Nicotine activates more than just the brain's pleasur...( Durham N.C. Duke University Medical...)

Durham, N.C. Duke University Medical System researchers have discovered there are differing taste pathways for nicotine, which could provide a new approach for future smoking-cessation products.

"We learned some of nicotine's secrets," said Albino Oliveira-Maia, M.D., Ph.D., a postdoctoral fellow of the Duke Department of Neurobiology. "This is the first study to explore both the peripheral taste pathways activated by nicotine, and how these pathways are integrated in sensory areas of the brain." The peripheral nervous system refers to nerves that are outside of the brain and spinal cord.

Using genetic engineering and measurements of nervous system activity in mice, the researchers found that nicotine sends signals directly to the brain's sensory systems by several pathways, similar to the way taste is perceived.

These findings complement what is known about the effects of nicotine in the dopamine pathway. This is the classic pleasure pathway in the brain, much studied by addiction experts. "Our study in no way contradicts prior findings about nicotine and dopamine," Oliveira-Maia said. "Our findings add to what is known and suggest new approaches for further study."

The findings appeared in the PNAS Early Edition slated for January 19.

"One reason that our findings are interesting is because they relate to previous work that looked at humans with lesions in the insula region of the brain they had an easier time giving up cigarettes than most people," Oliveira-Maia said. "We found that a part of the insula, the gustatory cortex, has robust responses to nicotine and a capacity to integrate diverse peripheral information to create a unique sensory representation for nicotine."

One taste pathway the Duke researchers uncovered involves nicotinic acetylcholine receptors (nAChR), which scientists previously proposed were taste receptors for nicotine. The researchers found a previously unknown link bet
'/>"/>