title: Ascorbic acid concentration in the lateral hypothalamus is related to plasma osmolality.
abstract: Microdialysis was used to measure extracellular ascorbic and uric acid concentrations in the lateral hypothalamus of water-restricted rats as they drank distilled water or 1.5% NaCl. Other water-restricted rats, not implanted with microdialysis probes, were decapitated 2 h after beginning to drink these fluids. Rats were inverted and their blood was collected for measurements of plasma osmolality and percent hematocrit. Results showed that drinking distilled water produced a significant increase in the ascorbic acid concentration but not in the uric acid concentration. Drinking 1.5% NaCl produced a significant decrease in the uric acid concentration but not in the ascorbic acid concentration. Drinking distilled water decreased mean osmolality from 306.0 to 291.5 mOsm/kg, whereas drinking 1.5% NaCl maintained mean osmolality at water-restricted levels. These results indicate that the extracellular fluid concentration of ascorbic acid in the lateral hypothalamus rises in response to a fall in plasma osmolality.
authors.affiliation: Department of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Mason
authors.forename: B R
authors.initials: BR
authors.lastname: Dev
authors.forename: C R
authors.initials: CR
authors.lastname: Freed
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D004326:Drinking / Q000502:physiology; D004563:Electrochemistry; D007026:Hypothalamic Area, Lateral / Q000033:anatomy & histology / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D014527:Uric Acid / Q000097:blood; D014882:Water-Electrolyte Balance / Q000502:physiology
chemical_list: D014527:Uric Acid; D001205:Ascorbic Acid