Activation of proteinase-activated receptor-1 inhibits neurally evoked chloride secretion in the mouse colon in vitro
Activation of proteinase-activated receptor-1 inhibits neurally evoked chloride secretion in the mouse colon in vitro
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DOI：
10.1152/ajpgi.00112.2004
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发表时间：
2005-02-01
影响因子：
4.5
通讯作者：
MacNaughton, WK
中科院分区：
文献类型：
--
作者：
Buresi, MC;Vergnolle, N;MacNaughton, WK
蛋白酶激活的凝血酶受体-1（PAR-1）属于一个独特的G蛋白偶联受体家族，通过蛋白水解裂解激活。我们研究了PAR-1激活在离体小鼠结肠离子转运调节中的作用。采用RT-PCR和免疫组织化学方法检测PAR-1在小鼠结肠中的表达。为了研究PAR-1活化在氯化物分泌中的作用，将小鼠结肠固定在Ussing室中。在电场刺激（EFS）之前，在暴露于凝血酶、盐水、PAR-1激活肽TFLLR-NH 2或无活性反向肽RLLFT-NH 2的组织中测量短路电流（I-sc）的变化。在PAR-1拮抗剂存在下或在PAR-1缺陷小鼠中重复实验以评估受体特异性。此外，在无氯缓冲液或毒蕈碱拮抗剂阿托品存在下进行研究，以评估氯依赖性和胆碱能神经元在PAR-1诱导效应中的作用。PAR-1 mRNA在小鼠结肠全层标本和粘膜刮片中均有表达。PAR-1在粘膜下神经节的上皮细胞和神经元上呈阳性反应，与VIP和神经肽Y共定位。凝血酶或TFLLR-NH 2激活PAR-1后，分泌反应EFS，但不是那些毛喉素或卡巴胆碱显着减少。在PAR-1拮抗剂的存在下，在PAR-1缺陷小鼠中，当氯化物从洗浴介质中排除时，或当阿托品存在时，未观察到对EFS的反应降低。PAR-1在小鼠结肠粘膜下神经节中表达，其激活导致神经诱发的上皮氯分泌减少。
The proteinase-activated thrombin receptor-1 (PAR-1) belongs to a unique family of G protein-coupled receptors activated by proteolytic cleavage. We studied the effect of PAR-1 activation in the regulation of ion transport in mouse colon in vitro. Expression of PAR-1 in mouse colon was assessed by RT-PCR and immunohistochemistry. To study the role of PAR-1 activation in chloride secretion, mouse colon was mounted in Ussing chambers. Changes in short-circuit current (I-sc) were measured in tissues exposed to either thrombin, saline, the PAR-1-activating peptide TFLLR-NH2, or the inactive reverse peptide RLLFT-NH2, before electrical field stimulation (EFS). Experiments were repeated in the presence of either a PAR-1 antagonist or in PAR-1-deficient mice to assess receptor specificity. In addition, studies were conducted in the presence of chloride-free buffer or the muscarinic antagonist atropine to assess chloride dependency and the role of cholinergic neurons in the PAR-1-induced effect. PAR-1 mRNA was expressed in full-thickness specimens and mucosal scrapings of mouse colon. PAR-1 immunoreactivity was found on epithelial cells and on neurons in submucosal ganglia where it was colocalized with both VIP and neuropeptide Y. After PAR-1 activation by thrombin or TFLLR-NH2, secretory responses to EFS but not those to forskolin or carbachol were significantly reduced. The reduction in the response to EFS was not observed in the presence of the PAR-1 antagonist, in PAR-1-deficient mice, when chloride was excluded from the bathing medium, or when atropine was present. PAR-1 is expressed in submucosal ganglia in the mouse colon and its activation leads to a decrease in neurally evoked epithelial chloride secretion.