Westerink B H, Hofsteede R M, Tuntler J, de Vries J B
Department of Medicinal Chemistry, University of Groningen, The Netherlands.
J Neurochem. 1989 Mar;52(3):722-9. doi: 10.1111/j.1471-4159.1989.tb02514.x.
Dopamine was determined by microdialysis of the striatum of conscious rats. We investigated whether the release of dopamine, induced by nine different pharmacological treatments, was sensitive to calcium antagonism. Calcium antagonism was determined by Mg2+ or Cd2+ infusion. The following conditions were investigated: haloperidol, haloperidol plus GBR 12909, nomifensine, (+)-amphetamine (all administered intraperitoneally), KCl, 1-methyl-4-phenyl-pyridinium ion (MPP+), glutamate, ouabain, and 120 mmol/L magnesium (all applied by infusion through the dialysis membrane). The results on calcium antagonism were combined with data on tetrodotoxin (TTX) sensitivity. With the combined data, three different types of dopamine release were characterized. First, action potential-dependent dopamine release was observed in animals treated with saline, haloperidol, haloperidol plus GBR 12909, nomifensine, and ouabain. Second, action potential-independent release was established in the case of (+)-amphetamine, glutamate, MPP+, and 120 mmol/L Mg2+. Finally, K+-induced dopamine release was classified as TTX independent and calcium dependent. It is concluded that brain dialysis is a powerful method for differentiating between different types of neurotransmitter release.
通过对清醒大鼠纹状体进行微透析来测定多巴胺。我们研究了九种不同药物处理诱导的多巴胺释放是否对钙拮抗敏感。通过输注Mg2+或Cd2+来测定钙拮抗作用。研究了以下几种情况：氟哌啶醇、氟哌啶醇加GBR 12909、诺米芬辛、（+）-苯丙胺（均腹腔注射）、氯化钾、1-甲基-4-苯基吡啶离子（MPP+）、谷氨酸、哇巴因以及120 mmol/L镁（均通过透析膜输注）。将钙拮抗作用的结果与河豚毒素（TTX）敏感性的数据相结合。利用这些综合数据，对三种不同类型的多巴胺释放进行了表征。首先，在用生理盐水、氟哌啶醇、氟哌啶醇加GBR 12909、诺米芬辛和哇巴因处理的动物中观察到了依赖动作电位的多巴胺释放。其次，在（+）-苯丙胺、谷氨酸、MPP+和120 mmol/L Mg2+的情况下确定了不依赖动作电位的释放。最后，钾离子诱导的多巴胺释放被归类为不依赖TTX且依赖钙。结论是脑透析是区分不同类型神经递质释放的有力方法。
