Permeability of mammalian heart capillaries to sucrose and inulin

¹ Department of Physiology, University of Minnesota Medical School, Minneapolis, Minnesota

Rabbit hearts were perfused with modified Ringer's solution containing 10 g sucrose or inulin per liter. After various perfusion times, ventricular samples were analyzed for their content of the respective saccharide. The tissue content of sucrose rose to half its apparent maximum value in approximately 6 sec; the corresponding time for inulin was approximately 90 sec. We concluded that at the high perfusion rates employed (40 ml/min per heart) inulin permeation is limited by passage across the capillary membrane and is practically unaffected by perfusion rate and interstitial diffusion, while sucrose permeation is limited partly by passage across the capillary membrane and partly by perfusion rate. We calculated capillary permeability coefficients of 0.4 x 10^–5 cm/sec for inulin and 11 x 10^–5 cm/sec for sucrose.

Key Words: permeability of rabbit heart capillaries • capillary • permeability to nonelectrolytes • sucrose distribution volume • inulin distribution volume • permeability coefficient • inulin diffusion coefficient

Submitted on August 14, 1963