Dynamic analysis of gravimetric response of isolated dog hindlimb

Previous gravimetric studies of transcapillary fluid movement have been based on capillary filtration coefficient (CFC) estimates. In these studies only a single CFC value is estimated for the entire isolated vascular bed. We have analyzed the dynamic gravimetric responses of isolated dog hindlimb to venous pressure steps and found it possible to estimate two different CFC values. Under control conditions, one CFC value averaged .0049 ml/mmHg min per 100g tissue wt, whichagrees with results of previous investigators. The other CFC value averaged 90304, which is very close to estimates we have previously made by an independent frequency-response methods. Changes in hindlimb properties to intra-arterial infusions of acetylcholine, papaverine, isoproterenol, and norepinephrine were also studied. Drug infusion results and the presence of similar dynamic components in experiments on gracilis muscle support the existence of inhomogeneous pathwaysin tissue, which lead to fluid-exchange nonuniformity.