In vitro evaluation of nebivolol effects on nonadrenergic noncholinergic responses in rabbit corpus cavernosum

The purpose of this study was to compare the effects of nebivolol on nonadrenergic noncholinergic (NANC) relaxation functions that are mediated by electric field stimulation (EFS) in rabbit corpus cavernosum smooth muscle by comparison with other beta‐adrenergic receptor blockers and show the level on which its effects through nitric oxide take place. After the effects of nebivolol on the isolated corpus cavernosum tissues that were contracted through the alpha‐adrenergic pathway and application of L‐NAME’ (N^G‐nitro‐L‐arginine methyl ester) which is a competitive inhibitor of nitric oxide synthase (NOS), the changes that occurred were recorded. Following the effect on the tissue that was contracted with phenylephrine in the presence of atropine and guanethidine that was created by EFS, nebivolol and other beta‐blockers were added and the changes were recorded. After receiving relaxation responses with EFS‐mediated NANC, no difference was observed between the relaxation responses due to addition of nebivolol and other beta‐adrenergic blockers (p > 0.05). The finding that nebivolol which has a NO‐mediated relaxation effect did not have an effect on EFS‐mediated NANC relaxation but created relaxation on the tissue that was contracted by phenylephrine and the effect was reversed by L‐NAME, shows that its effects are on a postsynaptic level.     

Penicillamine administration reverses the inhibitory effect of hyperhomocysteinaemia on endothelium-dependent relaxation in the corpus cavernosum in the rabbit

OBJECTIVE: To elucidate the role of copper in mediating the impact of homocysteine on vasculogenic erectile dysfunction (VED), by investigating the effect of dietary supplementation with the copper-chelator penicillamine to rabbits rendered hyperhomocysteinaemic (HHC) with a methionine-rich diet, as a raised plasma level of homocysteine might be a risk factor for VED. MATERIALS AND METHODS: Homocysteine inhibits the nitric oxide (NO)-dependent relaxation of the corpus cavernosum (CC), an effect which appears to be mediated via the generation of superoxide (O2*-), and H2O2. Copper is a catalyst for the generation of H2O2 in the presence of homocysteine and in the presence of copper, H2O2 undergoes reactions resulting in the generation of O2*-, which reacts with NO to produce peroxynitrite (ONOO-), thereby reducing the bioavailability of NO and impairing NO-mediated relaxation of CC. Smooth muscle strips from CC were obtained from two groups of adult New Zealand White rabbits, one rendered HHC with a diet supplemented with methionine (group 1) and another HHC group that had additional dietary supplementation with penicillamine (group 2). Tissue O2*- levels were measured in each group. After pre-contraction with phenylephrine, relaxation responses of CC strips to carbachol were also assessed in both groups. RESULTS: Methionine supplementation led to profound HHC in all rabbits. Penicillamine in group 2 reduced the total plasma Cu2+ compared to group 1. There was a markedly lower carbachol-stimulated relaxation of CC from HHC rabbits in group 1, with a mean (sem) maximum relaxation of 37 (4)% (six samples), than in group 2, at 58 (6)%. CONCLUSION: These data show that elevated levels in vivo of homocysteine in the rabbit markedly impair NO-dependent relaxation of the CC. Furthermore, this effect appears to be augmented by copper. Further clinical studies on homocysteine and copper status in patients with VED are warranted.     

Effects of platelet-activating factor on nitrergic transmission in rabbit corpus cavernosum

AIM: The information currently available suggests that nonadrenergic noncholinergic (NANC) transmitters, particularly nitric oxide, are involved in the relaxation of penile erectile tissues. Platelet-activating factor (PAF) is a chemical mediator and is involved in many physiological and pathophysiological events. It is well known that several of the vascular actions of PAF are mediated by the generation of nitric oxide. We designed this study to test the hypothesis that PAF has an effect on NANC responses in rabbit corpus cavernosum strips. METHODS: Rabbit corpus cavernosum strips were precontracted with phenylephrine (10(-5) mol/L). Isometric tension changes produced by carbachol (10(-9)-10(-5) mol/L), sodium nitroprusside (10(-8)-10(-5) mol/L) and electrical field stimulation (for 10 s at sequential frequencies of 2, 4, 8, 16, and 32 Hz as square-wave pulses of 50 mV) were recorded with a pressure transducer. These relaxations were compared to those obtained in the presence of PAF. RESULTS: PAF had no effect on endothelium-dependent, endothelium-independent or electrical field stimulation-induced NANC relaxation responses in isolated rabbit corpus cavernosum strips. There was no statistically significant difference between the pD(2) and E(max) values for carbachol or sodium nitroprusside in the presence of PAF. CONCLUSIONS: Our results suggest that PAF does not modify the endothelium-dependent, endothelium-independent or electrical field stimulation-induced NANC relaxation responses in isolated rabbit corpus cavernosum strips.     

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.     

2型糖尿病大鼠血浆同型半胱氨酸与阴茎海绵体内NOS和内源性CO的相关性研究

目的:研究2型糖尿病性大鼠血浆同型半胱氨酸(Hcy)与阴茎海绵体内NOS和内源性CO的相关性。方法:选取3月龄雄性Wistar大鼠50只,随机选取10只为对照组(A组);高糖高脂饲料饲养4周后从其他40只大鼠中筛选出30只构建成功的糖尿病(DM)大鼠模型,随机分成3组:DM大鼠组(B组);胰岛素治疗组(C组)和叶酸+维生素B12治疗组(D组)。8周及12周后注射阿朴吗啡观察各组大鼠阴茎勃起情况。12周后测各组大鼠血浆总Hcy含量及阴茎海绵体内NOS活性和CO含量。结果:与A组比较,B组大鼠血浆Hcy浓度明显升高,阴茎勃起功能明显降低,阴茎海绵体NOS活性和CO含量均下降,差异有显著性(P<0.01)。2型DM大鼠中高Hcy血症发生率为55%。与B组比较,C组和D组中大鼠血浆Hcy浓度显著下降,阴茎勃起功能、阴茎海绵体NOS活性均升高(P<0.01),Hcy与NOS(rA=-0.89,rB=-0.76,rC=-0.91,rD=-0.91)及CO含量(rA=-0.82,rB=-0.77,rC=-0.93,rD=-0.81)均呈负相关。结论:2型DM大鼠血浆中的高Hcy可能是引起阴茎海绵体NOS活性下降、CO含量下降,进而导致DM ED发病的分子机制之一。胰岛素、叶酸和维生素B12可以改善DM大鼠的勃起功能,提高阴茎海绵体NOS活性和CO含量。     

腺病毒介导的激活大鼠阴茎海绵体平滑肌细胞中NO／cGMP通路的实验研究

目的：探讨靶向大鼠iNOS基因的shRNA重组腺病毒载体对大鼠阴茎海绵体平滑肌细胞iN0s基因的激活作用,为阴茎勃起功能障碍（ED）的基因治疗提供实验依据。方法：将前期构建的重组腺病毒AdS—iN—OSrshRNA-EGFP（AdU6／shiNOS）和对照病毒AdU6／shControl,分别转染大鼠阴茎海绵体平滑肌细胞,分别在不同病毒MOI（25,50,75）值下72小时后采样检测。采用realtimeRT-PCR半定量检测AdU6／shiNOS对细胞iNOS基因mRNA表达影响;Western—blot法检测海绵体平滑肌细胞iNOS蛋白表达变化。然后培养基中加L—Arg（10mmol／L）,用酶联免疫法检测病毒转染72小时后海绵体平滑肌细胞内cGMP的浓度变化,记录AdU6／shiNOS对平滑肌细胞内cGMP的影响。结果：AdU6／shiNOS转染大鼠阴茎海绵体平滑肌细胞72小时后,和空白对照组、阴性对照组相比iN0s基因在mRNA和蛋白表达水平均显著上调（P〈O．05）,呈剂量依赖性,MOI一75时RNAa效果最好。而且转染72小时后,实验组原代平滑肌细胞内cGMP水平显著高于对照组及空白组（Pd0．05）。结论：利用腺病毒介导的RNAa技术,提高海绵体平滑肌细胞iN0s基因表达获得成功,可以增加阴茎海绵体平滑肌细胞cGMP水平,激活了NO／cGMP通路,这为勃起功能障碍的基因治疗研究开辟了新的方向。     

Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum

The effect of Cuscuta chinensis extract on the rabbit penile corpus cavernosum (PCC) was evaluated in the present study. Penises obtained from healthy male New Zealand white rabbits (2.5–3.0 kg) were precontracted with phenylephrine (Phe, 10 µmol l⁻¹) and then treated with various concentrations of Cuscuta chinensis extract (1, 2, 3, 4 and 5 mg ml⁻¹). The change in penile tension was recorded, and cyclic nucleotides in the PCC were measured by radioimmunoassay (RIA). The interaction between Cuscuta chinensis and sildenafil was also evaluated. The result indicated that the PCC relaxation induced by Cuscuta chinensis extract was concentration-dependent. Pre-treatment with an nitric oxide synthase (NOS) inhibitor (Nω nitro-L-arginine-methyl ester, L-NAME), a guanylyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ), or a protein kinase A inhibitor (KT 5720) did not completely inhibit the relaxation. Incubation of penile cavernous tissue with the Cuscuta chinensis extract significantly increased cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) in the PCC. Moreover, the Cuscuta chinensis extract significantly enhanced sildenafil-induced PCC relaxation. In conclusion, the Cuscuta chinensis extract exerts a relaxing effect on penile cavernous tissue in part by activating the NO-cGMP pathway, and it may improve erectile dysfunction (ED), which does not completely respond to sildenafil citrate.     

Abnormal protein expression in the corpus cavernosum impairs erectile function in type 2 diabetes

Study Type – Aetiology (case control)
Level of Evidence 3b

OBJECTIVE

To investigate the changes in corporal relaxation, intracavernous pressure (ICP) and associated protein expression that control normal erectile function in rats with type 2 diabetes (T2D), as this disease is part of the ‘metabolic syndrome’ associated with a high rate of erectile dysfunction (ED) in men, resulting from failure of corpus cavernosum‐mediated processes.

MATERIALS AND METHODS

T2D was induced in rats by feeding them with a high‐fat diet (HFD) followed by an injection with low‐dose streptozotocin (STZ); they were then compared with rats that received a normal diet (ND).

RESULTS

Hyperglycaemia and dyslipidaemia were induced in HFD + STZ rats, suggesting that T2D was established. The rats with T2D had associated ED, as both nonadrenergic noncholinergic‐mediated corporal relaxation and increased ICP by cavernous nerve stimulation were significantly attenuated compared to the ND group. Western blot analysis revealed diabetes‐associated lower expression of endothelial and neuronal nitric oxide synthase (e and nNOS), and cGMP‐dependent protein kinase (PKG)‐1α/β expression in penile tissue than in the ND group. Contrary to the proteins that regulate corporal relaxation, there were relatively high levels of RhoA/Rho kinase receptor 1 (ROCK1) and ET‐A receptor (ETAR) in T2D rats. However, the expressed level of phosphodiesterase‐5 and insulin‐like growth factor binding protein 3 was not altered significantly in response to T2D.

CONCLUSION

Decreased expression of certain proteins that mediate the relaxant mechanism, associated with increased expression of certain proteins that mediate contractile mechanisms, might be important in the development of T2D‐associated ED. In particular, down‐regulated eNOS/nNOS/PKG1 as well as up‐regulated ETAR/RhoA/ROCK1 might participate in the aetiology of ED in T2D.     

A functional study of purinergic signalling in the normal and pathological rabbit corpus cavernosum

OBJECTIVE

To examine rabbit cavernosal smooth muscle (CSM) relaxation to ATP, ADP and UTP in normal rabbits and in models of conditions that predispose to erectile dysfunction (ED), diabetes mellitus (DM; induced for 6 months) and bladder outlet obstruction (BOO, 6 weeks after surgery).

MATERIALS AND METHODS

Concentration‐response curves (CRCs) were constructed to ATP, ADP and UTP on CSM from control rabbits in the absence and presence of antagonists. In addition, CRCs were constructed to ATP in CSM from rabbits with DM and BOO.

RESULTS

ATP and UTP caused equipotent, dose‐dependent relaxations of pre‐contracted normal rabbit CSM; ADP was more potent. Relaxation was inhibited by Reactive Blue 2, but not by suramin, 8‐p‐sulfophenyltheophylline or L‐N^G‐nitroarginine methyl ester. In rabbits with DM and those with partial BOO, ATP‐mediated CSM relaxation was less than in control rabbits. Pharmacological profiling suggests that purine‐induced CSM relaxation might be mediated by P2Y₁ and P2Y₄ receptors in the rabbit.

CONCLUSIONS

In healthy rabbits, ATP released from nerves appears to produce relaxation of CSM via P2Y₄ receptors on smooth muscle, while ADP, acting on P2Y₁ receptors on endothelial cells, produces relaxation via nitric oxide. Alterations in CSM purinergic signalling might be implicated in the pathophysiology of ED associated with DM and BOO. Characterization of purinergic signalling in CSM might highlight new therapeutic targets for treating ED.     

阴茎海绵体平滑肌细胞外钙离子浓度在体检测与神经性ED的相关研究

目的 通过钙离子传感针在体检测阴茎海绵体平滑肌细胞外的钙离子浓度,探讨其与勃起功能障碍(ED)的相关性.方法 40只雄性SD大鼠随机分为损伤组(20只)和对照组(20只),通过剪断双侧海绵体神经制作神经性ED模型,1个月后应用钙离子传感针在体检测大鼠阴茎海绵体平滑肌细胞外的钙离子浓度,比较两组间钙离子浓度的差异.结果 损伤组(ED组)钙离子浓度(电位)为(-0.31±0.35)mV,对照组钙离子浓度(电位)为(0.17±0.34)mV,两组钙离子浓度差异具统计学意义(P<0.05).结论 钙离子传感针可以作为ED在体检测的一种新方法.     

Comparative studies on intracellular calcium and nadh fluorescence of the rabbit corpus cavernosum

Erectile function (erection and detumescence) involves the complex interaction of direct neuronal stimulation of corporal smooth muscle, neurohumoral release of specific endothelial contractile and relaxant factors, and secondary modulation by a variety of putative neuropeptides and vasoactive modulators. Using surface spectrofluorometry, we have correlated spontaneous contractile activity and the contractile response to field and pharmacological agents with intracellular calcium and NADH metabolism. The results demonstrate that the corpus cavernosal tissue has very unusual properties. Spontaneous contractile activity is correlated with a phasic increase in intracellular calcium. However, spontaneous contractile activity is most often correlated with a bi-phasic effect on the ratio of NADH/NAD. At the start of the spontaneous contraction, there is a sharp phasic increase in NADH/NAD; peak contractile force occurs simultaneous with a phasic decrease in this ratio showing that at peak force generation, there is a decrease in the level of intracellular energy. Phenylephrine stimulation results in an increase in intracellular calcium in proportion to the increase in tension; however, phenylephrine stimulation at low concentrations results in a net increase in the NADH/NAD ratio whereas high concentrations of phenylephrine result in a net decrease in the NADH/NAD ratio. In general, field stimulation results in a decrease in tension at low frequencies, a biphasic response at midfrequencies, and a contraction at high frequencies. These contractile responses are directly related to alterations in the intracellular concentration of calcium. That is, a decrease in tension is preceded by a decrease in intracellular calcium while an increase in tension is preceded by an increase in intracellular free calcium. Field stimulation results in a rapid and phasic alteration in the NADH/NAD ratio; however, the NADH/NAD response can be either an increase, decrease, or biphasic response. There does not appear to be a consistent relationship between the contractile/relaxant response to field stimulation and altered NADH/NAD ratio. Finally, ATP, bethanechol, and nitroprusside induce a decrease in the basal tension of the corpus cavernosal strips which corresponds with a decrease in the NADH/NAD ratio. However, whereas nitroprusside relaxation is correlated with a decreased intracellular calcium level, both ATP and bethanechol stimulate an increase in intracellular free calcium. These studies indicate that the response of the corpus cavernosal tissue to both field stimulation and pharmacological agents is complex and may involve both direct and indirect actions of a variety of cellular mediators on the corporal smooth muscle. © 1994 Wiley-Liss, Inc.     

Low androgen status inhibits erectile function by up-regulating the expression of P2X receptors in rat corpus cavernosum

The aim of our study was to investigate whether low androgen level inhibits the erectile function of rats by regulating the expression of P2X receptors. Thirty-six 8-week-old male SD rats were randomly divided into six groups: sham-operated groups (4w-sham, 8w-sham), castration groups (4w-cast, 8w-cast) and androgen replacement after castration groups (4w-cast + T, 8w-cast + T). The maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP), the levels of serum testosterone (T) and nitric oxide (NO), and the expression of P2X1, P2X2, P2X3, eNOS, p-eNOS, ROCK1 and ROCK2 in the cavernous tissue of rats were determined. The serum T, ICPmax/MAP and NO levels in penile corpus cavernosum in the castration groups were significantly lower than those in other groups (p < .01). The protein expression of P2X1, P2X2, P2X3, ROCK1 and ROCK2 in the castration groups was significantly higher than those in other groups (p < .01). P-eNOS/eNOS of the castration groups were significantly lower than those of other groups (p < .01). The serum T level was negatively correlated with the expression of P2X1, P2X2 and P2X3 in the corpus cavernosum. Low androgen level inhibits erectile function by up-regulating the expression of P2X1, P2X2, P2X3 and RhoA/Rho-kinase resulting in reducing the ratio of p-eNOS/eNOS and the level of NO in corpus cavernosum of rats.     

The neuronal and endothelium-dependent relaxing responses of human corpus cavernosum under physiological oxygen tension last longer than previously expected

BACKGROUND: Intracavernosal oxygen tension varies greatly in the process of erection. Blood extracted from the human penis demonstrates an increase from approximately 30 mmHg Po(2) in the flaccid state to 100 mmHg in the erect state of the penis. In the present study, using these levels as a guide, we investigate how the NO-dependent relaxation of human corpus cavernosum changed under physiological oxygen tensions ranging from approximately 30 to 100 mmHg. METHODS: Human penile tissue specimens were obtained at penile surgery with informed consent from the patients. The preparations were mounted in Krebs solution in an organ bath and the isometric tension was recorded. Krebs solutions of various oxygen tensions were prepared by bubbling 5% CO(2) in N(2) and O(2). The NO-dependent relaxation caused by electrical field stimulation (EFS) and acetylcholine (ACh) was studied, and the amplitude and duration of relaxation evaluated. RESULTS: The amplitude of relaxation induced by EFS was significantly decreased under physiological oxygen tension conditions (P < 0.01). The duration of the relaxant response induced by EFS and ACh was significantly prolonged in physiological oxygen tension conditions than in high oxygen tension (P < 0.01). However, there was no correlation between the duration of relaxation induced by EFS and each physiological oxygen tension level. The duration of relaxation induced by ACh was most prolonged at 60-69 mmHg oxygen tension. CONCLUSION: Physiologically, the effect of NO may last longer than was previously thought. In addition, it would seem that there is an optimal physiological oxygen tension for maximum ACh-induced relaxation.     

Tolerance to isosorbide dinitrate in isolated strips of rabbit corpus cavernosum

The aim of this study was to investigate whether prolonged exposure to a high concentration of isosorbide dinitrate (ISDN) would result in tolerance being developed against its relaxant activity in strips of corpus cavernosum, pre-contracted by phenylephrine. Under these conditions, relaxation induced by ISDN was found to be significantly reduced. Strips made tolerant to ISDN remained fully responsive to sodium nitroprusside and papaverine. Electrical field stimulation evoked relaxations which were persistent in the presence of tolerance-inducing conditions. These results indicate that desensitization of guanylate cyclase activity is not likely to be the operating mechanism for nitrate tolerance. We suggest that tolerance may result from the impairment of biotransformation of ISDN in rabbit cavernosal smooth muscle.     

自发性高血压大鼠阴茎海绵体组织nNOS变化的实验研究

目的：研究高血压对大鼠阴茎海绵体组织nNOS神经纤维的影响。方法：自发性高血压大鼠(SHR)和同系WKY鼠各12只，都随机分为4周观察组(6只)和12周观察组(6只)。第4周和第12周末时，观察阴茎勃起功能，并检测阴茎组织nNOS神经纤维数目。结果：4周组和12周组中，SHR和WKY鼠在阴茎勃起次数和阴茎组织nNOS神经纤维数目上，都有显著差异(P＜0．01)。SHR4周组和SHR12周组，在阴茎组织nNOS神经纤维数目上，差异也有显著性(P＜0．05)，阴茎勃起次数和勃起率差异无显著性(P＞0．05)，但有减少的趋势。结论：高血压使阴茎组织中nNOS神经纤维数目减少，这可能是高血压引起勃起功能障碍的发病机理之一。     

Effect of hydrogen sulphide‐donating sildenafil (ACS6) on erectile function and oxidative stress in rabbit isolated corpus cavernosum and in hypertensive rats

OBJECTIVE

To study the effect of the H₂S‐donating derivative of sildenafil (ACS6) compared to sildenafil citrate and sodium hydrosulphide (NaHS) on relaxation, superoxide formation and NADPH oxidase and type 5 phosphodiesterase (PDE5) expression in isolated rabbit cavernosal tissue and smooth muscle cells (CSMCs), and in vivo on indices of oxidative stress induced with buthionine sulphoximine (BSO).

MATERIALS AND METHODS

Relaxation was studied in an organ bath in response to carbachol and after incubation with interleukin‐1β for 12 h. CSMCs were incubated with tumour‐necrosis factor‐α or the thromboxane A₂ (TXA₂) analogue, U46619, with or with no sildenafil citrate, ACS6 or NaHS for 16 h. Superoxide formation and the expression of p47^phox (an active subunit of the NADPH oxidase complex) and PDE5 protein was then assessed using Western blotting. Rats were also treated with BSO (with or with no sildenafil citrate or ACS6) for 7 days; cavernosal cGMP, cAMP, glutathionine and plasma TXA₂ and 8‐isoprostane F_2α was measured by enzyme‐linked immunosorbent assay.

RESULTS

ACS6 and sildenafil citrate relaxed cavernosal smooth muscle equipotently; NaHS alone had little effect at up to 100 µm . The formation of superoxide and expression of p47^phox and PDE5 was reduced by ACS6, sildenafil citrate and NaHS (order of potency: ACS6 > sildenafil citrate > NaHS). The effects of ACS6 were blocked by inhibitors of protein kinase A (PKA) and PKG. In rats treated with BSO, both ASC6 and sildenafil citrate reduced the increased plasma levels of TXA₂ and 8‐isoprostane F_2α but increased cGMP, cAMP and glutathionine levels in corpus cavernosum.

CONCLUSIONS

By virtue of a dual action on PKA and PKG activation, ACS6 not only promotes erection, acutely, but might also have a long‐term beneficial effect through inhibition of oxidative stress and downregulation of PDE5.     

不同剂量香烟烟雾提取物对阴茎海绵体NOS活性和Cx43蛋白的影响

目的:探讨不同剂量的香烟烟雾提取物对雄性大鼠勃起功能的影响,进一步研究吸烟导致ED的发病机制。方法:75只健康雄性SD大鼠(8周龄),随机分为5组(15只/组)。A组为对照组;B组为皮下注射二甲基亚砜(DMSO)组;C组为皮下注射香烟烟雾提取物(CSE)低剂量组;D组为皮下注射CSE中剂量组;E组为皮下注射CSE高剂量组。应用SD雄性大鼠建立皮下注射CSE模型60 d后,经皮下注射阿朴吗啡(APO)后观察大鼠阴茎勃起情况,处死大鼠取阴茎海绵体组织。一部分标本采用激光共聚焦扫描显微镜方法检测缝隙连接蛋白43(Cx43)的表达;另一部分标本采用比色法测定大鼠阴茎海绵体组织中NOS活性。结果:不同剂量CSE组阴茎勃起次数、阴茎海绵体组织NOS活性和海绵体平滑肌中Cx43表达与DMSO组和对照组比较均明显减少(P<0.05)。实验组中,阴茎勃起次数、阴茎海绵体组织NOS活性和Cx43表达均随着CSE剂量的增加而减少。DMSO组与对照组比较差异无统计学意义(P>0.05)。结论:CSE使阴茎海绵体组织NOS活性明显降低、海绵体平滑肌中Cx43蛋白表达明显减少并且严重影响阴茎勃起功能,并且CSE剂量越大,其影响越明显。提示,Cx43蛋白表达下调、NOS活性降低可能是CSE导致ED的发病机制之一。