Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Penile constitutive nitric oxide synthase expression in rats exposed to unpredictable chronic mild stress: role of inflammation


Chronic psychological stress cause erectile dysfunction (ED). Considering recent evidence that tumor necrosis factor-α (TNF-α) levels are increased in serum of patients with ED, the present study investigated the effects of infliximab (a TNF-α blocker) on endothelial nitric oxide synthase (eNOS) and neuronal NOS (nNOS) immunoreactivity of rat penile corpus cavernosum in unpredictable chronic mild stress (UCMS). Male adult rats were randomly divided into three groups (n=8 per group): Control, UCMS and UCMS+infliximab. Control and UCMS groups received physiological saline, UCMS+infliximab group received infliximab (5 mg kg−1 per week, intraperitoneally) during 8 weeks of UCMS. UCMS and UCMS+infliximab groups were subjected to different types of stressors, which were randomly applied four to five times during this time period. After 8 weeks, penile eNOS and nNOS expressions were determined immunohistochemically. In UCMS group, nNOS and eNOS immunoreactivity was found to be decreased in penile corpus cavernosum compared with the control group. Whereas in infliximab treatment group eNOS and nNOS immunoreactivity increased compared with the UCMS group. These findings support that UCMS decreases penile constitutive NOS expression via TNF-α, which may contribute to the development of ED. Blockage of TNF-α actions may represent an alternative therapeutic approach for ED in chronic psychological stress.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1
Figure 2


  1. 1

    National Institutes of Health. NIH Consensus Conference. Impotence. NIH Consensus Development Panel on Impotence. JAMA 1993; 270: 83–90.

    Article  Google Scholar 

  2. 2

    Shaeer O, Shaeer K . The Global Online Sexuality Survey (GOSS): the United States of America in 2011. Chapter I: erectile dysfunction among English-speakers. J Sex Med 2012; 9: 3018–3027.

    Article  Google Scholar 

  3. 3

    Shamloul R, Ghanem H . Erectile dysfunction. Lancet 2013; 381: 153–165.

    CAS  Article  Google Scholar 

  4. 4

    Sato Y, Suzuki N, Horita H, Wada H, Shibuya A, Adachi H et al. Effects of long-term psychological stress on sexual behavior and brain catecholamine levels. J Androl 1996; 17: 83–90.

    PubMed  PubMed Central  Google Scholar 

  5. 5

    Retana-Márquez S, Bonilla-Jaime H, Vázquez-Palacios G, Martínez-García R, Velázquez-Moctezuma J . Changes in masculine sexual behavior, corticosterone and testosterone in response to acute and chronic stress in male rats. Horm Behav 2003; 44: 327–337.

    Article  Google Scholar 

  6. 6

    de Souza DB, Silva D, Cortez CM, Costa WS, Sampaio FJ . Effects of chronic stress on penile corpus cavernosum of rats. J Androl 2012; 33: 735–759.

    Article  Google Scholar 

  7. 7

    Willner P . Validity, reliability and utility of the chronic mild stress model of depression: a 10-year review and evaluation. Psychopharmacology (Berl) 1997; 134: 319–329.

    CAS  Article  Google Scholar 

  8. 8

    Rajfer J, Aronson WJ, Bush PA, Dorey FJ, Ignarro LJ . Nitric oxide as a mediator of relaxation of the corpus cavernosum in response to nonadrenergic, noncholinergic neurotransmission. N Engl J Med 1992; 326: 90–94.

    CAS  Article  Google Scholar 

  9. 9

    Dail WG, Barba V, Leyba L, Galindo R . Neural and endothelial nitric oxide synthase activity in rat penile erectile tissue. Cell Tissue Res 1995; 282: 109–116.

    CAS  Article  Google Scholar 

  10. 10

    Andersson KE . Erectile physiological and pathophysiological pathways involved in erectile dysfunction. J Urol 2003; 170: S6–S13.

    Article  Google Scholar 

  11. 11

    Prieto D . Physiological regulation of penile arteries and veins. Int J Impot Res 2007; 20: 17–29.

    Article  Google Scholar 

  12. 12

    Hurt KJ, Musicki B, Palese MA, Crone JK, Becker RE, Moriarity JL et al. Akt-dependent phosphorylation of endothelial nitric-oxide synthase mediates penile erection. Proc Natl Acad Sci USA 2002; 99: 4061–4066.

    CAS  Article  Google Scholar 

  13. 13

    Carneiro FS, Giachini FR, Carneiro ZN, Lima VV, Ergul A, Webb RC et al. Erectile dysfunction in young non-obese type II diabetic Goto-Kakizaki rats is associated with decreased eNOS phosphorylation at Ser1177. J Sex Med 2010; 7: 3620–3634.

    CAS  Article  Google Scholar 

  14. 14

    Atkeson A, Yeh SY, Malhotra A, Jelic S . Endothelial function in obstructive sleep apnea. Prog Cardiovasc Dis 2009; 51: 351–362.

    CAS  Article  Google Scholar 

  15. 15

    Amany S, Heba K . Effect of pregabalin on erectile function and penile NOS expression in rats with streptozotocin-induced diabetes. Exp Clin Endocrinol Diabetes 2013; 121: 230–233.

    CAS  Article  Google Scholar 

  16. 16

    Carneiro FS, Sturgis LC, Giachini FR, Carneiro ZN, Lima VV, Wynne BM et al. TNF-αlpha knockout mice have increased corpora cavernosa relaxation. J Sex Med 2009; 6: 115–125.

    CAS  Article  Google Scholar 

  17. 17

    Carneiro FS, Zemse S, Giachini FR, Carneiro ZN, Lima VV, Webb RC et al. TNF-alpha infusion impairs corpora cavernosa reactivity. J Sex Med 2009; 6 (Suppl 3): 311–319.

    CAS  Article  Google Scholar 

  18. 18

    Lu XT, Liu YF, Zhao L, Li WJ, Yang RX, Yan FF et al. Chronic psychological stress induces vascular inflammation in rabbits. Stress 2013; 16: 87–98.

    CAS  Article  Google Scholar 

  19. 19

    Nystrom T, Nygren A, Sjoholm A . Increased levels of tumour necrosis factor-alpha (TNF-αlpha) in patients with Type II diabetes mellitus after myocardial infarction are related to endothelial dysfunction. Clin Sci (Lond) 2006; 110: 673–681.

    Article  Google Scholar 

  20. 20

    Gao X, Belmadani S, Picchi A, Xu X, Potter BJ, Tewari Singh N et al. Tumor necrosis factor-alpha induces endothelial dysfunction in Leprdb mice. Circulation 2007; 115: 245–254.

    CAS  Article  Google Scholar 

  21. 21

    Zhang H, Park Y, Wu J, Chen X, Lee S, Yang J et al. Role of TNF-alpha in vascular dysfunction. Clin Sci (Lond) 2009; 116: 219–230.

    CAS  Article  Google Scholar 

  22. 22

    Karson A, Demirtaş T, Bayramgürler D, Balci F, Utkan T . Chronic administration of infliximab (TNF-α inhibitor) decreases depression and anxiety-like behaviour in rat model of chronic mild stress. Basic Clin Pharmacol Toxicol 2013; 112: 335–340.

    CAS  Article  Google Scholar 

  23. 23

    Demirtaş T, Utkan T, Karson A, Yazır Y, Bayramgürler D, Gacar N . The link between unpredictable chronic mild stress model for depression and vascular inflammation? Inflammation 2014; 37: 1432–1438.

    Article  Google Scholar 

  24. 24

    Şahin TD, Karson A, Balcı F, Yazır Y, Bayramgürler D . TNF-αlpha inhibition prevents cognitive decline and maintains hippocampal BDNF levels in the unpredictable chronic mild stress rat model of depression. Behav Brain Res 2015; 292: 233–240.

    Article  Google Scholar 

  25. 25

    Andersson KE, Wagner G . Physiology of penile erection. Physiol Rev 1995; 75: 191–236.

    CAS  Article  Google Scholar 

  26. 26

    Gratzke C, Angulo J, Chitaley K, Dai YT, Kim NN, Paick JS et al. Anatomy, physiology, and pathophysiology of erectile dysfunction. J Sex Med 2010; 7: 445–475.

    CAS  Article  Google Scholar 

  27. 27

    Andersson KE . Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction. Pharmacol Rev 2011; 63: 811–859.

    CAS  Article  Google Scholar 

  28. 28

    Lasker GF, Maley JH, Kadowitz PJ . A review of the pathophysiology and novel treatments for erectile dysfunction. Adv Pharmacol Sci 2010; 2010: 1–10.

    Article  Google Scholar 

  29. 29

    Bal E, Murat N, Demir O, Soner BC, Can E, Gidener S et al. Restraint stress impairs erectile responses in rats. Tohoku J Exp Med 2009; 217: 239–242.

    Article  Google Scholar 

  30. 30

    Bodie JA, Beeman WW, Monga M . Psychogenic erectile dysfunction. Int J Psychiatry Med 2003; 33: 273–293.

    Article  Google Scholar 

  31. 31

    Guay A, Seftel AD, Traish A . Hypogonadism in men with erectile dysfunction may be related to a host of chronic illnesses. Int J Impot Res 2010; 22: 9–19.

    CAS  Article  Google Scholar 

  32. 32

    Lenzi A, Lombardo F, Salacone P, Gandini L, Jannini EA . Stress, sexual dysfunctions, and male infertility. J Endocrinol Invest 2003; 26 (Suppl 3): 72–76.

    CAS  PubMed  Google Scholar 

  33. 33

    Vlachopoulos C, Ioakeimidis N, Terentes-Printzios D, Stefanadis C . The triad: erectile dysfunction-endothelial dysfunction-cardiovascular disease. Curr Pharm Des 2008; 14: 3700–3714.

    CAS  Article  Google Scholar 

  34. 34

    Vlachopoulos C, Aznaouridis K, Ioakeimidis N, Rokkas K, Vasiliadou C, Alexopoulos N et al. Unfavourable endothelial and inflammatory state in erectile dysfunction patients with or without coronary artery disease. Eur Heart J 2006; 27: 2640–2648.

    CAS  Article  Google Scholar 

  35. 35

    Vlachopoulos C, Rokkas K, Ioakeimidis N, Stefanadis C . Inflammation, metabolic syndrome, erectile dysfunction, and coronary artery disease: common links. Eur Urol 2007; 52: 1590–1600.

    CAS  Article  Google Scholar 

  36. 36

    Chia S, Qadan M, Newton R, Ludlam CA, Fox KA, Newby DE . Intra-arterial tumor necrosis factoralpha impairs endothelium-dependent vasodilatation and stimulates local tissue plasminogen activator release in humans. Arterioscler Thromb Vasc Biol 2003; 23: 695–701.

    CAS  Article  Google Scholar 

  37. 37

    Anderson HD, Rahmutula D, Gardner DG . Tumor necrosis factor-alpha inhibits endothelial nitricoxide synthase gene promoter activity in bovine aortic endothelial cells. J Biol Chem 2004; 279: 963–969.

    CAS  Article  Google Scholar 

  38. 38

    Thompson IM, Tangen CM, Goodman PJ, Probstfield JL, Moinpour CM, Coltman CA . Erectile dysfunction and subsequent cardiovascular disease. JAMA 2005; 294: 2996–3002.

    CAS  Article  Google Scholar 

  39. 39

    Ponholzer A, Temml C, Obermayr R, Wehrberger C, Madersbacher S . Is erectile dysfunction an indicator for increased risk of coronary heart disease and stroke? Eur Urol 2005; 48: 512–518, discussion 17–18.

    Article  Google Scholar 

  40. 40

    Hayward MD, Jones BK, Saparov A, Hain HS, Trillat AC, Bunzel MM et al. An extensive phenotypic characterization of the hTNFalpha transgenic mice. qBMC Physiol 2007; 7: 13.

    Article  Google Scholar 

  41. 41

    Long T, Liu G, Wang Y, Chen Y, Zhang Y, Qin D . TNF-α, erectile dysfunction, and NADPH oxidase-mediated ROS generation in corpus cavernosum in high-fat diet/streptozotocin-ınduced diabetic rats. J Sex Med 2012; 9: 1801–1814.

    CAS  Article  Google Scholar 

  42. 42

    Spieker LE, Hurlimann D, Ruschitzka F, Corti R, Enseleit F, Shaw S et al. Mental stress induces prolonged endothelial dysfunction via endothelin-A receptors. Circulation 2002; 105: 2817–2820.

    CAS  Article  Google Scholar 

  43. 43

    Neves VJ, Moura MJ, Tamascia ML, Ferreira R, Silva NS, Costa R et al. Proatherosclerotic effects of chronic stress in male rats: Altered phenylephrine sensitivity and nitric oxide synthase activity of aorta and circulating lipids. Stress 2009; 12: 320–327.

    CAS  Article  Google Scholar 

Download references


There is no financial supporter in the current study and this study was presented at 28th ECNP Congress on 29 August to 1 September 2015 in Amsterdam, The Netherlands.

Author information



Corresponding author

Correspondence to T D Şahin.

Ethics declarations

Competing interests

The authors declare no conflict of interest.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Şahin, T., Yazır, Y., Utkan, T. et al. Penile constitutive nitric oxide synthase expression in rats exposed to unpredictable chronic mild stress: role of inflammation. Int J Impot Res 29, 76–81 (2017).

Download citation

Further reading


Quick links