Bivalent dopamine D2 receptor ligands: synthesis and binding properties.

Area of Science:

• Neuroscience
• Pharmacology
• Medicinal Chemistry

Background:

• Dopamine D2 receptor homodimers are implicated in schizophrenia pathophysiology.
• Targeting GPCR dimerization is a promising avenue for atypical antipsychotic drug discovery.
• Bivalent ligands can serve as molecular probes to investigate and control receptor dimerization.

Purpose of the Study:

• To synthesize novel bivalent dopamine D2 receptor ligands.
• To investigate the binding mode and potential of these ligands in targeting receptor dimers.
• To explore their utility in the discovery of atypical antipsychotics.

Main Methods:

• Synthesis of bivalent ligands incorporating 1,4-disubstituted aromatic piperidines/piperazines (1,4-DAPs) and triazolyl-linked spacers.
• Radioligand binding studies to assess ligand affinity and binding characteristics.
• Comparative analysis with monovalent and unsymmetrical analogues to confirm bivalent binding.

Main Results:

• Successful synthesis of type 1 bivalent dopamine D2 receptor ligands.
• Radioligand binding studies indicated a bivalent binding mode for ligands with specific spacer lengths.
• Hill slopes close to two supported simultaneous occupancy of adjacent binding sites.

Conclusions:

• Bivalent ligands with specific spacer lengths effectively bind to dopamine D2 receptor dimers.
• This study validates the use of bivalent ligands as molecular probes for GPCR dimerization.
• The developed ligands represent a promising foundation for novel atypical antipsychotic drug discovery targeting schizophrenia.