY) leads to a marked vasoconstriction including the ar teriovenous anastomoses, whereas after epinephrine the arteriovenous a nastomoses remain patent or dilate during the arteriolar constriction phase. It is concluded that the technique of microendoscopy allows a v aluable in vivo investigation of the synovial microvasculature. (C) 19 95 Academic Press, Inc.