Its no secret that smokers often drink, and drinkers often smoke. Addiction scientists believe that alcohol consumption may contribute to increased cigarette smoking; certainly alcohol is considered a major risk factor for relapse during smoking cessation. Similarly, smoking is believed to increase the pleasurable effects of alcohol, and may be a risk factor for alcoholism relapse. Two studies in the March issue of Alcoholism: Clinical & Experimental Research examine the mechanisms underlying the two addictive behaviors. One study uses rodents to investigate the impact that alcohol and nicotine have on dopamine (DA) release in the brain; the other study looks at the impact a drug used to block nicotinic effects called mecamylamine has on alcohols effects for humans. The results collectively suggest that nicotinic mechanisms are involved in alcohol consumption.
We believe that the mesolimbic circuit, which originates in the ventral tegmental area of the brain and projects to the nucleus accumbens, is intimately involved in the reward or reinforcing effects of alcohol and nicotine as well as many other drugs of abuse, said Yousef Tizabi, associate professor and researcher at Howard University College of Medicine and lead author of one of the studies. This circuit mainly utilizes the neurotransmitter dopamine. The release of dopamine in the terminal region of this circuit, the nucleus accumbens, appears to be important for the reinforcing process.
For the Tizabi study, rese
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14-Mar-2002