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Transfer of 45 Ca and 36 Cl at the blood‐nerve barrier of the sciatic nerve in rats fed low or high calcium diets
Author(s) -
Wadhwani K. C.,
Murphy V. A.,
Rapoport S. I.
Publication year - 1991
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490280413
Subject(s) - chemistry , sciatic nerve , medicine , endocrinology , paracellular transport , calcium , mannitol , blood–brain barrier , permeability (electromagnetism) , central nervous system , biochemistry , membrane
Unidirectional fluxes of 45 Ca, 36 C1, of [ 3 H]mannitol from blood into the sciatic nerve and cerebral cortex were determined from 5‐ and 15‐min uptakes of these tracers after an intravenous (i.v.) bolus injection in awake rats. Rats were fed diets for 8 wk, that had either a low (0.01%wt/wt), normal (0.67%), or high (3%) Ca content. Plasma[Ca] was 32% less and 11% more in rats fed low (LOCA) and high Ca diets (HICA), respectively, than in rats fed a normal Ca diet (CONT). The mean permeability‐sur‐face area product (PA) of 45 Ca at the blood‐nerve barrier was about eightfold higher than at the blood‐brain barrier in the same animals and did not differ significantly between groups (<0.05). Mean PA ratios of 45 Ca/ 36 Cl barriers in CONT rats, 0.52±0.04 and 0.40±0.02, respectively, were not significantly different from corresponding ratios in LOCA and HICA groups, and corresponded to the aqueous limiting diffusion ratio (0.45), Our results show no evidence for concentration‐dependent transport of Ca over a plasma [Ca] range of 0.8‐1.4 mmol/liter at the blood‐nerve barrier of the rat peripheral nerve, and suggest that Ca and Cl exchange slowly between nerve and blood via paracellular pathways.