London, March 24 (IANS): There is some good news for those who can't have 'it' up on the spur of the moment! Researchers have devised a gene therapy that triggers reliable erections.

Some men reach for the 'blue pills' to deal with erectile dysfunction. However, Viagra helps only to prolong an erection, it does not actually trigger it.

Researchers from ETH Zurich have now developed a gene therapy that triggers erections even without sexual stimulation.

"In this way, we circumvent the usual sexual stimulation that triggers a cascade of signals in the body and ultimately leads to an erection," said lead researcher Martin Fussenegger.

A gene construct that reacts to blue light is injected into the erectile tissue of the penis.

As soon as it is exposed to the light, a precursor molecule called GTP is converted into the second messenger cyclic called cGMP, which exists naturally in a number of human organs.

This allows voltage-dependent calcium channels to close, thereby reducing calcium levels in the cells, which in turn relaxes muscle cells and increases blood flow to the erectile tissue.

And so the penis becomes stiff.

An enzyme then slowly breaks down cGMP so that the erection wears off with time. Thanks to the gene construct, the production of cGMP is not stimulated by sexual arousal but by exposure of the erectile tissue to blue light.

With erectile dysfunction, normal sexual stimulation does not lead to an erection. The researchers tested their new development in male rats by injecting the gene construct into the erectile tissue with good results.

"The system of an erection is very similar across all mammals," said Fussenegger.