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Pleasure receptor linked to drinking, study finds WASHINGTON (October 19, 1998 5:38 p.m. EDT http://www.nandotimes.com) - Doctors said Monday they had clearly shown dopamine -- the brain chemical responsible for feelings of pleasure -- is a key factor in alcohol consumption. They only have tested mice so far, but say their research is likely to apply to people and might lead to better drugs for treating alcoholism. Writing in the journal Nature Neuroscience, the team at Oregon Health Science University said a specific brain receptor for dopamine affected whether rats liked to drink alcohol. Receptors are a kind of chemical doorway into cells, and this receptor, known as D2, had a strong effect. "These results are important because they provide a reason for renewed interest in developing treatments that involve D2 dopamine receptors for alcoholism," Tamara Phillips, who headed the study, said in a statement. "If a drug could be developed that specifically blocks these receptors without having adverse side-effects, it might hold promise for reducing alcohol drinking," she said. Scientists have long known that dopamine, known as the "feel-good" chemical, is vital to drug, alcohol and nicotine addiction. But narrowing down the specific chemical mechanism has been difficult. Phillips' team bred mice with and without the D2 receptors. Mice that lacked the receptors drank about half as much alcohol as their siblings when given a choice of alcohol or water. "The altered mice actually show an aversion for alcohol, whereas their normal littermates show a preference," Phillips said. And the genetically altered mice were less sensitive to the effects of alcohol. "The normal littermates show reduced locomotion following an injection of alcohol while the locomotion of the mutant mice did not change," Phillips said. And normal mice stumbled more when they were injected with alcohol. Mice and rats are commonly used for research into the effects of drugs and alcohol. Rats will very eagerly eat cocaine, sometimes starving themselves to get more of the drug. The researchers said much more study is needed to discover what mutations in D2, if any, are linked to alcoholism in people. Copyright 1998 Nando.net Copyright 1998 Reuters News Service janet paterson - 51/10 - almonte/ontario/canada http://www.newcountry.nu/pd/members/janet/ [log in to unmask]