VM Pogorelov, RM Rodriguiz, J Cheng, M Huang, CM Schmerberg, HY Meltzer, BL Roth, AP Kozikowski and WC Wetsel,
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, Mar 2017 15
All FDA-approved antipsychotic drugs (APDs) target primarily dopamine D2 or serotonin (5-HT2A) receptors, or both; however, these medications are not universally effective, they may produce undesirable side-effects, and provide only partial amelioration of negative and cognitive symptoms. The heterogeneity of pharmacological responses in schizophrenic patients suggests additional drug-targets may be effective in improving aspects of this syndrome. Recent evidence suggests that 5-HT2C receptors may be a promising target for schizophrenia since their activation reduces mesolimbic nigrostriatal dopamine release (which conveys antipsychotic action), they are expressed almost exclusively in CNS, and have weight-loss promoting capabilities. A difficulty in developing 5-HT2C agonists is that most ligands possess also 5-HT2B and/or 5-HT2A activities. We have developed selective 5-HT2C ligands and herein describe their preclinical effectiveness for treating schizophrenia-like behaviors. JJ-3-45, JJ-3-42, and JJ-5-34 reduced amphetamine-stimulated hyperlocomotion, restored amphetamine-disrupted prepulse inhibition, improved social behavior and novel object recognition memory in NMDA receptor hypofunctioning NR1-knockdown mice, and were essentially devoid of catalepsy. However, they decreased motivation in a breakpoint assay and did not promote reversal learning in MK-801-treated mice. Somewhat similar effects were observed with lorcaserin, a 5-HT2C agonist with potent 5-HT2B and 5-HT2A agonist activities, which is approved for treating obesity. Microdialysis studies revealed that both JJ-3-42 and lorcaserin reduced dopamine efflux in the infralimbic cortex, while only JJ-3-42 decreased it in striatum. Collectively, these results provide additional evidence that 5-HT2C receptors are suitable drug-targets with fewer side effects, greater therapeutic selectivity, and enhanced efficacy for treating schizophrenia and related disorders than current APDs.Neuropsychopharmacology accepted article preview online, 15 March 2017. doi:10.1038/npp.2017.52.