Discovery and characterization of benzyloxy piperidine based dopamine 4 receptor antagonists

The dopamine receptor 4 (D4R) is highly expressed in both motor, associative and limbic subdivisions of the coritico-basal ganglia network. Due to the distribution in the brain, there is mounting evidence pointing to a role for the D4R in the modulation of this network and its subsequent involvement in L-DOPA induced dyskinesias in Parkinson’s disease. As part of our continued effort in the discovery of novel D4R antagonists, we report the discovery and characterization of a new 3- or 4-benzyloxypiperidine scaffold as D4R antagonists. We report several D4R selective compounds (>30-fold vs. other dopamine receptor subtypes) with improved in vitro and in vivo stability over previously reported D4R antagonists.

Dopamine receptor subtypes and incentive learning

Dopamine receptor subtypes and incentive learning explains that dopamine receptors are G protein-coupled and form two families: D1-like receptors, including D1 and D5, stimulate adenylyl cyclase and cyclic adenosine monophosphate (cAMP); D2-like receptors, including D2, D3, and D4, inhibit cAMP. Antipsychotic medications are dopamine receptor antagonists and their clinical potency is strongly correlated with blockade of D2 receptors, implicating overactivity of D2 receptors in psychosis in schizophrenia. D1- and D2-like receptors appear to be involved in unconditioned locomotor activity and incentive learning. D1-like receptors are implicated more strongly in incentive learning and D2-like receptors more strongly in locomotion. D3 receptors may play a relatively greater role in expression than acquisition of incentive learning. Dopamine receptor subtypes form heteromers with each other and with the receptors of other neurotransmitters (e.g., glutamate, adenosine, ghrelin) and the signaling properties of these heteromers can differ from those of either receptor in isolation.

Drugs for psychosis and mood: unique actions at D3, D2, and D1 dopamine receptor subtypes

Drugs for psychosis and mood that bind dopamine D2 receptors can be classified not only by whether they also block serotonin 2A receptors, but by whether they also bind D3 or D1 receptors.