Erectile dysfunction pump.

The discovery could prompt the discovery of drug treatments to help those at highest risk.

This protein it produces plays a role in the growth of blood vessels. but too much of it may increase stroke risk.

Writing in the journal Nature Genetics, the scientists said people with certain forms of a gene called PDE4D may be most at risk.

Proteins from a similar “family”, called phosphodiesterase (PDE), are linked to other illnesses, such as asthma, inflammation and even erectile dysfunction.

This suggests that it may be possible to develop a drug to block the effects of the gene - the male sexual impotence impotence drug Viagra already works by targeting another member of the PDE family.

Solveig Gretarsdottir and colleagues at a company called deCode Genetics in Reykjavik believe this gene is associated with an increased risk of stroke.

They carried out DNA tests on over 1,700 people in Iceland, half of whom had suffered strokes.

The Icelandic population is generally regarded as the best testing ground for geneticists.

This is because the gene pool is relatively pure. Unlike most other countries, there has been little immigration since the first Vikings arrived almost 1,000 years ago.

Scientists working on this latest study say they have identified genetic differences between those people who have had strokes and those who have not.

These differences centre on the gene PDE4D, located on chromosome 5.

They have found that three different isoforms of the gene were expressed at lower levels in people who had strokes.

Isoforms are groups of proteins that are produced by a gene.

They also found different combinations of genes in regions of chromosome 5 flanking the PDE4D gene in people who had strokes.

It is already known that this gene provides the coding which enables a protein called a phosphodiesterase to work.

Stroke risk

But the Icelandic scientists believe that too much of it may increase the risks of atherosclerosis - furring up of the arteries.

This causes the arteries to narrow, which can trigger a stroke.

“We propose that PDE4D is involved in the pathogenesis of stroke, possibly through atherosclerosis, which is the primary pathological process underlying ischemic stroke,” the scientists said.

They believe that blocking the protein in people with these potentially problematic forms of the PDE4D gene could protect them against stroke.

There are already drugs available to do this. These so-called phosphodiesterase inhibitors are used to treat asthma, inflammation and erectile dysfunction, with Viagra probably the best known.

However, much further study is needed before these drugs could be used to treat people who may have a high risk of having a stroke.

Viagra, for one, has potentially serious side effects if taken by men with underlying health problems.

The drug, used by millions of men, slowed the increase in the strength of heart contractions by half.

The Johns Hopkins University study, published in Circulation, found the drug acted as a “brake”.

However, UK heart experts warned men with heart conditions should talk to their doctor about taking the drug to ensure they use it safely.

Mixing this drug with other heart medicines or taking it if you have angina without advice from a health cheap post reply url viagra or GP can be dangerous for heart patients Dr Charmaine Griffiths, British Heart Foundation

Viagra, also known as sildenafil, helps men with erectile dysfunction by making genital blood vessels expand in order to maintain an erection.

The Johns Hopkins team have previously shown Viagra can block the short-term effects of hormonal stress in the heart in mice.

But it had been thought to have little direct effect on the human heart.

Cause of impotence in man

This study looked at 35 men and women, with an average age of 30 and no previous signs of coronary artery disease.

They were all given an injections of an adrenaline-like chemical called dobutamine, which increases heart rate and pumping strength in the same way as emotional or exercise stress, or heart failure.

They were then randomly assigned to either take 100mg of Viagra or a dummy pill before receiving a second injection. Heart function was measured before and after each jab.

After the first injection of dobutamine, the force of heart contraction increased by 150% in both groups.

In the dummy pill group, the same effect was seen after the second injection.

However, in the group treated with Viagra the increased heartbeat was slowed by 50%, resulting in a smaller increase in blood flow and blood pressure generated by the heart in response to chemical stimulation.

No adverse side effects on the heart were seen.

Viagra helps maintain erections by blocking the action of an enzyme which prevents the relaxation of blood vessels in the penis.

The same enzyme, called phosphodiesterase 5 (PDE5A), is also involved in the breakdown of a key molecule, cyclic GMP, which helps control stresses and limit heart enlargement.

Heart warning

Professor David Kass, the cardiologist who led the study, said: “Sildenafil effectively puts a 'brake' on chemical stimulation of the heart.”

He added: “Knowing more about the effects of sildenafil on heart function will allow for safer evaluation of its use as a treatment for heart problems.

“Until now, it was widely thought that drugs like sildenafil had no effects on the human heart and that its only purpose was vasodilation in the penis and the lungs.”

He said further studies should be carried out to more symptom Viagra's immediate and long-term effects on the heart.

Dr Charmaine Griffiths, from the British Heart Foundation, said: “Viagra has been a real advance in treating impotence, which affects nearly half of men between 40 and 70 years old.

“The findings that Viagra affects blood pressure is not surprising - before it was known as a successful treatment for impotence, it was actually being researched for lowering effects on blood pressure.”

But she added: “If you have a heart condition you should check with your doctor before taking Viagra.

“Mixing this drug with other heart medicines or taking it if you have angina (heart pain on exercise) without advice from a health professional or GP can be dangerous for heart patients.”

The drug's maker Pfizer says it is considering submiting an application to European regulatory impotence injection to clear it for sale in pharmacies.

An estimated 27 million men have already used the little blue pill for erectile dysfunction on prescription.

Medics said a change would be welcome but might mean other linked diseases were missed with no health check ups.

Ups and downs

Often, men with erectile dysfunction have underlying health problems such as diabetes, which can be spotted by their GP at the time they come for an anti-impotence prescription.

“If men can buy Viagra and rival anti-impotence drugs over-the-counter without a prescription, this opportunity is missed,” said Dr David Ralph from the Institute of Urology at University College London.

But there would be benefits too, he said, such as combating the problem of Viagra sold illegally on the internet from unknown sources, which may be fake and if taken with some medicines could be fatal.

He said it would be safe to buy over-the-counter provided the pharmacist did the necessary checks to ensure the medication was suitable for the patient.

Embarrassment factor

It might also be a more attractive option to men as going to see the GP about sexual problems can be male erectile dysfunction
, he added.

But he cautioned: “There is more to sexual relations than an erection. There may be other problems.”

Viagra works by relaxing the blood vessels in the penis. This allows blood to flow into the penis causing an erection.

However, the drug is not an aphrodisiac and does not increase sex drive.

It is licensed only as a treatment for men who have been diagnosed by a doctor as having impotence.

Also, some men, such as those with severe heart disease or low blood pressure, should avoid it because of possible risks and side effects.

Viagra is not licensed for use in women and its safety in women has not been established.

A Pfizer spokesman said: “As with many of our products, Pfizer has routinely evaluated a number of options including different formulations, new trimix impotence
, over-the-counter and continues to do so.”

He added that despite clinics that treat impotence
there were no plans to pursue a spray version of the drug.

The exercises were found to help men with erectile dysfunction as much as taking in Viagra.

The researchers say the findings mean men have an herbal remedy for erectile dysfunction to drug therapy.

For around 50 years, women have been advised to perform pelvic floor exercises to strengthen their muscles for childbirth.

The pelvic floor is a “hammock” of muscles which support the bowel and bladder.

Pelvic floor, or Kegel, exercises involve clenching the muscles you would use to prevent yourself urinating.

This latest research indicates it is also important for men to maintain the muscle tone and function of their pelvic floor muscles with the exercises.

Home exercises

The team from the University of the West of England in Bristol studied 55 men with an average age of 59 who had experienced erectile dysfunction for at least six months.

The men, all patients at the Somerset Nuffield Hospital, Taunton, Somerset, were given five weekly sessions of pelvic floor exercises and assessed at three and six months, and asked to practise the exercises daily at home.

It was found 40% of the men regained normal erectile function - some of who had severe erectile dysfunction, and another 35% showed some improvement.

Two thirds of the men had said they also had problems with urination. These improved significantly after they began the exercises.

Dr Grace Dorey, a specialist continence mental health treatment plan
who carried out the research, told BBC News Online: “The exercises were found to be equally as effective as taking Viagra.

“Pelvic floor exercises improve function in a physical way, in a more natural way.

“Men should be doing dysfunction erectile male sexual exercise. It really is use it or lose it.”

She said men should be exercising their pelvic floor exercises from puberty onwards.

Strength

A spokesperson for the Impotence Cause of erectile dysfunction
said: “The value and effectiveness of pelvic floor exercises should not be underestimated when considering the management of sexual problems such as impotence and premature ejaculation.

“The exercises are thought to strengthen the muscles that surround the penis and improve the blood supply in the pelvis, which is an important factor in relation to erectile dysfunction.”

The Impotence Association helpline number is 0208 767 7791.