NO is produced by the enzyme NO synthase (NOS).  NOS plays many roles, ranging from homeostasis to immune system regulation. To date, 3 subtypes have been identified: nNOS, iNOS, and eNOS, which are produced by the genes NOS1, NOS2, and NOS3, respectively. This nomenclature is derived from the sources of the original isolates: neuronal tissue (nNOS), immunoactivated macrophage cell lines (iNOS), and vascular endothelium (eNOS). The subtypes are not, however, limited to the tissues from which they were first isolated.
A good indicator that "everything is in working order" and that it is probably a psychological cause is if a “morning erection” is still experienced. Feelings like fear, anger, distress and anxiety cause part of the nervous system to come into play which directly blocks the action of another part of the system involved in creating an erection. This is a natural reaction – our ancestors would find it more difficult to run from a predator with an erection in the way!
ED is defined as the inability to achieve a full erection or the inability to maintain an erection adequate for sexual intimacy. Other types of sexual dysfunction such as premature ejaculation and low libido may occur; however, the most common and disruptive problem in men is ED. Although most men will experience periodic episodes of ED, these episodes tend to become more frequent with advancing age.
ED is often the result of atherosclerosis, and as a result, men with ED frequently have cardiovascular disease. Sexual activity is associated with increased physical exertion, which in some men may increase the risk of having a heart attack (myocardial infarction or MI). The major risk factors associated with cardiovascular disease are age, hypertension, diabetes mellitus, obesity, smoking, abnormal lipid/cholesterol levels in the blood, and lack of exercise. Individuals with three or more of these risk factors are at increased risk for a heart attack during sexual activity. The Princeton Consensus Panel developed guidelines for treating ED in men with cardiovascular disease. Thus, if you have ED and cardiovascular disease (for example, angina or prior heart attack), you should discuss whether or not treatment of ED and sexual activity are appropriate for you.
“Cardiovascular exercise and weight resistance exercises increase a man’s testosterone, which helps ward off ED,” Gittens says. The problem is, your testosterone levels drop as you age. Your levels now as a 25-year-old will drop about 50 percent by the time you're 75, according to data from the Reviews of Urology. To keep your levels high, check out this testosterone-boosting workout.
For example, many men with diabetes mellitus may develop erectile dysfunction during their young and middle adult years. Physicians, diabetes educators, and patients and their families are sometimes unaware of this potential complication. Whatever the causal factors, discomfort of patients and health care providers in discussing sexual issues becomes a barrier to pursuing treatment.
Her remark was entirely destructive of poetry, since it was to the effect that poetry had nothing whatever to do with her; all her friends spent their lives in making up phrases, she said; all his feeling was an illusion, and next moment, as if to taunt him with his impotence, she had sunk into one of those dreamy states which took no account whatever of his existence.
Your boyfriend is having a pretty normal problem but because guys are so insecure, they almost never talk about it. That silence often makes guys, especially young guys, panicky — like they’re the only ones in the world dealing with this problem. That freaks them out even more, and that anxiety feeds on itself in a fairly classic and unfortunately common pattern: When a guy has trouble getting it up, he gets so down that the impotence gets worse before it gets better. Anxiety-driven impotence can be a vicious cycle: Quite unlike his dick, the problem just grows and grows.
Erectile dysfunction may be an unpleasant condition that no one really wants to talk about, failing to acknowledge it won’t make the problem go away. Your best defense against health problems like this is to learn everything you can about it so you can tackle the problem at the root. If you’re ready to stop living in embarrassment about your sexual function, become an advocate for yourself and your own health and talk to your doctor.
Hypogonadism may be suggested by the patient's general appearance. If testosterone deficiency antedates puberty, as in Klinefelter's syndrome, eunuchoid proportions—defined as an arm span 5 cm or more in excess of height, or a sole-to-pubis length exceeding crown-to-pubis length by more than 2 cm—may be present. In postpubertal males whose testosterone levels are markedly depressed, the secondary sexual characteristics may become atrophic. Testicles less than 4 cm in length or a prostate gland that is smaller than expected may be the only clues on physical examination to a pituitary tumor with secondary hypogonadism.
The recommended starting dose of tadalafil for use as needed for most patients is 10 mg taken orally approximately one hour before sexual activity. A doctor may adjust the dose higher to 20 mg or lower to 5 mg depending on efficacy and side effects. Doctors recommended that patients take tadalafil no more frequently than once per day. Some patients can take tadalafil less frequently since the improvement in erectile function may last 36 hours. Patients may take tadalafil with or without food. Tadalafil is currently the only PDE5 inhibitor that is FDA-approved for daily use for erectile dysfunction and is available in 2.5 mg or 5 mg dosages for daily use.
The general medical history is important in identifying specific risk factors that may account for or contribute to the patient's erectile dysfunction. These include vascular risk factors such as hypertension, diabetes, smoking, coronary artery disease, peripheral vascular disorders, pelvic trauma or surgery, and blood lipid abnormalities. Decreased sexual desire or history suggesting a hypogonadal state could indicate a primary endocrine disorder. Neurologic causes may include a history of diabetes mellitus or alcoholism with associated peripheral neuropathy. Neurologic disorders such as multiple sclerosis, spinal injury, or cerebrovascular accidents are often obvious or well defined prior to presentation. It is essential to obtain a detailed medication and illicit drug history since an estimated 25 percent of cases of erectile dysfunction may be attributable to medications for other conditions. Past medical history can reveal important causes of erectile dysfunction, including radical pelvic surgery, radiation therapy, Peyronie's disease, penile or pelvic trauma, prostatitis, priapism, or voiding dysfunction. Information regarding prior evaluation or treatment for "impotence" should be obtained. A detailed sexual history, including current sexual techniques, is important in the general history obtained. It is also important to determine if there have been previous psychiatric illnesses such as depression or neuroses.
Normal erectile function depends on the release of NO and endothelial-dependent vasodilation of the penile arteries. The ‘artery size’ hypothesis, first described by Dr Montorsi, offers an explanation why men are more likely to develop ED before a myocardial infacrtion. It is believed that atherosclerosis affects all vascular beds equally but smaller arteries are more likely to become occluded than larger arteries.31 32 The penile arteries are 1–2 mm while the coronary arteries are 3–4 mm. Thus, the same degree of endothelial dysfunction and atherosclerosis is more likely to occlude blood flow in the penile arteries compared with the coronary arteries. The penile arteries therefore serve as a sensitive indicator for subsequent CVD. This theory is supported by the fact that ED occurs approximately 3 years prior to cardiac symptoms in virtually all patients with chronic coronary syndrome whereas patients with acute coronary syndrome have a much lower prevalence of sexual dysfunction.32
Erectile dysfunction can have so many long-lasting effects that the inability to achieve an erection is almost the least of them. Men who suffer from erectile dysfunction often suffer from self-esteem concerns, and these can then translate into issues regarding sexual relationships, friendships, and even work-related relationships. As things begin to spiral out of control, men dealing with erectile dysfunction may go on to suffer from depression, anxiety, and other psychological problems that further inhibit relationship and sexual intimacy. So what is it that’s causing this mess?
medicines called alpha-blockers such as Hytrin (terazosin HCl), Flomax (tamsulosin HCl), Cardura (doxazosin mesylate), Minipress (prazosin HCl), Uroxatral (alfuzosin HCl), Jalyn (dutasteride and tamsulosin HCl), or Rapaflo (silodosin). Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. In some patients, the use of Sildenafil with alpha-blockers can lead to a drop in blood pressure or to fainting