Selectivity and displaceability of specific binding |
– 100:1 greater affinity for 5-HT2A receptors over 5-HT2C receptors, and a 1:10 to 1:50 greater affinity of 5-HT2A receptors over D2 receptors.111 Since D2 receptors are 10-fold less dense in human cortex82–84,112 the combined relative effects of affinity and density correspond to an estimate that at least 99% of the specific binding signal in cortex is attributable to 5-HT2A receptors. – No effect of the D2 antagonist amisulpride on [18F] setoperone binding in human cortex113 – 5-HT2 antagonists fully block specific binding in animal and human cortex106,107,114,115 – Not selective in striatum where D2 receptor density is high107
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Reversibility | Very good with peak in cortex between 10 and 30 min107,110 |
Brain uptake | High106,107,109 |
Specific binding to free and nonspecific binding ratio | Very good; binding potential approximately 2 to 3 in age range18–40 yr89,107,110 |
Reliability of 5-HT2A BP | Excellent116 |
Metabolites | Radioactive metabolites unable to cross blood–brain barrier117 |