The allergy culprit histamine also boosts our memory
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- Pitolisant, a narcolepsy drug that binds to histamine 3 receptors and raises histamine throughout the brain, improved memory retrieval accuracy by 11% in a University of Oxford trial of 60 healthy volunteers, half of whom received the drug and half a placebo.
- MRI scans of those given pitolisant showed greater connectivity between the brain's histamine-producing regions and the hippocampus, according to the study published in Nature Communications.
- Michael Colwell of Oxford said the boost likely works by changing "novelty-linked arousal" — how alert we feel when seeing new things — and noted this may explain why older antihistamines that crossed into the brain caused memory problems in long-term users.
- Holger Stark of Heinrich Heine University in Düsseldorf, who helped create pitolisant, said patients taking the drug for narcolepsy or Prader-Willi syndrome have reported better attention, though the effect has typically been to normalize impaired cognition rather than enhance it in healthy people.
- Roland Seifert at Hannover Medical School said the finding bridges prior animal and human research on histamine and could drive new interest in treating brain conditions by targeting histamine receptors.
- Colwell cautioned that pitolisant should not be used as a "smart drug," warning it would likely disrupt sleep and harm memory in the long term.
Why it matters: The Oxford trial is the first to confirm in humans what animal studies have long suggested about histamine's role in learning and memory, lending credibility to efforts to treat cognitive conditions by targeting brain histamine receptors. Researchers, however, warned that any practical use must avoid the sleep disruption that pitolisant would likely cause.
