VIAGRA SAID TO BOOST THAT LOVING FEELING.

Impotence drugs such as Viagra may do more than help men physically have sex - they may also boost levels of feel-good hormone, US researchers reported on Thursday.
Viagra, known generically as sildenafil, raised levels of the HORMONE OXYTOCIN in rats, the team at the University of Wisconsin - Madison said in a report published in the Journal of Physiology.

The hormone is involved in nursing and childbirth but also in ORGASM and feelings of SEXUAL PLEASURE. And it seems Viagra and related drugs act on the part of the brain that controls the release of oxytocin, said Wisconsin physiology professor Meyer Jackson.

Viagra, made by Pfizer Inc, is an inhibitor of an enzyme called phosphodiesterase type 5, it blocks this enzyme, which in turn breaks down other compounds. This increases blood flow in the muscles but it also affects a brain structure known as the posterior pituitary. This , in turn, boost oxytocin, at least in the rats. It probably does the same thing in people, Jackson said.

Oxytocin has been known for years to be involved in labour, and it is the hormone that causes the "let-down" of milk in lactating mothers. Only in recent decades has it been found to have a function in men - in sexual arousal and function.

This could suggest other uses for Viagra and related drugs, Jackson said - perhaps promoting social bonding.