Corbani Maithé, Marir Rafik, Trueba Miguel, Chafai Magda, Vincent Anne, Borie Amélie M, Desarménien Michel G, Ueta Yoichi, Tomboly Csaba, Olma Aleksandra, Manning Maurice, Guillon Gilles
Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of Montpellier, 141 rue de la Cardonille, 34094 cedex 05, France.
Institute of Functional Genomics, CNRS UMR5203, INSERM U661, University of Montpellier, 141 rue de la Cardonille, 34094 cedex 05, France.
Gen Comp Endocrinol. 2018 Mar 1;258:15-32. doi: 10.1016/j.ygcen.2017.10.011. Epub 2017 Nov 17.
It is now accepted that vasopressin, through V/V receptors, centrally regulates cognitive functions such as memory, affiliation, stress, fear and depression. However, the respective roles of these receptor isoforms and their contribution to stress-related pathologies remain uncertain. The development of new therapeutic treatments requires a precise knowledge of the distribution of these receptors within the brain, which has been so far hampered by the lack of selective V markers. In the present study, we have determined the pharmacological properties of three new potent rat V fluorescent ligands and demonstrated that they constitute valuable tools for simultaneous visualization and activation of native V receptors in living rat brain tissue. Thus, d[Leu,Lys-Alexa 647)]VP (analogue 3), the compound with the best affinity-selectivity/fluorescence ratio for the V receptor emerged as the most promising. The rat brain regions most concerned by stress such as hippocampus, olfactory bulbs, cortex and amygdala display the highest V fluorescent labelling with analogue 3. In the hippocampus CA, V receptors are located on glutamatergic, not GABAergic neurones, and are absent from astrocytes. Using AVP-EGFP rats, we demonstrate the presence of V autoreceptors on AVP-secreting neurones not only in the hypothalamus, but also sparsely in the hippocampus. Finally, using both electrophysiology and visualization of ERK phosphorylation, we show analogue 3-induced activation of the V receptor in situ. This will help to analyse expression and functionality of V receptors in the brain and contribute to further explore the AVPergic circuitry in normal and pathological conditions.
目前已公认，血管加压素通过V/V受体在中枢调节认知功能，如记忆、情感、应激、恐惧和抑郁。然而，这些受体亚型各自的作用及其对应激相关病理的贡献仍不明确。新治疗方法的开发需要精确了解这些受体在脑内的分布情况，而迄今为止，由于缺乏选择性V标记物，这一研究受到了阻碍。在本研究中，我们确定了三种新型强效大鼠V荧光配体的药理学特性，并证明它们是在活体大鼠脑组织中同时可视化和激活天然V受体的有价值工具。因此，d[Leu,Lys-Alexa 647)]VP（类似物3），这种对V受体具有最佳亲和力-选择性/荧光比的化合物，成为了最有前景的工具。大鼠脑中与应激最相关的区域，如海马体、嗅球、皮层和杏仁核，用类似物3显示出最高的V荧光标记。在海马体CA区，V受体位于谷氨酸能神经元而非GABA能神经元上且星形胶质细胞中不存在。利用AVP-EGFP大鼠，我们证明不仅在下丘脑，而且在海马体中稀疏分布的AVP分泌神经元上也存在V自身受体。最后，通过电生理学和ERK磷酸化的可视化，我们展示了类似物3在原位诱导的V受体激活。这将有助于分析脑内V受体的表达和功能，并有助于进一步探索正常和病理条件下的AVP能神经回路。
