Guwahati, Feb. 10 -- Christian Goritz, Karolinska Institutet

Have you ever wondered how penile erection works but never dared to ask? Well, imagine a dry sponge in a condom. Now pour water on the sponge (that's the blood flowing in). There you have it.

This penis "sponge" is scientifically termed corpora cavernosa. Erections depend on the influx and trapping of blood. Smooth muscle cells regulate the blood flow into the sponge and its subsequent firmness. In a recent study, my colleague and I delved into the role of penile fibroblasts, the most abundant cells in the human penis, about which little was previously known.

We discovered that penile fibroblasts help smooth muscle cells to relax. Using a technique to render cells light-sensi...