A groundbreaking study reveals that brain histamine may play a far larger role in cognition and psychiatric illness than previously understood.
Researchers from King's College London and the University of Porto have created the first multiscale map of the brain histamine system, linking its genes with brain function, development, and mental health disorders across the human lifespan.
Analyzing data from nearly 50,000 cell nuclei, adult and developing brains, and PET scans, the team found distinct expression patterns of histamine receptors. H1 and H2 were enriched in excitatory neurons, while H3 was found in inhibitory neurons.
A single component accounted for 41% of variance in histamine gene expression, with higher levels in frontal and limbic regions, and lower in the occipital cortex. This spatial signature even predicted H3 receptor binding in independent datasets.
Developmentally, histidine decarboxylase expression peaked early, while H3 receptor expression increased into adulthood. Critically, histaminergic expression correlated with structural brain changes seen in ADHD, major depressive disorder, schizophrenia, and anorexia nervosa.
The atlas provides a new framework for investigating how brain histamine signaling may influence psychiatric risk and cognitive function, potentially opening doors to targeted therapies for depression, ADHD, schizophrenia, and other neuropsychiatric conditions.