Permeability of the Dura Mater of the Spinal Cord in Dogs for Low Molecular Weight Substances in Serum

摘要

The permeability of the dura mater (DM) of the dog spinal cord for low molecular weight serum components - urea, creatinine, glucose, lactate, cholesterol, calcium, and inorganic phosphate - was studied in in vitro conditions. DM permeability for a high molecular weight serum component - albumin - was assessed as a reference compound. Most of the study components had permeabilities of 8-15%. The greatest DM permeability was for lactate (33.6%) and the lowest was for cholesterol (1.3%). Values for urea and creatinine were 8.0 and 7.5%, respectively; there was a nonlinear relationship between permeability and the initial substrate concentration in the serum. The DM permeability threshold for urea was 4.83 mM and that for creatinine was 97 μM. The functional characteristics of DM permeability may be determined by its structural features - dense packing of fibrillar connective tissues structures, high content of sulfated and the absence of nonsulfated glycosaminoglycans.