中文摘要：

目的研究α-肾上腺素受体亚型在家兔颌下腺的表达和分布，及其激动剂——苯肾上腺素促家兔颌下腺唾液分泌的相关机制。方法应用RT—PCR和Western blot检测家兔正常颌下腺α1-肾上腺素受体亚型mRNA及蛋白质的表达；免疫组化法检测颌下腺α1-肾上腺素受体亚型的分布及水通道蛋白5的表达；经颌下腺导管插管给予（1×10^-8）-（1×10^-6）moL／L的苯肾上腺素，观察家兔心率和血压的变化及促颌下腺唾液分泌的量效关系。结果家兔颌下腺有α1A-α1B和α1D-肾上腺素受体3种亚型的mRNA及蛋白质的表达，并广泛分布于导管和腺泡细胞的胞膜及胞质中。给予1×10^-7moL／L苯肾上腺素7d，促进颌下腺唾液分泌增加，而对心率、血压无明显影响；水通道蛋白5在腺泡及导管细胞的顶膜和侧膜的表达增加。结论家兔颌下腺存在α1A-、α1B-和α1D-肾上腺素受体3种亚型的mRNA和蛋白质的表达。经颌下腺导管给予低剂量苯肾上腺素促进唾液分泌是安全有效的；水通道蛋白5的表达增加可能与苯肾上腺素促唾液分泌的机制有关，该研究为临床治疗领下腺功能低下提供了初步依据。

英文摘要：

Objective To investigate the expression and distribution of α1 -adrenoceptor subtypes in rabbit submandibular gland and the effect of phenylephrine on salivary secretion. Methods The expressions of α1A-, α1B-, and α1D-adrenoceptor mRNA and protein were investigated by reverse transcription- polymerase chain reaction （ RT-PCR ） and Western blot in rabbit submandibular gland. Immunohistochemical assay was applied to detect the distribution of α1A-, α1B-, and α1D-adrenoceptor and localization of aquaporin 5 in rabbit submandibular gland. Different concentrations of phenylephrine （ 1 × 10^-8）-（ 1 × 10^-6） mol/L were administrated through a polyethylene tube, which was intubated into Wharton＇s duct of submandibular gland. Heart rate and blood pressure of rabbits were observed during phenylephrine administration. Salivary flow was measured by the length of moist filter paper （ 35 mm × 5 mm） within 5 min. Results α1A-, α1B-, and α1D- adrenoceptor mRNA and protein were expressed in rabbit submandibular gland. Three α1-adrenoceptor subtypes were widely distributed in the membrane and cytoplasma of both acinar and ductal cells. Phenylephrine （ 1 × 10^-7 mol/L, 100 μl） stimulated effectively salivary secretion without inducing significant alteration of blood pressure and heart rate in rabbit. assay showed that aquaporin 5 was mainly localized in the apical and lateral plasma membrane in both acinar and ductal cells in unstimulated condition, while the expression of aquaporin 5 was increased after administration of phenylephrine. Conclusions Expression of α1A-, α1B-, and α1D- adrenoceptor mRNA and protein was existed in rabbit submandibular gland. Phenylephrine safely and effectively promoted salivary secretion when it was administrated through Wharton＇s duct of submandibular gland. The mechanism of phenylephrine on salivary secretion may involve in the increase of expression of aquaporin 5 in the apical and lateral plasma membrane in rabbit submandibular gland. This study will hope