Arachidonate transport through the blood-retina and blood-brain barrier of the rat during aging.

The permeability-surface area product (PS) of [I-14C]arachidonate at the blood-retina (BRB) and blood-brain barrier (BBB) was determined after short carotid perfusion in Wistar rats at 4, 12 and 28 months of age. For the visual system structures, parietal and frontal cortex, striatum, hypothalamus, hippocampus and olfactory bulb there was no significant difference among mean PSs in any age group. Our results indicate that: (1) arachidonate is able to cross at relevant rate BRB and BBB; (2) in all brain regions except retina, optic tract and hippocampus, blood barriers have a transport capacity for arachidonate significantly higher than that for docosahexaenoate and palmitate as well; (3) aging does not affect influx into retina and other structures of rat central nervous system of the arachidonate, a metabolic substrate rapidly incorporated into microcapillary and brain lipids, and for which simple diffusion transport across the BRB and BBB may be postulated.