Healthcare (Commonwealth Union) – Histamine has a variety of functions in relations to the immune system, gastrointestinal track and the nervous system.
Scientists from the King’s College London in the UK and the University of Porto in Portugal have created the first detailed map of the brain’s histamine system. Although histamine is widely known for its role in allergic reactions, it also has a distinct and less-understood function in brain activity. This study fills that knowledge gap by producing a multiscale map linking histamine from genetic mechanisms to behaviour and associated mental health conditions.
Published in Nature Mental Health, the findings offer a new perspective on how this often-overlooked chemical system influences brain function and could inform potential treatments for histamine-related disorders, including depression, ADHD, and schizophrenia.
Histamine acts as a neurotransmitter, a chemical essential for communication between neurons. Historically, neuroscience has focused more on neurotransmitters like dopamine and serotonin, leaving histamine less explored.
Histamine interacts with neurons through specific proteins called receptors, which determine how the chemical signal affects the receiving neuron. Multiple types of histamine receptors exist, each capable of producing different effects on neuronal activity.
Dr Daniel Martins, who is a visiting senior research fellow at King’s College London, as well as the first author for the paper indicated that this study lays an important groundwork for upcoming research. By combining molecular biology, brain imaging, and computational techniques, it presents a fresh view of how neurotransmitter networks are structured throughout the human brain. He further indicated that as neuroscience advances toward more integrated and individualized models of mental health, gaining insight into systems such as histamine could be key to developing novel strategies for diagnosis and therapy.
By mapping the histamine system, researchers discovered that distinct histamine receptors are present on brain cells that either enhance activity (excitation) or suppress it (inhibition). This indicates that histamine may play a key role in regulating the balance between excitation and inhibition, a critical aspect of healthy brain function.
Forming a detailed map of histamine in the human brain was a key focuss of the researchers. To develop a thorough understanding of histamine’s role in the brain, the team integrated genetic and molecular data with anatomical brain maps. This approach identified which regions of the brain receive stronger input from histamine and which areas have a higher capacity to respond to it. These molecular insights were then combined with positron emission tomography (PET) scans of histamine receptors in living participants, along with functional neuroimaging databases that link brain regions to specific cognitive tasks and mental health conditions. PET scans track a small amount of radioactive tracer in real time, revealing how different areas of the brain are functioning.
The study gives a chance for researchers to see the connection between brain functions and psychiatric disorders. Regions with higher expression of histamine-related genes were consistently linked to functions such as emotional regulation, stress and fear responses, decision-making, impulsivity, reward processing, sleep, and memory.
Moreover, the brain areas where histamine-related genes were most active largely overlapped with regions known to be affected in several psychiatric disorders, including ADHD, major depression, schizophrenia, and anorexia nervosa. These findings support earlier theories suggesting a role for histamine in these conditions.
The study indicate that histamine signalling could play a role in making certain brain regions more susceptible to these disorders.
Dr. Daniel Martins, visiting Senior Research Fellow and lead author of the study indicated that this backs the increasingly accepted perspective in psychiatry that mental health conditions stem from disturbances across interconnected brain networks rather than a single chemical imbalance.
This newly created map provides a neural blueprint of a molecule that has received relatively little attention. It paves the way for future research to explore precisely how histamine functions in different cell types and brain regions.
“We want to emphasise that these findings are hypothesis-generating and based on large-scale datasets that capture patterns rather than direct mechanisms,” said Professor Steve Williams, Professor of Neuroimaging who is a senior author for the paper.
