University of Pittsburgh
October 18, 2000

PITT RESEARCHERS REVEAL OXIDANTS ARE ESSENTIAL FOR LONG TERM MEMORY

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PITTSBURGH, Oct. 19 -- The popular belief that oxidants are bad for you may not always be accurate, say University of Pittsburgh researchers, who found that a lack of oxidants causes deficiencies in long -term memory formation. The study was published in the Oct. 15 issue of the Journal of Neuroscience.

"There is a large body of literature saying that too many oxidants are bad for you, but our study shows that too little of them may be bad as well. Balance is very important," said Eric Klann, an associate professor in the department of neuroscience, and spokesman for the research team.

Their study used genetically engineered mice to examine long-term potentiation (LTP), a change in neuron communication that is believed to underlie long-term memory formation. The genetically engineered mice produced large amounts of an enzyme that break down an oxidant produced by neurons. It was found that these mice have deficient LTP. In support of these findings, behavioral studies showed mice with normal short-term memory but impaired long-term memory.

"We asked why oxidants would be produced by the body at all. The logical

reason is that they are involved in normal functioning," said Klann. "Reactive oxygen species (ROS), commonly known as oxidants, serve a normal function in signaling pathways, which are responsible for correct neuron functioning, which in turn are responsible for normal brain functioning.

"It is likely that in older people, levels of reactive oxygen species rise tremendously. The rise is likely to be both a cause and a product of degeneration, as well as a decrease in the effectiveness of ROS removal mechanisms," said Klann. "These extremely high levels of oxidants may be toxic, and antioxidants may help, but this is not to say that oxidants produced in moderate levels are bad for you."

Other researchers working with Klann included Edda Thiels, Nathan N. Urban, Guillermo R. Gonzalez-Burgos, Beatriz I. Kanterewicz, and German Barrioneuvo of the department of neuroscience at Pitt, and Charleen T. Chu and Tim D. Oury of the department of pathology at the University of Pittsburgh Medical Center. Thiels, Barrionuevo, and Klann have additional appointments at the Center for the Neural Basis of Cognition, a joint project between Pitt and Carnegie Mellon University.

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