BERKELEY (3/22/00) -- Long suspected to have contributed to psychoses, fits and hallucinations in such famous artists and writers as van Gogh, Poe and Baudelaire, the liqueur absinthe they cherished contained a potent toxin that UC Berkeley scientists now say causes neurons to seriously malfunction.
The researchers report their findings in this week's edition of the journal, Proceedings of the National Academy of Sciences.
"Based on what we've discovered, large consumption of old absinthe would have greatly disrupted the nervous system," said scientist John Casida, a UC Berkeley professor of environmental chemistry and toxicology. "Our findings could explain many of the symptoms described in the literature."
Casida said it was not previously known how the neurotoxin alpha-thujone, found not only in absinthe but also in many popular herbal medicines, acted on the body to bring about poisoning or whether the mechanism could account for strange behaviors noted in many 19th century absinthe drinkers. Vincent van Gogh, Edgar Allen Poe and Charles Baudelaire were among them.
The UC Berkeley researchers discovered that alpha-thujone acts on the same brain receptor responsible for a form of epilepsy. The receptor controls the chloride channel that regulates excitation and keeps neurons under control.
"Basically, alpha-thujone blocks the channel and allows the neurons to fire too easily," said UC Berkeley postdoctoral researcher Karin Höld, co-author of the study along with Casida; fellow UC Berkeley postdoc Nilantha Sirisoma; and two collaborators at Northwestern University Medical School, Tomoko Ikeda and Toshio Narahashi.
"In light of the findings on how alpha-thujone works, it's not surprising that absinthe had such a remarkable effect," Casida said.
Symptoms described, for instance, in Wilfred Niels Arnold's 1992 book on Vincent van Gogh and others who consumed quantities of the popular 19th- and early 20th-century liqueur included forms of bizarre and psychotic behavior, hallucinations, sudden delirium, convulsions, and even suicide and death.
"The question has been sitting around for a century waiting for someone to say how absinthe and alpha-thujone might work," Casida said. "We decided to take a look at it in terms of where the toxin goes in the body and what happens to it."
Absinthe is made from grain alcohol and the common herb wormwood. The herb yields a bitter oil used to produce various formulations of absinthe. This liqueur was very popular until it was banned broadly in the early 20th century.
While the historical aspects are interesting, Casida said he is more concerned about herbal concoctions consumed today that contain alpha-thujone. Many have not been subjected to rigorous toxicology tests, he said, including wormwood oil and cedarleaf oil, which are readily available at herbal medicinal outlets and contain quantities of the neurotoxin. Wormwood oil often is used to treat loss of appetite and stomach, liver and gall bladder disorders. The National Institutes of Health, which funded Casida's study, have slated alpha-thujone products for further scientific review next year.
Absinthe itself isn't the health threat it used to be, said postdoc Nilantha Sirisoma. Still banned in some countries but easily available over the Internet, today's version of the emerald-green alcoholic beverage tends to have very low alpha-thujone levels, although there is a great variation among brands and home brew can be particularly dangerous.
At the moment, "absinthe seems like it's getting more popular," said Höld, who monitors some of the Internet traffic on the subject. "It seems to be kind of an 'in' thing."
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