Effects of ethanol on extracellular amino acid levels in high-and low-alcohol sensitive rats: a microdialysis study

Selectively bred high-alcohol sensitive (HAS) and low-alcohol sensitive (LAS) rats possess a number of behavioural and electrophysiological differences in their responses to alcohol. Using a microdialysis technique, we have evaluated whether the levels of the amino acids aspartate, glutamate, arginine, taurine, and alanine in HAS and LAS rats differ in their response to ethanol administration (2 g/kg, i.p.). The basal concentrations of each amino acid in these two groups were statistically similar. Following ethanol injection, alanine, arginine, and glutamate were significantly decreased in HAS rats, whereas, alanine, glutamate, and taurine were significantly increased in LAS rats by the end of the experiment. Interestingly, an increase in the sulphonated amino acid taurine was only evident 20 min after ethanol administration in the HAS rats, when compared to saline controls. No changes were observed in the other amino acids studied, aspartate and glycine, after ethanol administration. These data suggest that, in addition to differential behavioural responses to alcohol, HAS and LAS rats also differ in their neurochemical responses to ethanol.