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Solas, M. (Maite); Van-Dam, D. (Debby); Janssens, J. (Jana); et al. "5-HT7 receptors in Alzheimer's disease". Neurochemistry International. (150), 2021, 105185
Even though the involvement of serotonin (5-hydroxytryptamine; 5-HT) and its receptors in Alzheimer’s disease
(AD) is widely accepted, data on the expression and the role of 5-HT7 receptors in AD is relatively limited.
Therefore, the objective of the present work was to study the expression of serotonergic 5-HT7 receptors in
postmortem samples of AD brains and correlate it with neurotransmitter levels, cognition and behavior. The
study population consisted of clinically well-characterized and neuropathologically confirmed AD patients (n =
42) and age-matched control subjects (n = 18). Reverse-transcription quantitative polymerase chain reaction
(RT-qPCR) and high-performance liquid chromatography were performed on Brodmann area (BA) 7, BA10,
BA22, BA24, hippocampus, amygdala, thalamus and cerebellum to measure mRNA levels of 5-HT7 receptors
(HTR7), as well as the concentrations of various monoamine neurotransmitters and their metabolites.
Decreased levels of HTR7 mRNA were observed in BA10. A significant association was observed between
HTR7 levels in BA10 and BEHAVE-AD cluster B (hallucinations) (rs(28) = 0.444, P < 0.05). In addition, a
negative correlation was observed between HTR7 levels in BA10 and both MHPG concentrations in this brain
region (rs(45) = -0.311; P < 0.05), and DOPAC levels in the amygdala (rs(42) = -0.311; P < 0.05). Quite sur-
prisingly, no association was found between HTR7 levels and cognitive status. Altogether, this study supports the notion of the involvement of 5-HT7 receptors in psychotic symptoms in AD, suggesting the interest of testing antagonist acting at this receptor to specifically treat psychotic symptoms in this illness.