Detail Viagra Information
Treatment
Articles
Contact Us
Google

Mechanism - How Viagra Works

The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which resul ts in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood. Sildenafil has no direct relaxant effect on i solated human corpus cavernosum, but enhances the effect of nitric oxide (NO) by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for degradation of cGMP in the corpus cavernosum.

When sexual stimulation causes local release of NO, inhibition of PDE5 by sildenafil causes increased levels of cGMP in the corpus cavernosum, resulting in smooth muscle relaxation and inflow of blood to the corpus cavernosum. Sildenafil at recommended doses has no effect in the absence of sexual stimulation.

Studies in vitro have shown that sildenafil is selective for PDE5. Its effect is more potent on PDE5 than on other known phosphodiesterases (10-fold for PDE6, >80-fold for PDE1, >700-fold for PDE2, PD E3, PDE4, PDE7, PDE8, PDE9, PDE10, and PDE11). The approximately 4,000-fold selectivity for PDE5 versus PDE3 is important because PDE3 is involved in control of cardiac contractility. Sildenafil is on ly about 10-fold as potent for PDE5 compared to PDE6, an enzyme found in the retina which is involved in the phototransduction pathway of the retina. This lower selectivity is thought to be the basis for abnormalities related to color vision observed with higher doses or plasma levels.

In addition to human corpus cavernosum smooth muscle, PDE5 is also found in lower concentrations in other tissues including platelets, vascular and visceral smooth muscle, and skeletal muscle. The inh ibition of PDE5 in these tissues by sildenafil may be the basis for the enhanced platelet antiaggregatory activity of nitric oxide observed in vitro, an inhibition of platelet thrombus formation in vi vo and peripheral arterial-venous dilatation in vivo.



Cheap Viagra Online

DescriptionSupplierPrice
Viagra-100gm 003 UnitsBusacity$85$28.33
Viagra-100gm 004 UnitsAmer Rx$84$21
Viagra-100gm 005 UnitsBusacity$95$19
Viagra-100gm 005 UnitsInteg $109$21.8
Viagra-100gm 010 UnitsBusacity$148$14.8

Click Here for more Price Comparison

Above table is only a small part of the
Full Price Comparison Table

Click Here for Details
Cheap Viagra Pharmacy







Click Here
More information about
Treatment - Medications and Programs for


  • Erectile-Dysfunction
  • Impotence
  • Premature-Ejaculation





  • New Articles Everday


  • Erectile-Dysfunction
  • Impotence
  • Premature-Ejaculation

  • '

    Overview

  • How Sex Affects The Body
  • Indication for Viagra
  • Benefits Of Viagra
  • What Is Viagra?
  • What Viagra Does Not Do ?
  • Mechanism

  • How Viagra Works
  • Clinical Trial

  • Clinical Trial
  • Taking Viagra

  • How To Take Viagra
  • Dosage And Administration - Viagra
  • Finding The Right Dose For You
  • Overdose

  • Too Much Viagra
  • Warnings

  • Read Before You Take Viagra
  • Side Effect

  • Body As A Whole: - Viagra
  • Cardiovascular And Cerebrovascular
  • Cardiovascular:
  • Digestive:
  • Hemic And Lymphatic:
  • Metabolic And Nutritional:
  • Musculoskeletal:
  • Nervous:
  • Possible Side Effects - Viagra
  • Respiratory:
  • Skin And Appendages: - Viagra
  • Special Senses:
  • Urogenital:
  • Precautions

  • Safety Information - Viagra
  • Carcinogenesis, Mutagenesis, Fertility
  • General
  • Patient Information
  • What To Tell Your Doctor
  • Drug Interaction

  • Viagra And Other Medicines
  • Viagra Is Not For Everyone
  • Q & A

  • Can I Cut My Pills In Half?
  • Can I Take Viagra With Food And Alcohol?
  • Can I Take Viagra With Other Conditions?
  • Does It Automatically Cause An Erection?
  • How Does Viagra Work?
  • How Many Men Have Ed?
  • How Often Can I Take Viagra?
  • How Soon Will It Work?
  • How Well Does Viagra Work?
  • Is Viagra Only For Men With Severe Ed?
  • Is Viagra Safe?
  • What Are The Side Effects?
  • What If Viagra Didn'T Work The First Time?
  • What Is Ed?
  • What Is Viagra?
  • Who Should Not Take Viagra?




  • Overview

  • Mechanism

  • Clinical Trial

  • Taking Viagra

  • Overdose

  • Warnings

  • Side Effect

  • Precautions

  • Drug Interaction

  • Q & A





  • Google
    Resources 1 Resources 1 Resources 1 Resources 1 Resources 1 Resources 1 Resources 1