![]() Currently, there are no reported studies of ataxic effects of ethanol-taurine interactions. Several studies have reported that taurine (30–80 mg/kg) reduces the duration of ethanol-induced loss of righting reflex, however a putative taurine antagonist does not alter this effect ( Iida and Hikichi, 1976 Boggan et al., 1978 Ferko, 1987). ![]() However, similar doses of taurine (30, 45, and 60 mg/kg) enhance the stimulant effect of 2.0 g/kg ethanol. Low doses of taurine (30 and 45 mg/kg) have been reported to inhibit locomotor stimulation following a 1.0 g/kg dose of ethanol in Swiss-Webster mice ( Aragon et al., 1992). The stimulant and ataxic effects of ethanol have been related to reinforcing effects, while depressant effects have been related to aversive effects of higher ethanol doses ( Wise and Bozarth, 1987). Higher doses of ethanol decrease open-field locomotion and result in loss of the righting reflex in both strains. These doses produce ataxia in both strains. ![]() Moderate doses of ethanol (1–2 g/kg) increase open-field locomotion persistently in DBA/2J mice, but only transiently in C57BL/6J mice ( Crabbe et al., 1982). That C57BL/6J and DBA/2J strains of mice display strain-dependent responses to ethanol is well-established. Because taurine and ethanol appear to share some pharmacological effects, and acute ethanol administration increases extracellular taurine levels, taurine may play a role in the behavioral effects of ethanol. Acute ethanol administration (1–3 g/kg) increases extracellular taurine levels 50–100% in mouse and rat brain ( Olive, 2002). Taurine is the most abundant amino acid in brain extracellular fluid and may be effective at low- to mid-micromolar concentrations, similar to ethanol ( Olive, 2002). Direct injection of taurine into the central nervous system results in decreased locomotion, which peaks at approximately 20 min ( Sgaragli and Pavan, 1972 Baskin et al., 1974). Yet, taurine alone appears to exert an inhibitory effect in the brain ( Olive, 2002). Relatively high concentrations of taurine are found in popular energy drinks and such drinks are reported to enhance the positive effects of ethanol, possibly by reducing the depressant effects of ethanol ( Ferreira et al., 2004a). Taurine is a sulfonated β-amino acid found in high concentrations in brain and muscle tissue ( Olive, 2002). Further, results are inconsistent with the notion that taurine plays a major role in the locomotor, ataxic, or loss of righting effects of ethanol. In conclusion, the interaction between taurine and ethanol is subtle. In this experiment, taurine pretreatment significantly attenuated the locomotor-stimulating effect of ethanol in both strains (but to a greater extent in C57BL/6J mice) and appeared to reduce the ataxic effects of ethanol in C57BL/6J mice. In a second experiment, drug-naïve mice were assigned to one of four treatment groups: saline + saline, saline + ethanol (1.78 g/kg), taurine (1.78 g/kg) + saline, or ethanol + taurine. ![]() Although taurine did not appear to alter effects of ethanol on any measure in either strain, the development of tolerance to locomotor effects and sensitization to ataxic effects of ethanol in DBA/2J mice complicated interpretation of these results. In the first experiment, effects of various doses of taurine (0.3–3.0 g/kg), ethanol (1.0–4.2 g/kg), or taurine in combination with ethanol were assessed in a within-subjects design. Two strains of mice, C57BL/6J and DBA/2J mice, were used to examine potential strain differences. The present study was designed to explore interactions between taurine and ethanol on several behaviors including locomotion, ataxia, and loss of righting. Recently, taurine-containing beverages have been reported to enhance the euphoric effects of ethanol, though the extent of this effect and the role of taurine remain speculative. Taurine is an abundant amino acid in the brain that shares pharmacological effects and similar potency with ethanol.
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