肾上腺素β受体在大鼠逼尿肌中的表达及功能

EXPRESSION AND FUNCTION OF THE β-ADRENOCEPTORS IN RAT DETRUSOR MUSCLE

为研究β肾上腺素能受体 (β AR)亚型在大鼠膀胱逼尿肌中的表达及介导逼尿肌舒张功能的情况 ,采用离体逼尿肌条拉力实验观察β AR亚型特异性激动剂和拮抗剂对逼尿肌舒张功能的影响 ,以RT PCR方法观察逼尿肌β受体亚型的分布。结果发现 ,选择性β1、β2 、β3 AR激动剂T 0 5 0 9、沙丁胺醇与BRL37344A均呈浓度依赖性地抑制KCl诱导的逼尿肌条收缩 ;低浓度β3 AR拮抗剂和较高浓度的β1、β2 AR拮抗剂能抑制异丙肾上腺素的舒张作用 ;采用RT PCR在大鼠逼尿肌可以检测到β1、β2 、β3 ARmRNA表达 ,其中β3 ARmRNA的密度约占总β AR密度的 70 %。提示大鼠膀胱逼尿肌上有β1、β2 、β3 AR三种亚型存在 ,可介导大鼠逼尿肌舒张 ,其中β3

To investigate the expression of β adrenoceptors(β AR) and its possible function in rat detrusor. The relaxation response produced by β AR subtypes(β 1 , β 2 , β 3 AR) agonists or antagonists were examined by means of the in vitro detrusor strip study, and the expression of β AR subtypes mRNA was investigated in rat detrusor muscle by RT PCR. The selective β 1 agonist T 0509, β 2 agonist salbutamol, β 3 agonist BRL37344A depressed the contractions of the detrusor muscle induced by KCl. The relaxant response to isoproterenol was antagonized by the β 1 ,β 2 AR antagonists(100μmol/L) and the β 3 AR antagonists SR59230(1μmol/L).RT PCR, showing that all three subtypes of β AR subtypes mRNA were expressed in rat detrusor smooth muscles, in which β 3 AR mRNA occupied 70%. All the β 1 ,β 2 ,β 3 adrenoceptors participate in mediating relaxation of rat detrusor, among them β 3 AR is the main one.