Abstract

The high functional plasticity of the glutamatergic synapse of the vestibular epithelium is supported by a delicate balance of excitatory and inhibitory interactions. One of the peptides co-localized with acetylcholine (ACh) in the efferent fibers is dopamine. Using external perfusion of the synaptic zone and multiunit recording of an afferent fibers activity the effect of dopamine antagonists on the background firing rate of the semicircular canal sensory fibers was studied on the isolated frog vestibular. The present research revealed that the dopamine receptor antagonist (D1) SCH-23390 significantly reduced the level of background activity at high concentrations. In contrast, D2 antagonist eticlopride caused positive-negative answer of the background activity of the sensory fibers in dose-depending manner. The data confirm the hypothesis that dopamine, being tonic released from the efferent fibers, realizes neuroprotective inhibitory control over the afferent glutamatergic synapse activity in the vestibular epithelium via D1 and D2 receptors.

中文翻译：

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多巴胺受体拮抗剂D1和D2确定了青蛙前庭神经保护作用的不同机制。

摘要

前庭上皮的谷氨酸能突触的高功能可塑性受到兴奋性和抑制性相互作用的微妙平衡的支持。与乙酰胆碱（ACh）共同定位的传出纤维中的一种肽是多巴胺。使用突触区的外部灌注和传入纤维活性的多单位记录，在孤立的青蛙前庭上研究了多巴胺拮抗剂对半规管感觉纤维本底发射率的影响。本研究表明，多巴胺受体拮抗剂（D1）SCH-23390在高浓度下显着降低了背景活性水平。相反，D2拮抗剂艾替洛必利以剂量依赖性方式引起感觉纤维本底活性的正负应答。