Signalling profile differences: paliperidone versus risperidone.

Area of Science:

• Pharmacology
• Neuroscience
• Molecular Biology

Background:

• Paliperidone, an active metabolite of risperidone, is approved for schizophrenia and schizoaffective disorder.
• The structural difference (a single hydroxyl group) between paliperidone and risperidone raises questions about their distinct pharmacological profiles.

Purpose of the Study:

• To compare the relative efficacies of paliperidone and risperidone.
• To investigate their regulation of cellular signaling pathways linked to key G protein-coupled receptors (GPCRs).

Main Methods:

• Compared paliperidone and risperidone efficacies on human dopamine D2, serotonin 5-HT2A, serotonin 5-HT2C, and histamine H1 receptors.
• Assessed regulation of associated cellular signaling pathways.

Main Results:

• Significant differences in receptor-signaling regulation were observed between paliperidone and risperidone.
• Both drugs acted as agonists in 5-HT2A-mediated beta-arrestin recruitment, 5-HT2A-mediated ERK sensitization, and dopamine D2-mediated adenylyl cyclase signaling.
• Relative efficacy varied depending on the specific receptor-response pair.

Conclusions:

• The hydroxyl group in paliperidone induces distinct receptor conformations compared to risperidone.
• These conformational differences lead to varied regulation of cellular signal transduction cascades.
• Cellular signaling disparities may translate to differences in clinical efficacy and adverse effect profiles.