Technetium(V) and rhenium(V) complexes for 5-HT2A serotonin receptor binding: structure-affinity considerations

Area of Science:

• Radiopharmaceutical Chemistry
• Medicinal Chemistry
• Molecular Imaging

Background:

• Ketanserin is a well-established serotonin (5-HT) antagonist.
• Development of novel receptor ligands is crucial for advancing molecular imaging and therapeutics.
• Serotonin receptors, particularly 5-HT2, are targets for various neurological and psychiatric conditions.

Purpose of the Study:

• To synthesize novel oxotechnetium(V) and oxorhenium(V) complexes.
• To design compounds that mimic organic 5-HT2 receptor ligands by incorporating ketanserin fragments.
• To evaluate the receptor-binding affinity of the synthesized complexes.

Main Methods:

• Synthesis of neutral [MOL1L2] complexes (M = Tc, Re) using Tc(V) or Re(V) precursors.
• Combination of tridentate ligands (L1) and monodentate thiolates (L2) bearing ketanserin fragments.
• Receptor-binding assays using [3H]ketanserin to determine IC50 values.

Main Results:

• Successfully synthesized novel oxotechnetium(V) and oxorhenium(V) complexes.
• The lipophilic complexes demonstrated significant inhibition of specific [3H]ketan-serin binding.
• IC50 values for the inhibition ranged from 10 to 50 nM, indicating high affinity.

Conclusions:

• The synthesized technetium and rhenium complexes show promise as potential serotonin receptor ligands.
• These complexes can effectively compete with known serotonin antagonists in receptor-binding assays.
• The study provides a foundation for developing new radiotracers or therapeutic agents targeting serotonin receptors.