The effect of ethanol on the brain catecholamine systems in female mice, rats, and guinea pigs

The effect of acute ethanol administration on the concentrations of dopamine (DA), norepinephrine (NE) and their metabolites (3,4-dihydroxyphenylacetic acid [DOPAC], homovanillic acid [HVA], 3,4-dihydroxyphenylglycol [DHPG] and 4-hydroxy-3-methoxyphenylglycol [HMPG]) in brains of female mice, rats, and guinea pigs were investigated. A subhypnotic dose (2 g/kg) or a hypnotic dose (4 g/kg) of ethanol was administered intraperitoneally and the animals were killed 45 min later. In the rat the DA levels were unchanged, while the NE concentrations were decreased after both doses of ethanol. The DA levels did not change in the mouse and guinea pig, while the concentrations of NE showed a minor decrease in the mouse but were unaffected in the guinea pig. After 4 g/kg of ethanol the DOPAC and HVA concentrations were elevated significantly in all three species, and after 2 g/kg the DOPAC levels were increased in the rat and guinea pig brains and the HVA levels in the mouse and guinea pig brains. In the mouse and rat brain the DOPAC + HVA concentrations indicated a dose response relationship: 4 g/kg was significantly more effective than 2 g/kg. The DHPG concentration increased in the rat brain after both 2 and 4 g/kg, while the HMPG concentrations increased significantly only after 2 g/kg. In the mouse and guinea pig the brain DHPG concentrations remained unchanged, while the HMPG concentrations increased after both 2 and 4 g/kg ethanol. These data suggest, that the turnover of both DA and NE was increased 45 min after a subhypnotic as well as after a hypnotic dose of ethanol in all three species studied.(ABSTRACT TRUNCATED AT 250 WORDS)