Takahashi A, Ikarashi Y, Ishimaru H, Maruyama Y
Department of Neuropsychopharmacology (Tsumura), Gunma University School of Medicine, Japan.
Neurosci Res. 1993 Oct;18(1):45-51. doi: 10.1016/0168-0102(93)90104-x.
Intraneuronal and extracellular dopamine (DA) metabolism in rat striatum during inhibition of neurotransmission processes by tetrodotoxin (TTX) perfusion was examined by analysis of the striatal DA content and the amount of initial post-mortem DA output. In spite of there being an excess amount of DA already present in the striatum, the contents of DA and its metabolites were increased time-dependently by TTX perfusion through a microdialysis membrane. A massive increase in extracellular level of DA occurred immediately after death. The amount of the post-mortem DA output was further increased in proportion to the preceding TTX perfusion time. The ratio of the amount of post-mortem DA output to the striatal DA content was also increased by previous perfusion with TTX. Verapamil, a Ca2+ channel blocker, delayed the appearance of the peak of the DA output. These results suggest that releasable DA accumulates in neurons during TTX perfusion, and that the early part of the DA output upon death reflects intraneuronal aspects of DA metabolism while the animal is alive.
通过分析纹状体多巴胺（DA）含量和死后初期DA释放量，研究了在河豚毒素（TTX）灌注抑制神经传递过程中大鼠纹状体的神经元内和细胞外DA代谢。尽管纹状体中已存在过量的DA，但通过微透析膜进行TTX灌注会使DA及其代谢产物的含量随时间增加。死后DA的细胞外水平立即大幅升高。死后DA释放量与之前TTX灌注时间成比例进一步增加。先前用TTX灌注也会使死后DA释放量与纹状体DA含量的比值增加。钙通道阻滞剂维拉帕米延迟了DA释放峰值的出现。这些结果表明，在TTX灌注期间可释放的DA在神经元中积累，并且死亡时DA释放的早期部分反映了动物存活时DA代谢的神经元内情况。
