Raising histamine levels boosts long-term memory
According to a fascinating new study, taking a drug that increases histamine levels in the brain could improve performance in long-term memory tests.
Histamine granules within a mast cell.
Histamine carries out multiple roles in the body.
Perhaps most famous for its role in the immune system, histamine also helps regulate gut function and acts as a neurotransmitter.
Thanks to their role in allergic reactions, medications that reduce histamine levels — antihistamines — are commonplace.
Drugs that boost histamine levels are less common, but doctors sometimes prescribe them to treat dizziness.
According to the latest study, however, histamine-boosting drugs might, one day, become more prevalent.
Histamine and memory
Over recent decades, researchers have demonstrated an interesting relationship between increased histamine and improvements in memory. However, currently, they do not fully understand the interaction.
Researchers hope that by studying the interplay between the two, they might glimpse innovative ways of treating individuals with impaired memories, such as dementia.
A new study set out to unwrap another layer of this phenomenon. The scientists wanted to understand how histamine impacts long-term memory.
The team was headed up by Prof. Yuji Ikegaya and Hiroshi Nomura, Ph.D., from the University of Tokyo in Japan. This week, the journal Biological Psychiatry published the findings.
To investigate, they recruited 38 males and females, all in their mid-20s. The researchers asked the participants to memorize images of everyday objects, such as wristwatches and glasses.
A few days later, they tested the participants. The researchers showed them some of the original images mixed in with some that they had not seen before. The researchers asked the participants to identify which of the pictures they had seen in the initial session.
Then, 7–9 days later, the researchers tested the participants again. However, this time, before the trial, the participants took either a placebo or a drug that boosted histamine levels in the brain.
Memory boosted but not for all
As expected, histamine did have a positive impact on some participant’s memory test scores. For individuals with poorer memories, the histamine boost helped them to recognize more images than they did in the first round of tests.
It is also worth noting that histamine only boosted long-term memory — it did not improve any other cognitive abilities.
One finding from the study is especially intriguing. The researchers showed the participants a particular image. However, a few days later, they failed to remember seeing that image. Then, around 1 week later, after histamine treatment, they were able to recall that they had seen the image.