Abstract
Permeability‐surface area products (PAs) of the blood‐nerve barrier (BNB) and blood‐brain barrier (BBB) to ^125^I‐labeled native bovine serum albumin (nBSA, pI ∼︁4), and to 2 cationized albumins (cBSA) of differing pI (pI ∼︁ 8 and 11), were quantitatively determined in awake rats, using an i.v. bolus injection technique. Mean PAs of the BNB and BBB to ^125^I‐nBSA, after a circulation time of up to 120 min, were (0.17 ± 0.23) and (0.09 ± 0.05) × 10^−5^ ml/s.g. wet wt, respectively (n =; 12 rats), and were not significantly different from 0 (P > 0.05). Mean PAs of the BNB and BBB to ^125^I‐cBSA (pI ∼︁ 8), after circulation time of 12 min, were (1.9 ± 0.1) and (1.7 ± 0.1) × 10^−5^ ml/s.g wet wt, respectively (n =; 8). Significant greater PAs, at both the BNB and BBB to ^125^I‐cBSA (pI ∼︁ 11) [(8.2 ± 1.8) and (3.0 ± 0.6) × 10^−5^ ml/s.g wet wt, respectively (n =; 12)], than both PA's of nBSA and cBSA (pI ∼︁ 8) were found. The accumulation of ^125^I‐cBSA in epi‐perineurial tissues also was higher than that of ^125^I‐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. © 1992 Wiley‐Liss, Inc.