Jaskiw George E, Newbould Erica, Bongiovanni Rodolfo
Psychiatry Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44141, USA.
Eur J Pharmacol. 2008 Jul 28;589(1-3):106-9. doi: 10.1016/j.ejphar.2008.06.018. Epub 2008 Jun 8.
Gamma-butyrolactone (GBL) elevates striatal and prefrontal cortex dopamine levels; only the striatal dopamine levels are elevated by increased dopamine synthesis. If increased dopamine synthesis is necessary in order for dopamine levels to be affected by tyrosine availability, then GBL-induced prefrontal cortex dopamine levels should be tyrosine insensitive. Rats received either vehicle, tyrosine (50 or 200 mg/kg i.p.) or a tyrosine-depleting mixture prior to GBL 750 mg/kg i.p.. GBL-induced dopamine levels in prefrontal cortex were lowered by tyrosine depletion. GBL-induced striatal dopamine levels were not affected. Hence, increased dopamine synthesis may not be necessary in order for tyrosine availability to affect pharmacologically elevated prefrontal cortex dopamine levels.
γ-丁内酯（GBL）可提高纹状体和前额叶皮质的多巴胺水平；只有纹状体多巴胺水平会因多巴胺合成增加而升高。如果多巴胺水平要受酪氨酸可用性的影响就必须增加多巴胺合成，那么GBL诱导的前额叶皮质多巴胺水平应该对酪氨酸不敏感。大鼠在腹腔注射750mg/kg GBL之前，分别接受溶剂、酪氨酸（50或200mg/kg腹腔注射）或酪氨酸消耗混合物。酪氨酸消耗降低了GBL诱导的前额叶皮质多巴胺水平。GBL诱导的纹状体多巴胺水平未受影响。因此，酪氨酸可用性要影响药理学上升高的前额叶皮质多巴胺水平，可能无需增加多巴胺合成。
