Schlicker E, Fink K, Detzner M, Göthert M
Institut für Pharmakologie und Toxikologie, Rheinische Freidrich-Wilhelms-Universität, Bonn, Federal Republic of Germany.
J Neural Transm Gen Sect. 1993;93(1):1-10. doi: 10.1007/BF01244933.
In superfused mouse striatal slices preincubated with [3H]dopamine 25 nmol/l, the electrically (3 Hz) evoked tritium overflow was inhibited by histamine 10 mumol/l by 18%. The degree of inhibition was increased to 38% by haloperidol but not affected by (1) atropine, (2) reducing the stimulation frequency to 0.3 Hz or (3) increasing the concentration of [3H]dopamine (used for preincubation) to 100 nmol/l. The effect of histamine was mimicked by the H3 agonist R-(-)-alpha-methylhistamine; it was not affected by the H1 antagonist dimetindene and the H2 antagonist ranitidine but abolished by the H3 antagonist thioperamide. Tritium overflow evoked by Ca2+ ions (introduced into Ca(2+)-free, K(+)-rich medium containing tetrodotoxin) was not affected by histamine 10 mumol/l in the absence, but inhibited (by 30%) in the presence of haloperidol; the effect of histamine was abolished by thioperamide. In conclusion, the dopaminergic nerve terminals in the mouse striatum are endowed with presynaptic H3 receptors. Simultaneous blockade of dopamine autoreceptors increases the extent of the H3 receptor-mediated inhibition of dopamine release.
在预先用25 nmol/l [3H]多巴胺孵育的灌流小鼠纹状体切片中，10 μmol/l组胺可使电刺激（3 Hz）诱发的氚外流减少18%。氟哌啶醇可使抑制程度增加至38%，但不受以下因素影响：（1）阿托品；（2）将刺激频率降至0.3 Hz；（3）将（用于预孵育的）[3H]多巴胺浓度增至100 nmol/l。H3激动剂R-(-)-α-甲基组胺可模拟组胺的作用；它不受H1拮抗剂二甲茚定和H2拮抗剂雷尼替丁的影响，但可被H3拮抗剂硫代哌啶消除。在不含河豚毒素的无钙、富钾培养基中引入Ca2+离子诱发的氚外流，在无组胺时不受10 μmol/l组胺影响，但在有氟哌啶醇时受到抑制（30%）；组胺的作用可被硫代哌啶消除。总之，小鼠纹状体中的多巴胺能神经末梢具有突触前H3受体。同时阻断多巴胺自身受体可增加H3受体介导的多巴胺释放抑制程度。
