组织激肽释放酶对大鼠阴茎海绵体平滑肌cAMP 和cGMP影响的研究

目的探讨组织激肽释放酶对大鼠阴茎海绵体平滑肌cAMP和cGMP的影响，以初步阐明其舒张阴茎海绵体平滑肌的机制。方法采用放射免疫法，测定组织激肽释放酶对培养的大鼠阴茎海绵体平滑肌(去内皮组)和阴茎海绵体平滑肌组织(未去内皮组)cAMP和cGMP的影响，并以硝普钠为阳性对照，以赋形剂为阴性对照。结果100mu组织激肽释放酶使阴茎海绵体平滑肌组织内cAMP和cGMP浓度分别增高2．13倍和2．54倍，而对培养的阴茎海绵体平滑肌cAMP和cGMP没有明显作用。结论组织激肽释放酶能内皮依赖性地提高阴茎海绵体平滑肌细胞内cAMP和cGMP的水平，发挥舒张阴茎海绵体平滑肌的效应。     

乙醇对离体家兔阴茎海绵体的松弛效应及其作用机制

目的:观察乙醇对离体家兔阴茎海绵体的效应并探讨其可能机制。方法:台式生理记录仪测定海绵体张力,放射免疫测定法测定阴茎海绵体cAMP和cGMP含量。结果:①1.25%(V/V)的乙醇能明显增强异丙肾上腺素(10-9～10-5mol/L)对海绵体肌条的舒张效应。②100、300μmol/L的腺苷酸环化酶抑制剂SQ22536能使乙醇(0.25%～3.5%,V/V)对去氧肾上腺素诱导收缩的肌条的舒张曲线右移,100、300μmol/LSQ22536分别使最大舒张效应由(105.12±3.39)%降低到(97.00±2.57)%和(91.09±2.42)%,EC50由(1.18±0.09)%分别增加到(1.36±0.10)%和(1.68±0.13)%(P均<0.05)。③乙醇可浓度依赖性增加家兔阴茎海绵体cAMP含量,而对cGMP含量无影响。④对于提取的兔离体海绵体组织细胞膜碎片上的腺苷酸环化酶,乙醇可浓度依赖性地增强其活性。结论:乙醇可舒张离体家兔海绵体平滑肌,其作用可能是通过cAMP信号转导通路实现的。     

粉防己碱对离体新西兰白兔阴茎海绵体cAMP和cGMP水平的影响

目的探讨粉防己碱(Tet)对离体新西兰白兔阴茎海绵体组织中环磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP)水平的影响,以进一步阐明其舒张阴茎海绵体组织的作用机制。方法采用~(125)I放射免疫测定法,观察Tet对离体新西兰白兔阴茎海绵体组织中cAMP和cGMP水平的影响。结果家兔阴茎海绵体组织中cAMP基础含量为(5.67±0.97)pmol/mg。Tet能直接浓度依赖性地升高阴茎海绵体组织中cAMP的含量(P＜0.05),而腺苷酸环化酶抑制剂(MDL-12,330A)对Tet升高的cAMP水平没有抑制作用(P＞0.05)。对cAMP激发剂前列腺素E_1(PGE_1)诱导产生的阴茎海绵体组织中cAMP水平,Tet也具有浓度依赖性升高作用(P＜0.05)。家兔阴茎海绵体组织中cGMP基础含量为(0.44±0.09)pmol/mg。无论是否存在鸟苷酸环化酶抑制剂(ODQ),Tet对阴茎海绵体组织中cGMP的含量均没有影响(P＞0.05)。对cGMP激发剂硝普钠(SNP)诱导产生的阴茎海绵体组织中cGMP水平,Tet也没有任何影响(P＞0.05)。结论Tet可能是通过抑制磷酸二酯酶活性而增加阴茎海绵体组织中cAMP的含量,这是Tet松弛阴茎海绵体组织的作用机制之一。     

川芎嗪舒张离体兔阴茎海绵体平滑肌的作用及其机制的初步研究

目的 :探讨川芎嗪 (Chuanxiongzine ,Ligustrazine)对离体兔阴茎海绵体平滑肌条的舒张效应及其作用机制。　方法 :采用离体家兔阴茎海绵体肌条张力记录法 ,观察川芎嗪对去氧肾上腺素 (phenylephrine,PE)诱导收缩的阴茎海绵体肌条的舒张作用 ;应用亚硝基左旋精氨酸甲酯 (L NAME)、ODQ预处理和去除内皮 ,分别记录川芎嗪对阴茎海绵体肌的舒张作用。采用放射免疫法测定川芎嗪对阴茎海绵体平滑肌肌条中cGMP和cAMP含量的影响。　结果 :川芎嗪对阴茎海绵体平滑肌具有浓度依赖性舒张作用 ,其EC50 为 1 .5 8× 1 0 -4mol/L ,ODQ可部分抑制川芎嗪对肌条的舒张效应 (P <0 .0 5 ) ,而L NAME预处理和去除内皮对川芎嗪舒张肌条的效应没有影响 (P >0 .0 5 )。川芎嗪处理组阴茎海绵体平滑肌肌条中的cGMP和cAMP含量分别是对照组的 1 .5和 2 .3倍 ,差异有显著性 (P <0 .0 5 )。　结论 :川芎嗪对阴茎海绵体平滑肌具有浓度依赖性的舒张效应 ,其舒张作用机制与增加cGMP、cAMP浓度有关     

不同月龄大鼠阴茎组织中内源性一氧化碳与环磷酸鸟苷和环磷酸腺苷的关系

目的:探讨增龄对大鼠阴茎组织中内源性一氧化碳(CO)与环磷酸鸟苷(cGMP)、环磷酸腺苷(cAMP)含量的变化。方法:8、16、24个月大鼠各8只,分别注射阿朴吗啡(APO)进行大鼠阴茎勃起功能实验;麻醉后取阴茎海绵体,用改良双波长分光光度法测量其CO浓度,并测量其cAPM、cGMP含量。结果:随月龄增加,CO含量降低,各月龄组间差异有显著性(P均<0.01);cGMP、cAMP含量均随月龄增加而逐渐下降,各月龄组间差异有显著性(P均<0.01)。结论:随月龄的增加,大鼠阴茎组织中CO、cAMP、cGMP含量下降,提示衰老对大鼠阴茎组织中CO、cAMP、cGMP含量影响显著。     

内源性一氧化碳对离体犬阴茎海绵体平滑肌的作用

目的:探讨内源性一氧化碳(CO)对离体犬阴茎海绵体平滑肌作用的影响。方法:利用水浴条件下阴茎海绵体肌条的张力测定技术,用CO合成的关键酶血红素氧合酶(HO)的诱导剂———氯高铁血红素诱导海绵体平滑肌生成内源性CO,观察CO对去氧肾上腺素(PE)诱导收缩的阴茎海绵体肌条作用的影响。结果:氯高铁血红素对10μmol/L PE诱导的肌条收缩具有浓度依赖性的松弛作用,10~100μmol/L氯高铁血红素对平滑肌肌条的松弛效应与空白对照相比明显升高(P<0.01)。用锌原卟啉-Ⅸ(ZnPP-Ⅸ)或亚甲蓝孵育处理后的肌条,氯高铁血红素的舒张作用明显减弱(P<0.01)。结论:内源性CO具有浓度依赖性松弛阴茎海绵体平滑肌的作用,其机制可能是通过CO环磷酸鸟苷途径作用所致。     

PDE5基因反义寡脱氧核苷酸对人阴茎海绵体平滑肌细胞cNMP的影响

目的 :观察PDE5基因反义寡脱氧核苷酸对人阴茎海绵体平滑肌细胞内cAMP和cGMP的影响 ,为阴茎勃起功能障碍的基因治疗提供理论和实验依据。　方法 :将PDE5基因反义寡脱氧核苷酸 (含第 1外显子部分序列 )与脂质转染试剂DOTAP共同转染人阴茎海绵体平滑肌原代细胞 ,以酶联免疫法分别检测转染后不同时间 (1～ 4 8h)海绵体平滑肌细胞内cAMP和cGMP的浓度变化 ,观察反义寡脱氧核苷酸对平滑肌细胞内cNMP的影响。　结果 :转染后 ,反义实验组平滑肌原代细胞内cGMP水平 (1～ 6h)显著高于对照组 (P <0 .0 1)。　结论 :PDE5基因反义寡脱氧核苷酸可以增加人阴茎海绵体平滑肌细胞cGMP水平 ,本研究有助于了解PDE5基因与cNMP在阴茎勃起中的作用 ,并为阴茎勃起功能障碍的基因治疗提供理论和实验基础。     

靶向人PDE5A3基因的shRNA对人阴茎海绵体平滑肌细胞cGMP的影响

目的:观察腺病毒载体介导特异性短发夹RNA(shRNA)对人阴茎海绵体平滑肌细胞环磷酸鸟苷(cGMP)的影响,为应用RNA干扰(RNAi)技术治疗阴茎勃起功能障碍(ED)提供实验依据。方法:成功构建携带3条针对人PDE5A3基因位点特异性shRNA的重组腺病毒(rAd5-shRNA-PDE5A3),并设立阴性对照病毒组和空白对照组,分别转染人阴茎海绵体平滑肌细胞。以放射免疫法分别检测转染重组腺病毒24、48、72h后细胞内cGMP浓度变化,观察rAd5-shRNA-PDE5A3对海绵体平滑肌细胞内cGMP的影响。结果:实验组rAd5-shRNA-PDE5A3转染人阴茎海绵体平滑肌细胞后胞内cGMP水平显著高于阴性对照组和空白对照组,在转染后72h最为显著。结论:3条特异性针对人PDE5A3mRNA靶位点的shRNA可有效地增加海绵体平滑肌细胞内cGMP的水平,增强对PDE5基因的阻抑效果。     

阴蒂海绵体中磷酸二酯酶5表达及淫羊藿甙对cGMP浓度的影响

目的　探讨阴蒂海绵体中磷酸二酯酶 5表达及淫羊藿甙对cGMP浓度的影响。　方法　通过反转录聚合酶链反应技术 (RT PCR)检测兔阴蒂海绵体中PDE5mRNA的表达 ;12 5I放射免疫法测定不同浓度淫羊藿甙对阴蒂海绵体内PDE5酶底物cGMP浓度的影响 ,西地那非作为阳性对照 ,分别计算EC50 。　结果　阴蒂海绵体组织中有PDE5的表达 ,淫羊藿甙可明显提高阴蒂海绵体内的cGMP浓度 ,具有显著的浓度依赖性。　结论　淫羊藿甙对阴蒂海绵体平滑肌细胞内cGMP水平的影响可能是通过PDE5发挥作用 ,与NO cGMP信号通路有关。     

PDE5基因siRNA对人阴茎海绵体平滑肌细胞cGMP的影响

目的:观察PDE5基因小干扰RNA(siRNA)对人阴茎海绵体平滑肌细胞环磷酸鸟苷(cGMP)的影响,为阴茎勃起功能障碍(ED)的基因治疗提供实验依据。方法:使用美国Amb ion公司提供的设计软件设计并合成人PDE5基因的siRNA序列,合成3对PDE5 siRNA和1对阴性对照siRNA,转染人阴茎海绵体平滑肌细胞,同时设定空白转染组为对照组。以酶联免疫法分别检测转染后不同时间(24、48、72、96 h)点海绵体平滑肌细胞内cGMP浓度变化,观察PDE5 siRNA对海绵体平滑肌细胞内cGMP的影响。结果:siRNA1、siRNA2和siRNA3转染后人阴茎海绵体平滑肌细胞cGMP水平显著高于阴性对照siRNA组和空白对照组(P<0.05),在转染后72 h最为显著,siRNA1、siRNA2、siRNA3、阴性对照siRNA和空白对照组cGMP测定值分别为:5.89±0.19、3.52±0.16、2.88±0.08、0.72±0.12、0.60±0.16 pmol/m l,siRNA1组明显高于siRNA2、siRNA3组(P<0.05)。结论:体外化学合成的PDE5 siRNA能有效地增加海绵体平滑肌细胞内cGMP的水平,不同序列siRNA增加cGMP水平的能力不同,为ED的基因治疗提供了新思路。     

Effects of plant extract neferine on cyclic adenosine monophosphate and cyclic guanosine monophosphate levels in rabbit corpus cavernosum in vitro

Aim： To further investigate the relaxation mechanism of neferine （NED, a bis-benzylisoquinoline alkaloid extracted （isolated） from the green seed embryo of Nelumbo nucifera Gaertn in China, on rabbit corpus cavernosum tissue in vitro. Methods： The effects of Nef on the concentrations of cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） in isolated and incubated rabbit corpus cavernosum tissue were recorded using ^125I radioimmunoassay. Results： The basal concentration of cAMP in corpus cavernosum tissue was 5.67 ± 0.97 pmol/mg. Nef increased the cAMP concentration in a dose-dependent manner （P 〈 0.05）, but this effect was not inhibited by an adenylate cyclase inhibitor （cis-N-[2-phenylcyclopentyl]azacyclotridec-1-en-2-amine, MDL-12, 330A） （P 〉 0.05）. The accumulation of cAMP induced by prostaglandin Et （PGEt, a stimulator of cAMP production） was also augmented by Nef in a dose-dependent manner （P 〈 0.05）. The basal concentration of cGMP in corpus cavernosum tissue is 0.44 ± 0.09 pmol/mg. Nef did not affect this concentration of cGMP, either in the presence or in the absence of a guanyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ） （P 〉 0.05）. Also, sodium nitroprusside （SNP, a stimulator of cGMP production）-induced cGMP production was not enhanced by Nef （P 〉 0.05）. Conclusion： Nef, with its relaxation mechanism, can enhance the concentration of cAMP in rabbit corpus cavernosum tissue, probably by inhibiting phosphodiesterase activity. （Asian JAndro12008 Mar; 10： 307-312）     

Activation of soluble guanylate cyclase causes relaxation of corpus cavernosum tissue: synergism of nitric oxide and YC-1

Nitric oxide (NO) activates corpus cavernosum smooth muscle soluble guanylate cyclase (sGC) and increases the synthesis of cGMP that results in smooth muscle relaxation and ultimately, penile erection. To characterize sGC and define the potential synergy between NO and the allosteric activator YC-1 in corpus cavernosum, rat sGC was activated by either sodium nitroprusside (SNP) or YC-1, and YC-1 potentiated the effects of SNP with a 200-fold activation of sGC. Both SNP and YC-1 decreased the Km and increased the Vmax. ODQ significantly inhibited sGC activated by SNP with IC50 of 0.5 nM, but did not affect the sGC activated by YC-1 as well as basal sGC activity. SNP and YC-1 synergistically increased intracellular cGMP levels in rabbit corpus cavernosum smooth muscle cell cultures. YC-1 significantly relaxed rabbit cavernosum tissue strips in organ baths with an EC50 of 8.4 microM. In the presence of L-nitroarginine methyl ester to block endogenous NO production, co-administration of SNP shifted the dose response of YC-1 to the left, showing the synergism of SNP and YC-1 in tissue strips. In view of the clinical efficacy of phosphodiesterase-5 inhibitors, activation of sGC may provide an alternative means for enhancing the activity of neurally derived NO during sexual stimulation in the corpus cavernosum, representing a novel approach for the treatment of erectile dysfunction.     

粉防己碱松弛离体新西兰白兔阴茎海绵体作用的研究

目的 :探讨粉防己碱 (Tet)对离体新西兰白兔阴茎海绵体的松弛作用。　方法 :采用离体新西兰白兔阴茎海绵体肌条张力记录法 ,观察Tet对氯化钾 (KCl)和去氧肾上腺素 (PE)诱导收缩的阴茎海绵体肌条的松弛作用 ;L 硝基精氨酸 (L NNA)和亚甲蓝处理后 ,Tet对PE诱导收缩的阴茎海绵体肌条松弛的作用。　结果 :10 μmol/L及3 0 μmol/L的Tet使KCl诱导的最大收缩反应分别降低为 ( 73 .0± 3 .8) %和 ( 41.5± 3 .4) % ,降低程度与Tet的浓度呈正比 (P <0 .0 1)。Tet对 10 μmol/LPE诱导的肌条收缩具有浓度依赖性松弛作用 ,1、10、3 0、10 0 μmol/L的Tet对PE诱导的阴茎海绵体肌条收缩的松弛效应分别为 ( 6.0± 1.4) %、( 2 1.3± 2 .2 ) %、( 47.4± 3 .3 ) %和 ( 68.1±3 .6) % (P <0 .0 1) ;而L NNA及亚甲蓝对Tet的松弛作用没有影响 (P >0 .0 5 )。　结论 :Tet能浓度依耐性地松弛离体新西兰白兔阴茎海绵体 ,其作用机制可能是通过阻滞钙通道 ,而与一氧化氮 环鸟苷酸 (NO cGMP)通路无关     

Relaxation effects of adrenomedullin in isolated rabbit corpus cavernosum smooth muscle

OBJECTIVES: To clarify the pharmacological effects of adrenomedullin, a potent vasodilator and hypotensive peptide isolated from human phaeochromocytoma cells, on corpus cavernosal smooth muscle in vitro, as the intracavernosal injection of adrenomedullin induces penile erection in the anaesthetized cat. MATERIALS AND METHODS: The effects of adrenomedullin were investigated in isolated muscle strips from New Zealand rabbit corpus cavernosum smooth muscle pre-contracted with phenylephrine alone, in the presence of indomethacin (cyclooxygenase inhibitor), Nomega-nitro l-arginine methyl ester (L-NAME, a nitric oxide synthase inhibitor), and K+-channel blockers. RESULTS: Adrenomedullin caused relaxation of isolated pre-contracted rabbit corpus cavernosum strips in a concentration-dependent manner. The response of corpus cavernosum was unaffected L-NAME, indomethacin and K+-channel blockers. CONCLUSION: The relaxation exerted by adrenomedullin in rabbit corporal tissue may arise from the effect of the drug on its specific receptors and/or calcitonin gene-related peptide-1 receptors. The relaxant effect of adrenomedullin might lead to novel clinical applications for erectile dysfunction.     

Misoprostol induces relaxation of human corpus cavernosum smooth muscle: comparison to prostaglandin E1

Prostaglandin E1 (PGE1) relaxes trabecular smooth muscle by interacting with specific G-protein coupled receptors on human corpus cavernosum smooth muscle and increasing intracellular synthesis of cAMP. Misoprostol (Cytotec), is an oral prostaglandin E analogue. The purpose of this study was to compare the functional activity of misoprostol with PGE1 in human corpus cavernosum and cultured human corpus cavernosum smooth muscle cells. Misoprostol, misoprostol free acid or PGE1 induced dose-dependent relaxations in strips of human corpus cavernosum. At concentrations greater than 10(-6) M, tissue recontraction was observed with all three agents. This was abrogated by pretreatment with the thromboxane A2 receptor antagonist SQ29,548. From these observations, we conclude that misoprostol is activated by human corpus cavernosum in situ and relaxes phenylephrine-precontrated tissue strips in vitro. This relaxation response is mediated by the increased cAMP synthesis by these agents.