Enhanced permeabilities of cationized-bovine serum albumins at the blood-nerve and blood-brain barriers in awake rats.

Permeability-surface area products (PAs) of the blood-nerve barrier (BNB) and blood-brain barrier (BBB) to 125I-labeled native bovine serum albumin (nBSA, pI approximately 4), and to 2 cationized albumins (cBSA) of differing pI (pI approximately 8 and 11), were quantitatively determined in awake rats, using an i.v. bolus injection technique. Mean PAs of the BNB and BBB to 125I-nBSA, after a circulation time of up to 120 min, were (0.17 +/- 0.23) and (0.09 +/- 0.05) x 10(-5) ml/s.g. wet wt, respectively (n = 12 rats), and were not significantly different from 0 (P greater than 0.05). Mean PAs of the BNB and BBB to 125I-cBSA (pI approximately 8), after circulation time of 12 min, were (1.9 +/- 0.1) and (1.7 +/- 0.1) x 10(-5) ml/s.g wet wt, respectively (n = 8). Significant greater PAs, at both the BNB and BBB to 125I-cBSA (pI approximately 11) [(8.2 +/- 1.8) and (3.0 +/- 0.6) x 10(-5) ml/s.g wet wt, respectively (n = 12)], than both PA's of nBSA and cBSA (pI approximately 8) were found. The accumulation of 125I-cBSA in epi-perineurial tissues also was higher than that of 125I-nBSA, and was related to the degree of cationization. Our results indicate that, as at the BBB, the transfer of cationized serum albumin is enhanced over that of native albumin at the BNB of the mammalian peripheral nerve.