Department of Physiology, Shandong University School of Medicine, and Department of Obstetrics and Gynecology, Qilu Hospital of Shandong University, Jinan 250012, China.
Biochem Biophys Res Commun. 2010 Jul 23;398(2):237-41. doi: 10.1016/j.bbrc.2010.06.066. Epub 2010 Jun 19.
Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system and exerts its actions via ionotropic (GABAA and GABAC) and metabotropic (GABAB) receptors. The GABAB receptor is a dimer composed of R1 and R2 components. In addition to their location on neurons, GABA and functional GABAB receptors also have been detected in some peripheral tissues. In the present study, we combined immunohistochemistry, immunoblot and tension recording to determine if the human fallopian tube express glutamic acid decarboxylase (GAD65/67), two isoforms for synthesis of GABA and functional GABAB receptors. Immunoblots showed that the human fallopian tube tissue contained GABABR1 protein which was localized in the epithelial cells and smooth muscle cells by immunohistochemistry. In addition, epithelial cells also expressed GAD65/67. Tension recording found that both GABA and baclofen, a GABAB receptor agonist increased the spontaneous activity of human fallopian tube. The expressions of GABABR and GAD65/67 were significantly upregulated in the ectopic pregnancy group than in the intrauterine pregnancy group. We conclude that the human fallopian tube is capable of synthesizing GABA and expresses functionally active GABAB receptors. An upregulation of GABA synthesis and corresponding GABAB receptors may involve in ectopic pregnancy.
γ-氨基丁酸（GABA）是哺乳动物中枢神经系统中的主要抑制性神经递质，通过离子型（GABAA 和 GABAC）和代谢型（GABAB）受体发挥作用。GABAB 受体是由 R1 和 R2 组成的二聚体。除了位于神经元上，GABA 和功能性 GABAB 受体也在一些外周组织中被检测到。在本研究中，我们结合免疫组织化学、免疫印迹和张力记录来确定人类输卵管是否表达谷氨酸脱羧酶（GAD65/67），这是 GABA 合成的两种同工型和功能性 GABAB 受体。免疫印迹显示，人类输卵管组织含有 GABABR1 蛋白，其通过免疫组织化学定位于上皮细胞和平滑肌细胞。此外，上皮细胞还表达 GAD65/67。张力记录发现 GABA 和巴氯芬（GABAB 受体激动剂）均增加了人输卵管的自发活动。与宫内妊娠组相比，异位妊娠组的 GABABR 和 GAD65/67 的表达显著上调。我们得出结论，人输卵管能够合成 GABA 并表达功能活跃的 GABAB 受体。GABA 合成和相应的 GABAB 受体的上调可能与异位妊娠有关。
