title: Sodium-dependent transport of sugars and iodide from the cerebral venticles of the rabbit.
abstract: 1. The objective was to discover whether the extraction of sugars and iodide from the perfused cerebral ventricles is Na(+)-dependent.2. In the ventriculo-aqueductal and ventriculo-cisternal perfusion systems in the rabbit the extraction of (14)C-labelled D-hexoses (glucose, 3-O-methyl-glucose, alpha-methyl-glucoside and galactose), (131)I(-) and (24)Na was inhibited when 82% of the Na(+) in the perfusion fluid was replaced by choline. The extraction returned to control levels when the Na(+) concentration in the perfusion fluid was returned to normal.3. Ouabain, 5 x 10(-5)M in the perfusion fluid inhibited the extraction of the above (14)C sugars and (131)I(-), but hardly affected that of [(3)H]2-deoxy-D-glucose. It enhanced the extraction of (24)Na. C.s.f. production was usually totally inhibited.4. The extraction of [(14)C]urea remained unchanged during perfusion with low Na(+) fluid or ouabain.5. Recovery from brain of [(14)C]3-O-methyl-glucose, [(3)H]2-deoxy-glucose and (131)I(-) was low while recovery of [(14)C]alpha-methyl-glucoside and (24)Na was high. On an equal weight basis recovery of [(14)C]3-O-methyl-glucose was about twelve times higher from the choroid plexus than from the brain.6. Part of the movement of (14)C sugars may be explained on basis of a Na(+)-gradient hypothesis with involvement of the Na(+) pump at the blood-c.s.f. or blood-brain barriers.7. The rate of c.s.f. production from the first three ventricles comprised about 40% of the rate from all four ventricles. The extraction of sugars, urea and cations was similar in both perfusion systems while the extraction of (131)I(-) was higher in the ventriculo-cisternal system than in the ventriculo-aqueductal system.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D001921:Brain / Q000378:metabolism; D002250:Carbon Radioisotopes; D002552:Cerebral Ventricles / Q000378:metabolism*; D002555:Cerebrospinal Fluid / Q000378:metabolism; D002831:Choroid Plexus / Q000378:metabolism; D005260:Female; D006601:Hexoses / Q000378:metabolism*; D007454:Iodides / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D011817:Rabbits; D011868:Radioisotopes; D012964:Sodium / Q000502:physiology*; D012975:Sodium Isotopes
chemical_list: D002250:Carbon Radioisotopes; D006601:Hexoses; D007454:Iodides; D007457:Iodine Radioisotopes; D011868:Radioisotopes; D012975:Sodium Isotopes; D010042:Ouabain; D012964:Sodium