No association found between polymorphisms and smoking or nicotine dependence . . . . . . . . . . . . . . . The researchers found no association between the four SNPs they tested and smoking initiation or nicotine dependence in a population of smokers and non-smokers. The nicotine receptor belongs to a relatively large family of genes involved in mediating the transmission of signals between brain cells. Richard E. Straub, who directs a molecular genetics laboratory at Virginia Commonwealth University, led the study. The scan data support the notion that nicotine addiction is a complex disorder involving many genes.
Normal mice give themselves doses of nicotine when the drug is available.
Nicotine is not habit-forming in mice that lack the primary nicotine receptor, presumably because in these mice the drug never reaches the reward center of the brain. Leonard investigates the role of nicotine receptors in schizophrenia and mental illness, and she hopes Straub's group will screen the entire gene. The four polymorphisms tested in the current study may have functional effects on the gene that the researchers were not able to detect in the sample of some 800 individuals. The researchers compared smoking initiation and progression toward nicotine addiction in nonsmokers, regular smokers with low levels of nicotine addiction, and smokers with high nicotine addiction. The findings appeared recently as a Rapid Communication in the American Journal of Medical Genetics .