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Serotonin may play important role in aging brain, dementia

Recent findings suggested the serotonin system may be an effective target for prevention and treatment of mild cognitive impairment.

“Now that we have more evidence that serotonin is a chemical that appears affected early in cognitive decline, we suspect that increasing serotonin function in the brain could prevent memory loss from getting worse and slow disease progression,” Gwenn S. Smith, PhD, of Johns Hopkins University School of Medicine, said in a press release.

To assess the role of serotonin in mild cognitive impairment, researchers conducted MRI and high-resolution PET among 28 individuals with mild cognitive impairment and 29 healthy, cognitively normal controls. Mean age was approximately 66 years.

Serotonin transporter availability was lower among participants with mild cognitive impairment in cortical and limbic areas typically affected by Alzheimer’s disease and sensory and motor areas relatively unassociated with the disorder, according to researchers.

Reduction in serotonin transporter among participants with mild cognitive impairment was greater than grey matter atrophy or reductions in regional cerebral blood flow, compared with controls.

Lower cortical serotonin transporters were associated with poorer auditory-verbal and visual-spatial memory in mild cognitive impairment but not among controls.

“The results of the present study demonstrate lower [serotonin transporters] in cortical, striatal, thalamic and limbic regions in [mild cognitive impairments] relative to controls. Grey matter atrophy and reductions in regional cerebral blood flow in mild cognitive impairment compared to controls was more localized and less statistically robust than the reductions in [serotonin transporters]. The reduction in [serotonin transporters] is associated with greater impairment in auditory-verbal and visual-spatial memory in [mild cognitive impairments],” the researchers wrote. “Studies are in progress to determine whether serotonin degeneration may be involved in the transition from [mild cognitive impairments] to dementia and to relate serotonin degeneration to other aspects of [Alzheimer’s disease] neuropathology (eg, beta-amyloid and tau).” – by Amanda Oldt

Disclosure: The researchers report no relevant financial disclosures.