Cholecystokinin (CCK) and the CCKA receptor gene polymorphism, and smoking behavior.

We analyzed genetic variants of the promoter region of the cholecystokinin (CCK; which modulates the release of dopamine) gene, and intron 1 and exon 5 of the CCKA receptor gene, and performed association analyses of nicotine dependence using an allele-specific amplification (ASA) method and PCR-RFLP methods. There was a significant difference between the current smoking and nonsmoking groups in the allele frequency of the CCK-45C/T polymorphism. However, there was no significant difference in the CCKA PstI polymorphism, and the HincII polymorphism was not detected in our study. Our data suggest that polymorphisms of the CCK gene may be one of the risk factors for smoking behavior.