OBJECTIVE Mice and rats are important animal models for mast cell (MC) study. However, rat Mas-related-GPCR-B3 receptor (MRGPRB3) has been less studied than its mouse counterpart. Therefore, we aimed to characterize rat MRGPRB3. METHODS Mrgprb3 mRNA expression was assessed in peritoneal cells (RPCs) and peritoneal MCs (RPMCs) of wild-type rats, RPCs of MC-deficient rats, and RBL-2H3 cells by reverse-transcriptase polymerase chain reaction (RT-PCR). RPMCs, MRGPRX2-transfected and non-transfected RBL-2H3 cells were activated by 15-30 min incubation with DNP-BSA, substance-P (SP), or compound-48/80. L732138 or CP96344 was used as a tachykinin/neurokinin-1-receptor antagonist. Histamine release from MCs was measured by HPLC fluorometry. RESULTS Mrgprb3 mRNA expression was found in all cells, with the highest level in wild-type RPCs. All cells responded to DNP-BSA, but only MRGPRX2-transfected-RBL-2H3 cells and RPMCs responded to all activators. L732138 (0.1-10 μM) and CP96344 (1-100 μM) suppressed SP (10 μM)-induced RPMC activation. L732138 inhibition was dose independent, whereas CP96344 inhibition occurred in a dose-dependent manner. Additionally, only CP96344 suppressed SP (100 μM)- and compound-48/80 (10 μg/mL)-induced RPMC activation. CONCLUSIONS RPMCs expressing functional MRGPRB3 response upon MRGPRX2 ligands to regulated MC-mediated activities. It`s provide novel insights for future pseudo-allergic studies in rodents.

中文翻译：

---

Tachykinin-1受体拮抗作用抑制了表达功能性mas相关GPCR B3的大鼠肥大细胞对物质P和化合物48/80诱导的肥大细胞活化。

目的小鼠和大鼠是进行肥大细胞（MC）研究的重要动物模型。但是，与小鼠Mas相关的GPCR-B3受体（MRGPRB3）的研究较少。因此，我们旨在表征大鼠MRGPRB3。方法通过逆转录聚合酶链反应（RT-PCR）检测野生型大鼠腹膜细胞（RPCs）和腹膜MCs（RPMCs），MC缺陷型大鼠RPCs和RBL-2H3细胞中Mrgprb3 mRNA的表达。通过与DNP-BSA，物质-P（SP）或化合物-48/80孵育15-30分钟来激活RPMC，MRGPRX2转染的和未转染的RBL-2H3细胞。L732138或CP96344用作速激肽/神经激肽-1-受体拮抗剂。通过HPLC荧光法测量从MC中释放的组胺。结果在所有细胞中均发现了Mrgprb3 mRNA表达，在野生型RPC中含量最高。所有细胞均对DNP-BSA产生反应，但只有MRGPRX2转染的RBL-2H3细胞和RPMC对所有激活剂均产生反应。L732138（0.1-10μM）和CP96344（1-100μM）抑制了SP（10μM）诱导的RPMC活化。L732138抑制是剂量无关的，而CP96344抑制是以剂量依赖性的方式发生的。此外，仅CP96344抑制了SP（100μM）和化合物-48/80（10μg/ mL）诱导的RPMC活化。结论RPMCs表达功能性MRGPRB3响应MRGPRX2配体对调控的MC介导的活性。它为将来在啮齿动物中的伪过敏研究提供了新颖的见解。而CP96344抑制则以剂量依赖性方式发生。此外，仅CP96344抑制了SP（100μM）和化合物-48/80（10μg/ mL）诱导的RPMC活化。结论RPMCs表达功能性MRGPRB3响应MRGPRX2配体对调控的MC介导的活性。它为今后在啮齿动物中的伪过敏研究提供了新颖的见解。而CP96344抑制则以剂量依赖性方式发生。此外，仅CP96344抑制了SP（100μM）和化合物-48/80（10μg/ mL）诱导的RPMC活化。结论RPMCs表达功能性MRGPRB3响应MRGPRX2配体对调控的MC介导的活性。它为将来在啮齿动物中的伪过敏研究提供了新颖的见解。