Chunk #24 — Candidate Gene Association Studies for Alcohol and Nicotine Dependence — Other Candidate Genes — Genes Potentially Associated with Multiple Disorders
Linkage analyses by COGA investigators suggested that a region on chromosome 7 also was associated with the risk for alcoholism. Closer examination of this broad linkage region identified a candidate gene called CHRM2 (Wang et al. 2004). This gene encodes another neurotransmitter receptor called the muscarinic M2 receptor, which interacts with the neurotransmitter acetylcholine.2 Nerve cell systems using acetylcholine as a neurotransmitter (i.e., cholinergic systems) have long been implicated in depression. For example, compounds that mimic the effects of acetylcholine (i.e., cholinergic agonists) can induce a depressed mood in animals and humans (Bymaster and Felder 2002). In mice, the muscarinic M2 receptor also appears to be involved in mediating certain stress responses (Hemrick-Luecke et al. 2002).
