Estrogen made by neurons important to making memories

This is Dr. Darrell Brann and graduate student Yujiao Lu Estrogen in the brain is important to keep neurons communicating and memories being made, scientists report. Neurons in both males and females make estrogen and the scientists have shown that when they don’t, their brains have significantly less dense spines and synapses — both key communication points for neurons — in the biggest part of their brain, called the forebrain. "We think this shows estrogen has a clear role in synaptic plasticity, how the neurons communicate and in memory," says Dr. Darrell Brann, interim chair of the Department of Neuroscience and Regenerative Medicine at the Medical College of Georgia at Augusta University. Brann and his colleagues found that mice whose neurons don’t make estrogen have impaired spatial reference memory — like a baseball player not knowing where home plate is and what it means to get there — as well as recognition memory and contextual fear memory — so they have trouble remembering what’s hazardous — they report in the Journal of Neuroscience . Restoring estrogen levels to the brain area rescues these impaired functions, Brann and his colleagues report. It was known that aromatase, the enzyme that converts testosterone to estrogen, was made in the brain’s hippocampus and cerebral cortex in a variety of species that includes humans, Brann says, and that they all can have memory deficits when aromatase is blocked. Patients who take an aromatase inhibitor for estrogen-dependent breast cancer also have reported memory problems. So for these studies in mice, they knocked aromatase out of the forebrain, which includes the hippocampus, which has a role in making long-term memories and spatial memory, and the cerebral cortex, which is important to memory, attention, awareness and thought. They depleted aromatase only in the excitatory neurons — called […]

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