From MedicalXpress:
# Scanning synaptic receptors: New imaging method sheds light on psychiatric disorders
Quote:
In this study, Takahashi and colleagues conducted PET scans of the brains of 149 patients with psychiatric disorders. Using the [11C]K-2 tracer, they visualized the density of AMPA receptors throughout different regions of the brain and explored its relationship with disease severity for ASD, depression, schizophrenia, and bipolar disorder.
In addition to this, the team also compared AMPA receptor density between patients with these disorders and healthy subjects.
“Identifying both unique and shared brain regions with altered AMPA receptor density offers new insights into the biological mechanisms of psychiatric disorders,” highlights Takahashi.
Their analysis suggests that an overall reduction and/or an unbalanced distribution of AMPA receptors could underlie the origin of various psychiatric disorders. It also revealed interesting characteristics of each disease. For example, in schizophrenia, the areas associated with positive symptoms (such as hallucinations) did not always overlap with areas associated with negative symptoms (such as lack of motivation and reduced emotional expression).
Original paper, with free reading access, is here.
The abstract says that they have analyzed 42 patients with schizophrenia:
Synaptic phenotypes in living patients with psychiatric disorders are poorly characterized. Excitatory glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) is a fundamental component for neurotransmission. We recently developed a positron emission tomography (PET) tracer for AMPAR, [11C]K-2, the first technology to visualize and quantify AMPARs density in living human brain. In this study, we characterized patients with major psychiatric disorders with [11C]K-2. One hundred forty-nine patients with psychiatric disorders (schizophrenia, n = 42; bipolar disorder, n = 37; depression, n = 35; and autism spectrum disorder, n = 35) and 70 healthy participants underwent a PET scan with [11C]K-2 for measurement of AMPAR density. We detected brain regions that showed correlation between AMPAR density and symptomatology scores in each of four disorders. We also found brain areas with significant differences in AMPAR density between patients with each psychiatric disorder and healthy participants. Some of these areas were observed across diseases, indicating that these are commonly affected areas throughout psychiatric disorders. Schizophrenia, bipolar disorder, depression, and autism spectrum disorder are uniquely characterized by AMPAR distribution patterns. Our approach to psychiatric disorders using [11C]K-2 can elucidate the biological mechanisms across diseases and pave the way to develop novel diagnostics and therapeutics based on the synapse physiology.