γ-氨基丁酸及其受体在大鼠颌下腺表达和分布特征

目的：检测γ-氨基丁酸（GABA）及其受体在大鼠颌下腺上皮细胞的表达及分布特征，探讨GABA与腺体合成和分泌功能的关系。方法：用免疫组化EnVision技术，检测GABA、GABA-A和GABA-B受体在SD大鼠颌下腺中的表达，并比较GABA和受体在腺泡和导管系统中的表达强度和细胞分布特征。结果：GABA、γ-氨基丁酸A受体α1亚基（GABA-A α1）、GABA—BR1和GABA-BR2在SD大鼠颌下腺中均有阳性表达。GABA主要分布在颌下腺腺泡和闰管、纹状管和小叶间导管上皮细胞，导管上皮强度大于腺泡上皮，且以纹状管和小叶间导管表达强度更明显，而分布特征比较一致，均位于细胞基底部。GABA-A α1表达于颌下腺小叶间导管、纹状管和部分腺泡上皮；GABA—BR1仅在纹状管上皮有散在表达。结论：大鼠颌下腺腺泡和导管上皮细胞中存在GABA及其受体，GABA系统可能通过GABA受体参与颌下腺分泌和排泄的调控。

Expression and characteristic distribution of gamma-aminobutyric acid and its receptors in submandibular gland of the rat

Objective:To detect the expression of gamma-aminobutyric acid(GABA)and GABA receptors in the epithelial cells of rat submandibular gland. Methods:Immunocytochemical expression of GABA and GABA receptors in submandibular gland of SD rat was investigated by EnVision techniques.Furthermore,the distribution pattern and the functional implications of GABA system were assessed.Results:Immunoreactive GABA was detected in both acinar and ductal cells in the submandibular gland of SD rat.Strong staining for GABA was localized mainly in the cytoplasm near the basement side of epithelial cells of the excretory and striated ducts.GABA-A receptor a1 subunit was positively expressed in the acinar and ductal cells,while GABA-B receptor R1 and R2 subunit was only slight expressed in the epithelial cells of the striated ducts.However,no staining for GABA-A receptor b2 subunit was found in the submandibular gland of SD rat. Conclusion:The expression of GABA and its receptors in the epithelial cells of rat submandibular gland suggests that GABA system might be involved in the secretion and/or excretion of saliva in the rat.