Male impotence – erectile dysfunction

   About Viagra Health news

Male impotence (erectile dysfunction) are concepts that have long been known and bothering people of different races and classes. Many centuries ago, when the mechanisms of erection were not known, they tried to explain male sexual impotence with the evil eye and witchcraft. Aristotle was the first to try to describe the mechanism of erection. The theory proposed by him about the injection of air into the penis during arousal is far from the true mechanisms of the formation of an erection, but it gives us the opportunity to assert that these questions have interested mankind for more than one century.

Male impotence

The first anatomically correct description of the penis belongs to the great artist and talented researcher of the human body, Leonardo da Vinci. He described the mechanism of erection, which develops due to the filling of the penis with blood. In the last century, the word “impotence” was often used in the general lexicon as an offensive expression in relation to a man. The medical term has become a nationwide swear word and a shameful expression. In this situation, it became necessary to introduce a term for the definition of pathology. In 1992, the term “erectile dysfunction” (ED) was adopted. Some time later, a full definition of this condition appeared – this is the inability to achieve and/or maintain an adequate erection of the penis, which limits or makes it impossible to perform sexual intercourse in 50 or more percent of cases. It is necessary to pay attention to the fact that sexual failures are possible in practically healthy men, and it is possible to talk about the disease only when failures become a pattern.

In 1987, the mechanisms of hemodynamics in the penis were described, in 1989-two circulatory circles, one of which functions at rest and provides the trophic needs of the organ, and the other provides a two-to three-fold increase in blood flow during sexual arousal and ensures the occurrence of an erection. In the functional cycle of cavernous hemodynamics, different authors distinguish from 2 to 8 phases. At rest, the spiral (glycine) arteries and smooth muscles of the cavernous bodies are reduced. The blood supply to the organ is carried out through the genital arteries and capillaries (blood flow) with outflow through the veins of the subtunical plexus into the perineal and deep drainage system of the penis. This system performs a trophic function. In this state, the sympathetic tone of the ANS prevails, which is carried out through postsynaptic alpha-1-adrenoreceptors.

The trigger of an erection is a sexual stimulus (visual, tactile, olfactory), which affects the cerebral cortex. The consequence of this effect is the transmission of a neuroendocrine signal to the cells of the smooth muscles of the penis. The tone of the parasympathetic nervous system increases, the activation of beta2-adrenoreceptors of the helicin arteries increases, which leads to their dilation. The tumescence phase is characterized by relaxation of the smooth muscles of the cavernous sinuses, an increase in blood flow to the cavernous bodies and an increase in intracavernous pressure. Relaxation of the smooth muscle elements of the cavernous bodies and cavernous arteries is the leading peripheral mechanism of erection. Currently, quite a lot of mediators that potentiate relaxation have been described, for example, purine derivatives (adenosine), which acts through the postsynaptic purine receptors P1 and P2, carbon monoxide produced by hemoxygenase of the genitourinary tract, prostaglandins, for example, PgE1, acting through prostanoid receptors.

male impotence

The most studied is the effect of nitric oxide as a mediator that provides relaxation of smooth muscle cells of the cavernous arteries and trabeculae. Nitric oxide (NO) is formed from L-arginine under the influence of NO-synthase and is released from nonadrenergic noncholinergic nerve endings and endothelial cells. NO, due to the activation of guanylate cyclase, leads to the movement of calcium ions from the cytosol of cells inside the endoplasmic reticulum and outside the cell matrix. Due to a decrease in the concentration of calcium ions in the cytosol, there is a decrease in the tone of the actomyosin cytoskeleton, and as a result, relaxation of smooth muscle cells. The enzyme phosphodiesterase type V (PDE-5) destroys cGMP with the formation of an inactive peptide 5TMF, thus preventing the relaxation of smooth muscle cells.

The veno-occlusive mechanism ensures the formation of a full erection phase, during which the subtunical venules are compressed by the stretched cavernous sinuses to the protein membrane, providing a blockade of venous outflow with a continuing high arterial inflow. Reflex contractions of the bulbo-cavernous and ischiocavernous muscles, reflex spasm of the distal envelopes of the venules provide additional restriction of venous outflow and form a phase of rigid erection, characterized by almost complete absence of both blood inflow and outflow to the cavernous bodies. At the moment of ejaculation, the sympathetic part of the ANS is activated, accompanied by a decrease in arterial inflow and an initial contraction of the smooth muscles of the cavernous sinuses against the background of an activated veno-occlusive mechanism. The main characteristic of the detumenescence phase is the inactivation of the veno-occlusive complex, which leads to the return of the penis to a state of rest.

Erection of the penis

Penile erection is a neuro-vascular process that results from the interaction of three physiological systems: the central nervous system, peripheral innervation of smooth muscle tissue of the arteries and trabeculae of the cavernous bodies of the penis. Violations at any level can lead to the formation of male impotence. Based on this, it is possible to classify ED by forms as: organic-due to vasculogenic (arterial and/or venous), neurological, hormonal and cavernous disorders or lesions; psychogenic-caused by the central suppression of the mechanism of erection without physical trauma; mixed or organo-psychogenic-caused by a combination of organic and psychogenic factors. The latter form is the most common. Many authors regard ED not as an independent disease, but as a common symptom of a sexual disorder, which has many etiological factors and can become a predictor and / or a symptom of certain diseases, for example, such common as type 2 diabetes mellitus, CHD and depression. A study conducted in 2002 Montorsi et al., showed that out of 90 patients suffering from ED who were monitored for 4 years, 36 (40%) developed coronary heart disease. 73% of patients who had a myocardial infarction or acute coronary syndrome had ED before the heart attack.

Various methods are used to diagnose ED. First of all, there are a number of questionnaires that allow you to assess the severity of this disease and assume the genesis of ED. Patients are not always willing to talk about their problems, often shy of “defeats” in sex, and independently aggravate the psychological component of erectile dysfunction. Lack of education and excessive modesty often become fertile ground for the formation of violations of an already organic nature. One of the most common questionnaires is the “International Index of Erectile Dysfunction” (IIEF). It allows you to assess the state of sexual health of each patient, but is not able to fully answer questions about the presence and level of organic damage, if any. To exclude the vascular genesis of male impotence, a test with intracavernous administration of the drug was previously used, followed by an assessment of the blood filling of the penis according to Doppler scanning data.

Male impotence: Medications

In 1998, for their work on medicine and physiology “Nitrogen monoxide as a signaling molecule in the cardiovascular system”, a group of scientists R. Furchgott, F. Muerada, L. Ignarro became Nobel Prize laureates, and they opened the era of research on the effect of NO on various tissues of the human body. In the same year, the first inhibitor of PDE-5 – sildenafil citrate (Viagra) appeared. The drug was recommended to be taken an hour before sexual intercourse, not accompanied by the intake of fatty foods and alcohol. Three Viagra dosages were presented at once on the medical pharmaceutical market: 25, 50 and 100 mg. The initial dose was recommended to be 50 mg. If there is insufficient effectiveness and no undesirable effects, the dose is increased to 100 mg; with severe adverse reactions, the dose can be reduced to 25 mg.

Cialis, to a lesser extent than Viagra, affects PDE-6, an isoenzyme contained in the retina of the eye, when blocking it, color perception disorders occur. This explains the low frequency of side effects such as visual disorders (color perception) when taking Cialis. On the other hand, Cialis is less selective to PDE-11 compared to Viagra and Levitra, but the blockade of this isoenzyme is not accompanied by any registered clinical effects. According to W. Hellstrom et al. (2003), daily intake of Cialis at a dose of 10 or 20 mg per day for 6 months does not have a negative effect on spermatogenesis.

All drugs of this group potentiate the vasodilating effect and anticoagulant effect of nitrates and NO donors (Angulo et al., 2001; Bischoff et al., 2001). For example, vardenafil (Levitra) has a weak hypotensive effect and reduces blood pressure by a maximum of 5-10 mm Hg (Sache and Rohde, 2000), and also increases the heart rate when used at a dose of 40 mg (Sachse and Rohde, 2000). For these reasons, Levitra should not be prescribed for severe arterial (including orthostatic) hypotension.

Treatment of elderly patients with PDE-5 inhibitors should be started with low doses due to changes in the pharmacokinetics and pharmacodynamics of drugs in these patients and, as a result, an increase in the maximum concentrations of the drug in plasma and the duration of the half-life (Porst et al., 2001).

It should be remembered that it is possible to recommend taking any drugs of this group on a regular basis only after conducting a sensitivity test that excludes the organic genesis of erectile dysfunction.

No Comments

Leave a Reply

Your email address will not be published.