We studied dura mater (DM) permeability of spinal cord canine in vitro for the low-molecular components of blood serum - urea, creatinine, glucose, lactate, cholesterol, calcium, and inorganic phosphate. We evaluated DM permeability for high-molecular compound of blood serum - albumin as a comparison marker. As established, most of the studied components had the permeability within 8-15 %. Maximum DM permeability was found for lactate (33.6 %), minimum one - for cholesterol (1.3 %). The permeability for urea and for creatinine was 8.0 and 7.5 %, respectively; and herewith the permeability non-linear dependence on the initial substrate concentration in blood serum was observed. DM threshold permeability for urea was 4.83 mmol/L, for creatinine - 97 μmol/L. The functional characteristics of DM permeability can be determined by its structural features - close packing of fibrillar structures connective tissue, high content of sulfated glycosaminoglycans, and the absence of non-sulfated ones.