title: Differential changes in central monoaminergic metabolism during first and multiple sodium depletions in rats.
abstract: To investigate the role of central monoamines in the behavior of sodium appetite, serotonergic and dopaminergic metabolism in regions of the forebrain and dorsal hindbrain were measured in sodium-depleted rats. Male Sprague-Dawley rats were sodium depleted by injection of the diuretic-natriuretic drug, Lasix (furosemide, 10 mg), and maintained on a sodium-deficient diet overnight. Rats were tested at a first sodium depletion or after multiple sodium depletions. There were three test conditions: 1) mock depletion consisted of vehicle injection and overnight sodium-deficient diet; 2) sodium depletion alone consisted of Lasix injection and overnight sodium-deficient diet; and 3) intake of NaCl following sodium depletion consisted of 9-min access to 0.3 M NaCl after Lasix injection and overnight sodium-deficient diet. Dopamine (DA), DOPAC, HVA, 5-HT, and 5-HIAA were measured by HPLC in the olfactory tubercle, amygdala-pyriform lobe, n. accumbens, hypothalamus, caudate nucleus, and the dorsal hindbrain. Ingestion of 0.3 M NaCl for 9 min after the first sodium depletion increased 5-HIAA/5-HT ratio significantly in the n. accumbens and amygdala, and increased DOPAC/DA ratio in the n. accumbens and olfactory tubercle compared to the mock treatment. In contrast to the results after the first sodium depletion, rats that ingested 0.3 M NaCl after four or more sodium depletions had no changes in 5-HT and DA metabolism in the forebrain, but they did have a significantly larger 5-HIAA/5-HT ratio in the dorsal hindbrain than mock-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Psychiatry, Cornell University Medical College, White Plains, NY.
authors.forename: S P
authors.initials: SP
authors.lastname: Frankmann
authors.forename: L
authors.initials: L
authors.lastname: Broder
authors.forename: J H
authors.initials: JH
authors.lastname: Dokko
authors.forename: G P
authors.initials: GP
authors.lastname: Smith
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001835:Body Weight / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000378:metabolism; D004435:Eating / Q000187:drug effects; D004563:Electrochemistry; D005665:Furosemide / Q000494:pharmacology; D006719:Homovanillic Acid / Q000378:metabolism; D008297:Male; D016548:Prosencephalon / Q000033:anatomy & histology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012249:Rhombencephalon / Q000033:anatomy & histology / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D012964:Sodium / Q000502:physiology*
chemical_list: D015306:Biogenic Monoamines; D015102:3,4-Dihydroxyphenylacetic Acid; D012701:Serotonin; D005665:Furosemide; D012964:Sodium; D004298:Dopamine; D006719:Homovanillic Acid