Department of Urology, University of Munich, Munich, Germany.
BJU Int. 2011 Sep;108(6):922-8. doi: 10.1111/j.1464-410X.2010.10021.x. Epub 2011 Mar 4.
• To test whether β1-adrenoceptor activation leads to phosphorylation of the β2-adrenoceptor in human prostate tissue.
• Prostate tissue from patients undergoing radical prostatectomy was stimulated in vitro with the α1-adrenergic agonist phenylephrine (10 µM). • α2-adrenoceptor phosphorylation at serines 345/346 was studied using Western blot analysis with a phospho-specific antibody. • The role of second messenger kinases was assessed by studying the effects of the protein kinase C (PKC) inhibitor Ro 31-8425 and the protein kinase A (PKA) inhibitor H89 on phenylephrine-induced phosphorylation. • The expression of G protein-coupled receptor kinases (GRKs) 2/3 was analysed using quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR), Western blot analysis and immunohistochemistry.
• Stimulation of prostate tissue with phenylephrine resulted in phosphorylation of the β2-adrenoceptor (5, 10 and 20 min after stimulation). • This α1-adrenoceptor-induced phosphorylation of β2-adrenoceptors was resistant to inhibition of PKC and PKA. • Changes in phosphorylation levels were not attributable to changes in receptor levels, as these remained constant during stimulation. • RT-PCR and Western blot analysis showed expression of GRK2/3 in human prostate tissues. • Immunohistochemical staining showed that GRK2/3 expression in human prostate tissue is located to stromal and smooth muscle cells.
• Activation of α1-adrenoceptors causes phosphorylation of β2-adrenoceptors in the human prostate. This may enhance α1-adrenergic contraction and is possibly mediated by GRK2, which is expressed in prostate smooth muscle. • Mutual regulation between different adrenergic receptors might be involved in the therapeutic effects of α1-blockers in patients with benign prostate hyperplasia.
• 检测β1-肾上腺素受体激活是否会导致人前列腺组织中β2-肾上腺素受体的磷酸化。
• 对接受根治性前列腺切除术的患者的前列腺组织进行体外刺激，使用α1-肾上腺素能激动剂苯肾上腺素（10 μM）。• 使用磷酸化特异性抗体通过 Western blot 分析研究α2-肾上腺素受体丝氨酸 345/346 的磷酸化。• 通过研究蛋白激酶 C（PKC）抑制剂 Ro 31-8425 和蛋白激酶 A（PKA）抑制剂 H89 对苯肾上腺素诱导的磷酸化的影响来评估第二信使激酶的作用。• 使用定量逆转录聚合酶链反应（RT-PCR）、Western blot 分析和免疫组织化学分析来分析 G 蛋白偶联受体激酶（GRK）2/3 的表达。
• 用苯肾上腺素刺激前列腺组织可导致β2-肾上腺素受体磷酸化（刺激后 5、10 和 20 分钟）。• 这种由α1-肾上腺素受体引起的β2-肾上腺素受体磷酸化对 PKC 和 PKA 的抑制具有抗性。• 磷酸化水平的变化与受体水平的变化无关，因为在刺激过程中受体水平保持不变。• RT-PCR 和 Western blot 分析显示 GRK2/3 在人前列腺组织中的表达。• 免疫组织化学染色显示 GRK2/3 在人前列腺组织中的表达位于基质和平滑肌细胞。
• 激活α1-肾上腺素受体可导致人前列腺中β2-肾上腺素受体的磷酸化。这可能增强α1-肾上腺素能收缩，可能是由在前列腺平滑肌中表达的 GRK2 介导的。• 不同肾上腺素能受体之间的相互调节可能涉及α1-阻滞剂在良性前列腺增生患者中的治疗效果。
