Biochemical evidence for activation of specific monoanine pathways by ethanol

S. A. Khatib, J. M. Murphy, W. J. McBride

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Abstract

The effects of an acute intraperitoneal (IP) low (0.5 g/kg) or high (2.5 g/kg) dose of ethanol on the contents of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in 7 selected CNS regions of the rat were examined after 15, 30 and 60 minutes. The IP administration of 0.5 g/kg ethanol produced blood alcohol concentrations (BACs) of 41±4, 40±4 and 15±1 mg% (N=8 each) after 15, 30 and 60 minutes, respectively. This low dose of ethanol did not alter the levels of DA, DOPAC, HVA, 5-HT and 5-HIAA in any of the 7 CNS regions at any of the time points examined. The dose of 2.5 g/kg ethanol produced BACs of 254±26, 268±20 and 282±10 mg%(N=8 each) after 15, 30 and 60 minutes, respectively. This high dose of ethanol did not alter the contents of DA and 5-HT in any of the regions examined at any of the times, except for a 30% increase in the content of DA in the posterior striatum after 60 minutes. The administration of 2.5 g ethanol/kg elevated the levels of DOPAC and/or HVA 25 to 70% over saline control values in the (a) nucleus accumbens (ACC) and hypothalamus (HYPO) after 15, 30 and 60 minutes, and (b) posterior striatum (PSTR), lateral septal nucleus (LSN) and frontal cortex (FCTX) after 60 minutes. The contents of DOPAC and/or HVA were not altered by the high dose of ethanol in either the thalamus or olfactory bulbs. The administration of 2.5 g ethanol/kg increased the contents of 5-HIAA 20 to 25% above control values in the ACC and PSTR only after 60 minutes. The high dose of ethanol did not alter the level of 5-HIAA in any of the other 5 regions examined. The higher CNS levels of DOPAC and/or HVA at BACs of approximately 250 mg% suggest enhanced activity of DA projections (a) from the ventral tegmental area to the ACC, LSN and FCTX; (b) from the substantia nigra to the PSTR; and (c) within the incertohypothalamic system. The elevated contents of 5-HIAA in the ACC and PSTR suggest increased activity of the 5-HT dorsal ascending pathway from the dorsal raphe nucleus.

Original languageEnglish (US)
Pages (from-to)295-299
Number of pages5
JournalAlcohol
Volume5
Issue number4
DOIs
StatePublished - Jan 1 1988

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Keywords

  • 3,4-Dihydroxyphenylacetic acid levels
  • 5-Hydroxyindoleacetic acid levels
  • Acute ethanol administration
  • Dopamine metabolism
  • Homovanillic acid levels
  • Serotonin metabolism

ASJC Scopus subject areas

  • Biochemistry
  • Medicine(all)
  • Neuroscience(all)
  • Behavioral Neuroscience
  • Toxicology
  • Health(social science)

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