Effects of chronic ethanol treatment on monoamine levels in rat hippocampus and striatum.
We studied the effects of ethanol on concentrations of noradrenaline (NE), dopamine (DA) and serotonin (5-HT) and their metabolites in rat hippocampus and striatum. Ethanol (2 or 4 g/kg, po, from a 20% aqueous solution) was administered daily to male Wistar rats (4-13 per group) for 30 days and animals were sacrificed 30 min or 48 h after the last administration. Monoamines were measured by HPLC and considered significant at P < 0.05. A 47% increase in 5-HT levels was observed in the hippocampus with 4 g/kg ethanol in the 30-min protocol. Ethanol (2 and 4 g/kg) decreased DA (2114.5 +/- 126.4 and 1785.1 +/- 234.2 ng/g wet tissue, respectively) and 3,4-dihydroxyphenylacetic acid (DOPAC, 1477.6 +/- 132.1 and 1218.8 +/- 271.7 ng/g wet tissue, respectively) levels, while the higher dose also decreased NE (159.8 +/- 13.5), 5-HT (228.0 +/- 46.8) and 5-hydroxy-3-indoleacetic acid (5-HIAA, 304.4 +/- 37.2 ng/g wet tissue), in the striatum after a 48-h withdrawal as compared to controls (DA: 3063.9 +/- 321.3; DOPAC: 2379.6 +/- 256.0; NE: 292.8 +/- 50.2; 5-HT: 412.4 +/- 36.2; 5-HIAA: 703.9 +/- 61.4 ng/g wet tissue). In the 30-min protocol, ethanol (2 or 4 g/kg) decreased striatal NE (66 and 70%) and DA (50 and 36%) levels. On the other hand, increases were seen in 5-HIAA (146 and 153%) and 5-HT (59 and 86%) levels. Ethanol (2 g/kg, po) increased the homovanillic acid (HVA)/DA ratio (129%) in the striatum in the 30-min protocol, while at the higher dose it increased the HVA/DA ratio in the 48-h protocol (61%). These results indicate alterations in monoamines, mainly in the striatum, after chronic ethanol, which are influenced by dose and by the length of time after the last drug administration.
Vasconcelos
S M M
SM
Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
Cavalcante
R A
RA
Aguiar
L M V
LM
Sousa
F C F
FC
Fonteles
M M F
MM
Viana
G S B
GS
D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism; D013997:Time Factors
D002395:Catecholamines; D002492:Central Nervous System Depressants; D012701:Serotonin; D000431:Ethanol; D004298:Dopamine; D009638:Norepinephrine