Neuroanatomical distribution and function of the vasopressin V-1B receptor in the rat brain deciphered using specific fluorescent ligands

作者：Corbani Maithe; Marir Rafik; Trueba Miguel; Chafai Magda; Vincent Anne; Borie Amelie M; Desarmenien Michel G; Ueta Yoichi; Tomboly Csaba; Olma Aleksandra; Manning Maurice; Guillon Gilles

来源：General and Comparative Endocrinology, 2018, 258: 15-32.

DOI：10.1016/j.ygcen.2017.10.011

• Vasopressin receptors
• V-1B brain anatomy
• Central nervous system
• Rodents
• GPCR
• Stress
• Anxiety

It is now accepted that vasopressin, through V-1A/V-1B 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-1B markers. In the present study, we have determined the pharmacological properties of three new potent rat V-1B fluorescent ligands and demonstrated that they constitute valuable tools for simultaneous visualization and activation of native V-1B receptors in living rat brain tissue. Thus, d[Leu(4),Lys-Alexa 647)(8)]VP (analogue 3), the compound with the best affinity-selectivity/fluorescence ratio for the V-1B 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-1B fluorescent labelling with analogue 3. In the hippocampus CA(2), V-1B receptors are located on glutamatergic, not GABAergic neurones, and are absent from astrocytes. Using AVP-EGFP rats, we demonstrate the presence of V-1B 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-1B receptor in situ. This will help to analyse expression and functionality of V-1B receptors in the brain and contribute to further explore the AVPergic circuitry in normal and pathological conditions.

• 出版日期2018-3-1