Effects of xylazine on glutamate and GABA contents in the hippocampus and thalamencephal in the rat
The purpose of the study was to define if anaesthetic action of xylazine could conceivably result from the potentiation of inhibitory neurotransmitters or the inhibition of excitatory neurotransmitter systems in the brain. Rats were injected with xylazine at a dose of 50 mg/kg b.w., and then the hippocampus and thalamencephal were removed at 0.1, 0.25, 0.5, 1, 1.5, 2, 4, and 6 h after the injection. Glutamate (Glu) and γ-aminobutyric-acid (GABA) were measured in the brain tissue by reversed-phase high-performance liquid chromatography. The results revealed that the hippocampus Glu level decreased significantly 0.1 h after the injection of xylazine, the thalamencephal GABA increased significantly 0.1 h after the injection, while the changes in hippocampus GABA and thalamencephal Glu were not significant. However, all of these changes returned to the normal level after 2 and 4 h, respectively. The results indicated the relative effects of xylazine on Glu and GABA levels in the hippocampus and thalamencephal.
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