Horinouchi Takahiro, Tanaka Yoshio, Koike Katsuo
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
Eur J Pharmacol. 2003 Jul 18;473(1):79-82. doi: 10.1016/s0014-2999(03)01943-5.
beta-Adrenoceptor subtypes mediating relaxation were examined by using pharmacological and molecular analyses in guinea-pig esophageal muscularis mucosae. (-)-Isoprenaline-induced relaxations were antagonized by (+/-)-propranolol (pA2 = 8.47+/-0.07), a selective beta1-adrenoceptor antagonist, (+/-)-2-hydroxy-5-[2-[[2-hydroxy-3-[4-[1-methyl-4-(trifluoromethyl)-1H-imidazol-2-yl]phenoxy]propyl]amino]ethoxy]-benzamide methanesulfonate (CGP20712A; pA(2)=9.43+/-0.09), and a selective beta(2)-adrenoceptor antagonist, (+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride (ICI-118,5511; pA2 = 7.11+/-0.04), indicating that beta(1)-adrenoceptors but not beta2- or beta3-adrenoceptors were essentially involved in beta-adrenoceptor-mediated relaxations. However, the expression of messenger RNA (mRNA) for beta1- and beta2-adrenoceptors, but not for beta3-adrenoceptors, was detected by reverse transcription-polymerase chain reaction (RT-PCR). These results clearly suggest that not all beta-adrenoceptor mRNA expressed strictly reflect functional receptors in guinea-pig esophageal muscularis mucosae.
通过药理学和分子分析方法，在豚鼠食管肌层黏膜中研究介导舒张作用的β-肾上腺素能受体亚型。（-）-异丙肾上腺素诱导的舒张作用被选择性β1-肾上腺素能受体拮抗剂（±）-普萘洛尔（pA2 = 8.47±0.07）、（±）-2-羟基-5-[2-[[2-羟基-3-[4-[1-甲基-4-（三氟甲基）-1H-咪唑-2-基]苯氧基]丙基]氨基]乙氧基]-苯甲酰胺甲磺酸盐（CGP20712A；pA2 = 9.43±0.09）以及选择性β2-肾上腺素能受体拮抗剂（±）-1-[2,3-（二氢-7-甲基-1H-茚-4-基）氧基]-3-[(1-甲基乙基)氨基]-2-丁醇盐酸盐（ICI-118,5511；pA2 = 7.11±0.04）拮抗，这表明β-肾上腺素能受体介导的舒张作用主要涉及β1-肾上腺素能受体，而非β2-或β3-肾上腺素能受体。然而，通过逆转录-聚合酶链反应（RT-PCR）检测到β1-和β2-肾上腺素能受体的信使核糖核酸（mRNA）表达，但未检测到β3-肾上腺素能受体的mRNA表达。这些结果清楚地表明，在豚鼠食管肌层黏膜中，并非所有表达的β-肾上腺素能受体mRNA都严格反映功能性受体。
