Tomás J, Santos C R A, Quintela T, Gonçalves I
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal.
CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal.
Neuroscience. 2016 Apr 21;320:160-71. doi: 10.1016/j.neuroscience.2016.01.057. Epub 2016 Feb 2.
The choroid plexus (CP) located in brain ventricles, by forming the interface between the blood and the cerebrospinal fluid (CSF) is in a privileged position to monitor the composition of these body fluids. Yet, the mechanisms involved in this surveillance system remain to be identified. The taste transduction pathway senses some types of molecules, thereby evaluating the chemical content of fluids, not only in the oral cavity but also in other tissues throughout the body, such as some cell types of the airways, the gastrointestinal tract, testis and skin. Therefore, we hypothesized that the taste transduction pathway could also be operating in the CP to assess the composition of the CSF. We found transcripts for some taste receptors (Tas1r1, Tas1r2, Tas1r3, Tas2r109 and Tas2r144) and for downstream signaling molecules (α-Gustducin, Plcβ2, ItpR3 and TrpM5) that encode this pathway, and confirmed the expression of the corresponding proteins in Wistar rat CP explants and in the CP epithelial cells (CPEC). The functionality of the T2R receptor expressed in CP cells was assessed by calcium imaging, of CPEC stimulated with the bitter compound D-Salicin, which elicited a rise in the intracellular Ca(2+). This effect was diminished in the presence of the bitter receptor blocker Probenecid. In summary, we described the expression of the taste-related components involved in the transduction signaling cascade in CP. Taken together, our results suggest that the taste transduction pathway in CPEC makes use of T2R receptors in the chemical surveillance of the CSF composition, in particular to sense bitter noxious compounds.
脉络丛（CP）位于脑室，通过形成血液与脑脊液（CSF）之间的界面，处于监测这些体液成分的特殊位置。然而，这个监测系统所涉及的机制仍有待确定。味觉转导途径能感知某些类型的分子，从而评估体液的化学成分，不仅在口腔，还在身体的其他组织中，如气道、胃肠道、睾丸和皮肤的一些细胞类型。因此，我们推测味觉转导途径也可能在脉络丛中发挥作用，以评估脑脊液的成分。我们发现了一些编码该途径的味觉受体（Tas1r1、Tas1r2、Tas1r3、Tas2r109和Tas2r144）以及下游信号分子（α - 味导素、磷脂酶Cβ2、肌醇三磷酸受体3和瞬时受体电位通道蛋白M5）的转录本，并在Wistar大鼠脉络丛外植体和脉络丛上皮细胞（CPEC）中证实了相应蛋白质的表达。通过钙成像评估了脉络丛细胞中表达的T2R受体的功能，用苦味化合物D - 水杨苷刺激CPEC，可引起细胞内Ca(2+)升高。在存在苦味受体阻滞剂丙磺舒的情况下，这种效应减弱。总之，我们描述了脉络丛中参与转导信号级联的味觉相关成分的表达。综上所述，我们的结果表明，脉络丛上皮细胞中的味觉转导途径利用T2R受体对脑脊液成分进行化学监测，特别是感知苦味有害化合物。
