In a new paper, researchers from report brain chemistry that may contribute to why drinkers have difficulty paying attention while under the influence. The work is published in Nature Communications.
"When we want to focus on something, or when we stand up from a chair and become active, a brain stem nucleus releases a chemical called norepinephrine. Acute exposure to alcohol inhibits this signal in the brain," said senior author. When attention is needed for a task, norepinephrine is secreted by a brain structure called the locus coeruleus. Scientists previously did not understand well what happens next, but the team showed that the norepinephrine attaches to receptors on cells called Bergmann glia. This leads to a calcium rise in these cells.
Bergmann glia are astrocytes (caretaker or supporting cells) in the cerebellum, a region near the brain stem. "To our knowledge, this paper is the first description that norepinephrine in mammals directly binds to receptors on the Bergmann glia and activates them through calcium elevation," the senior author said.
The researchers focused on the Bergmann glia but also demonstrated that the same phenomenon occurs in cortical astrocytes. "Most likely vigilance-dependent astrocyte calcium activation is inhibited throughout the brain by acute alcohol intoxication," the author said.
Persons under the influence are off-balance when they walk. The researchers expected to find that the inhibition of calcium rise in Bergmann glia would also explain this. It didn't. "The calcium elevation in Bergmann glia is not critical for motor coordination, which is somewhat surprising because the cerebellum is classically known for its role in motor control," the author said. "However, our findings are in line with current suggestions that the cerebellum also plays critical roles in non-motor functions, and that astrocytes are not only supporting basic brain maintenance, but they may actively participate in cognitive function."
Drinking blocks norepinephrine release that promotes attention
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