[Effects of chronic alcohol administration on changes of extracellular dopamine and serotonin concentration induced by methamphetamine--comparison of two different alcohol preference rat lines].Nihon Arukoru Yakubutsu Igakkai Zasshi. 2002 Dec; 37(6):555-76.NA
We have investigated the effects of single administration of methamphetamine (MAP) (1.0 mg/kg, i.p.), and of combined administration of ethanol (EtOH) (2.0 g/kg, i.v.) and MAP (1.0 mg/kg, i.p.) on striatal extracellular dopamine (DA) and serotonin (5-HT) levels in chronic alcohol treated rats using a brain-microdialysis method. We used two different lines of rats with high and low alcohol preferences, (high alcohol preference rat (HAP) and low alcohol preference rat (LAP), respectively), which were chronically fed an alcohol containing liquid diet for 6 to 8 weeks. The percent change in DA and 5-HT in striatum following single administration of MAP was significantly higher in control-fed LAP than HAP. However, in the alcohol-fed group, the percent changes in DA and 5-HT were significantly elevated in the alcohol-fed HAP compared to LAP. There were no significant increases in striatal extracellular DA and 5-HT in alcohol-fed LAP. In combined administration of MAP and EtOH, extracellular DA and 5-HT levels increased slightly following EtOH administration in chronic alcohol-fed rats, especially in HAP. Dramatic increases of DA and 5-HT levels were observed in alcohol-fed HAP following EtOH and MAP administration. The percent change in DA and 5-HT in alcohol-fed HAP was further elevated to 4667.7 +/- 1095.5% and 3116.9 +/- 1162.7% of the maximal change, respectively. These percent changes ware higher than that observed with a single administration of MAP. Meanwhile, LAP were less sensitive to the influence of chronic EtOH administration and to single administration of MAP. These results demonstrate that a chronic treatment of EtOH enhances the sensitivity to MAP in a high alcohol preference rat line, when two drugs were administrated simultaneously, and that a significant difference of responsiveness to abused drugs was indicated between these two lines. It is necessary to consider the alcohol preference when investigating the interaction of alcohol and/or other abused drugs.