In vitro and in vivo relaxation of corpus cavernosum smooth muscle by the selective myosin II inhibitor, blebbistatin.
In vitro and in vivo relaxation of corpus cavernosum smooth muscle by the selective myosin II inhibitor, blebbistatin.
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DOI：
10.1111/j.1743-6109.2009.01424.x
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
Xinhua Zhang;Memduha Aydin;Dwaraka Kuppam;A. Melman;M. DiSanto
中科院分区：
文献类型：
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作者：
Xinhua Zhang;Memduha Aydin;Dwaraka Kuppam;A. Melman;M. DiSanto
Blebbistatin （BLEB）是一种小细胞可渗透分子，最初被报道为横纹肌和非肌肉细胞（IC(50) = 0.5-5微米）表达的肌球蛋白II亚型的选择性抑制剂，对火鸡砂囊平滑肌（SM）肌球蛋白II （IC（50）约80微米）的抑制作用较差。然而，最近发现BLEB可以有效抑制哺乳动物动脉SM （IC（50）约5微米）。目的探讨BLEB对海绵体SM （CCSM）张力和勃起功能的影响。方法采用阴茎植入患者的CC组织与成年雄性大鼠的CC组织、主动脉和膀胱进行BLEB器官浴研究。给予大鼠海绵体内BLEB，并通过海绵体内压力（ICP）评估EF。主要观察指标：BLEB对激动剂诱导的CCSM、主动脉和膀胱收缩的体外及体内ICP的影响。结果BLEB以剂量依赖性方式完全放松人CCSM预收缩的苯肾上腺素（PE），在10微米时张力降低76.5%。BLEB预孵育可将pe诱导的人CC收缩减弱约85%。内皮素-1或KCl预收缩的人CC条几乎完全被BLEB松弛。PE预收缩的大鼠CCSM表现出与人类CCSM相当的BLEB松弛。BLEB对大鼠主动脉的抑制作用相似，但对膀胱的抑制作用较慢。最大颅内压和颅内压/平均动脉压均在1微摩尔完全勃起的海绵内注射BLEB后呈剂量依赖性升高。结论：我们的新数据表明，BLEB几乎完全放松大鼠和人类CCSM预先收缩的各种强效激动剂，并表现出组织选择性。结合我们的体内数据，纳米剂量的BLEB显著增加ICP，我们的数据证实了SM收缩装置在EF的分子机制中的重要作用，并表明BLEB结合肌球蛋白II的可能性，通过靶向SM收缩途径作为ED的治疗方法。
INTRODUCTION Blebbistatin (BLEB) is a small cell permeable molecule originally reported as a selective inhibitor of myosin II isoforms expressed by striated muscle and non-muscle cells (IC(50) = 0.5-5 microM) with poor inhibition of turkey gizzard smooth muscle (SM) myosin II (IC(50) approximately 80 microM). However, recently it was found that BLEB can potently inhibit mammalian arterial SM (IC(50) approximately 5 microM). AIM To investigate the effect of BLEB on corpus cavernosum SM (CCSM) tone and erectile function (EF). METHODS CC tissue obtained from penile implant patients along with CC, aorta and bladder from adult male rats were used for BLEB organ bath studies. Intracavernosal BLEB was administered to rats and EF was assessed via intracavernous pressure (ICP). MAIN OUTCOME MEASURES Effects of BLEB on agonist-induced CCSM, aorta and bladder contraction in vitro and ICP in vivo. RESULTS BLEB completely relaxed human CCSM pre-contracted with phenylephrine (PE) in a dose-dependent manner decreasing tension by 76.5% at 10 microM. BLEB pre-incubation attenuated PE-induced contraction of human CC by approximately 85%. Human CC strips pre-contracted with endothelin-1 or KCl were almost completely relaxed by BLEB. Rat CCSM pre-contracted with PE showed BLEB relaxation comparable to human CCSM. BLEB inhibition was similar for rat aorta but slower for bladder. Both maximal ICP and ICP/mean arterial pressure were dose-dependently increased by BLEB intracavernous injections with full erection at 1 micromole. CONCLUSION Our novel data reveals that BLEB nearly completely relaxes rat and human CCSM pre-contracted with a variety of potent agonists and exhibits tissue selectivity. Coupled with our in vivo data in which nanomole doses of BLEB significantly increase ICP, our data substantiates an important role for the SM contractile apparatus in the molecular mechanism for EF and suggests the possibility of BLEB binding at myosin II as a therapeutic treatment for ED by targeting SM contractile pathways.