SAN DIEGO--It's no secret that guzzling alcohol kills brain cells. Now, research presented here 14 November at the Society for Neuroscience meeting shows that, in rats, a 4-day bender also cuts the production of new brain cells by half. Adding insult to injury, the scientists found that cells born during the binge die sooner too.
Though it was long believed that the adult brain can't generate new neurons, that idea was proven wrong several years ago. One region where new brain cells arise is the hippocampus, a key learning and memory center. Given that alcoholics often struggle with learning and memory, Kim Nixon and Fulton Crews of the University of North Carolina, Chapel Hill, examined the effects of bingeing on the generation of new brain cells in the hippocampus.
Using a catheter, the pair piped alcohol into the stomachs of male rats; a control group received an equal volume of sugar water, matched for calories. The drunken animals maintained a blood alcohol level of 0.35% for 4 days, comparable to that of chronic alcoholics. The researchers also gave both groups daily injections of a chemical that stains new cells. Examining the brains of half the rats immediately after the binge, Nixon and Crews found about 2500 new brain cells in the teetotalers, but only 57% as many in the drinkers. A month later, when they studied the remaining rats, they found that while the control group had lost about half the estimated number of cells they'd produced, nearly all the new cells in the alcoholic group had died. Next, Nixon plans to determine whether alcohol prevents neuron birth for months on end.
"It raises more questions than it answers, which I think good findings should do," says neuropharmacologist Judson Chandler of the Medical University of South Carolina in Charleston. Chandler notes that the big puzzle is whether the deficit of new neurons in the rats' hippocampus can be linked to the learning and memory problems seen in human alcoholics.