Post-stroke changes in cortical 5-HT2 serotonergic receptors

Area of Science:

• Neuroimaging
• Neurology
• Radiochemistry

Background:

• Stroke can lead to widespread neurological deficits.
• Serotonin 5-HT2 receptors play a crucial role in brain function.
• Understanding alterations in neurotransmitter systems post-stroke is vital for treatment.

Purpose of the Study:

• To investigate serotonergic 5-HT2-specific binding in unlesioned cerebral cortex of stroke patients using [18F]setoperone PET imaging.
• To determine if stroke affects 5-HT2 receptor distribution volume at equilibrium (DVSe) in cortical areas distant from the lesion.
• To explore the influence of stroke laterality, lesion volume, and localization on these receptor changes.

Main Methods:

• Seventeen chronic stroke patients and 14 age-matched controls underwent [18F]setoperone Positron Emission Tomography (PET) and Magnetic Resonance (MR) imaging.
• The distribution volume of 5-HT2-specific binding at equilibrium (DVSe) was quantified in unlesioned cortical regions.
• Statistical analyses, including covariance analysis for age effects, were performed to compare patient and control groups and analyze lesion-related factors.

Main Results:

• A significant decrease in DVSe was observed in the temporal and frontal unlesioned cortices ipsilateral to the stroke, independent of age.
• These DVSe reductions were similar in patients with left and right strokes and did not correlate with lesion volume.
• The subcortical localization of the stroke significantly impacted the topography of DVSe abnormalities, with more medial lesions causing broader reductions.

Conclusions:

• Stroke can induce significant alterations in serotonin 5-HT2 receptors in large, unlesioned cortical areas.
• The extent and location of subcortical lesions are critical determinants of the pattern of these receptor changes.
• These findings highlight the widespread impact of stroke on neurotransmitter systems and suggest potential therapeutic targets.