Department of Biological Sciences, Delaware Center for Neuroscience Research, Delaware State University, Dover, DE, USA.
Department of Electrical and Computer Engineering, Biomedical Engineering, Data Sciences Institute, University of Delaware, Newark, DE, USA.
J Neurosci Res. 2022 Aug;100(8):1551-1559. doi: 10.1002/jnr.24965. Epub 2021 Nov 8.
Modulatory mechanisms of neurotransmitter release and clearance are highly controlled processes whose finely tuned regulation is critical for functioning of the nervous system. Dysregulation of the monoamine neurotransmitter dopamine can lead to several neuropathies. Synaptic modulation of dopamine is known to involve pre-synaptic D2 auto-receptors and acid sensing ion channels. In addition, the dopamine membrane transporter (DAT), which is responsible for clearance of dopamine from the synaptic cleft, is suspected to play an active role in modulating release of dopamine. Using functional imaging on the Caenorhabditis elegans model system, we show that DAT-1 acts as a negative feedback modulator to neurotransmitter vesicle fusion. Results from our fluorescence recovery after photo-bleaching (FRAP) based experiments were followed up with and reaffirmed using swimming-induced paralysis behavioral assays. Utilizing our numerical FRAP data we have developed a mechanistic model to dissect the dynamics of synaptic vesicle fusion, and compare the feedback effects of DAT-1 with the dopamine auto-receptor. Our experimental results and the mechanistic model are of potential broader significance, as similar dynamics are likely to be used by other synaptic modulators including membrane transporters for other neurotransmitters across species.
神经递质释放和清除的调节机制是高度受控的过程，其精细调节对于神经系统的功能至关重要。单胺递质多巴胺的失调可导致多种神经病变。已知突触调节多巴胺涉及到突触前 D2 自身受体和酸感应离子通道。此外，多巴胺膜转运蛋白（DAT）负责从突触间隙清除多巴胺，它被怀疑在调节多巴胺释放中发挥积极作用。我们使用秀丽隐杆线虫模型系统进行功能成像，表明 DAT-1 作为一种负反馈调节剂来调节神经递质囊泡融合。我们使用荧光恢复后光漂白（FRAP）的实验结果进行了后续研究，并通过游泳诱导瘫痪行为测定实验进行了再次确认。我们利用数值 FRAP 数据开发了一个机械模型来剖析突触囊泡融合的动力学，并比较了 DAT-1 的反馈作用与多巴胺自身受体的反馈作用。我们的实验结果和机械模型具有潜在的更广泛意义，因为类似的动力学可能被其他包括跨物种其他神经递质的膜转运蛋白在内的其他突触调节剂所利用。
