London, Feb 1 (IANS) Do you know why it is so fiendishly difficult to quit smoking – because of a faulty receptor in the brain.

It can lead to an uncontrollable desire to smoke, thanks to the defect in a receptor protein normally activated by nicotine, which curbs the desire for yet more of the drug.

The team found that when rats were genetically changed to block the protein, they consumed far more nicotine than control animals, the Daily Mail reported quoting the journal Nature.

Professor Paul Kenny of the Scripps Research Institute in Florida, US, said: ‘These findings point to a promising target for the development of potential anti-smoking therapies.’

The study specifically focused on the chemical alpha-5 in a brain pathway known as the habenulo-interpeduncular tract.

Co-researcher Christie Fowler said: ‘It was unexpected that the habenula, and brain structures into which it projects, play such a profound role in controlling the desire to consume nicotine.

‘The habenula appears to be activated by nicotine when consumption of the drug has reached an adverse level. But if the pathway isn’t functioning properly, you simply take more.’

She said the data could explain why some people are far more vulnerable to the addictive properties of nicotine and more likely to develop smoking-associated diseases such as lung cancer.