Viagra started life as a medicine intended to treat angina pectoris. Alfred Nobel - an explosives manufacturer - suffered from angina. In 1890 he was prescribed nitroglycerine (called trinitrin) to relieve the pain of angina attacks. It is still used today. Over 100 years later, the work of Robert Furchgott, Louis Ignarro and Ferid Murad showed that nitric oxide (NO) was an important signalling molecule in the cardiovascular system. It is released from nerve endings and cells lining the walls of blood vessels. The effect is to make the blood vessel relax, or dilate. It is also involved in the prevention of blood clots. In 1998, they received the Nobel Prize for Physiology. The Nobel prizes were set up by the same Alfred Nobel who had been treated with nitroglycerine. Building on this knowledge, research by other groups is being undertaken to develop new medicines which moderate the actions of nitric oxide for the treament of cardiovascular and other disorders. Viagra was developed as a treatment for angina. Its effects as a vasodilator would have surprising results. |