Masilamoni Gunasingh J, Uthayathas Subramanian, Koenig Gerhard, Leventhal Liza, Papa Stella M
Yerkes National Primate Research Center, Emory University School of Medicine, Atlanta, GA, USA.
Research, FORUM Pharmaceuticals Inc., 225 Second Avenue, Waltham, MA, USA.
Neuropharmacology. 2016 Nov;110(Pt A):449-457. doi: 10.1016/j.neuropharm.2016.08.012. Epub 2016 Aug 15.
Schizophrenia symptoms are associated with alterations in basal ganglia-cortical networks that include the cyclic nucleotides (cAMP/cGMP) signaling pathways. Phosphodiesterase 10A (PDE10A) inhibitors have been considered as therapeutic agents for schizophrenia because the regulation of cAMP and cGMP in the striatum by PDE10A plays an important role in the signaling mechanisms of the striatal-cortical network, and thereby in cognitive function. In the present study we assessed in non-human primates (NHPs) the effects of a novel PDE10A inhibitor (FRM-6308) that has demonstrated high potency and selectivity for human recombinant PDE10A in vitro. The behavioral effects of FRM-6308 in a dose range were determined in rhesus monkeys using a standardized motor disability scale for primates, motor tasks, and the "drug effects on the nervous system" (DENS) scale. The neuronal metabolic effects of FRM-6308 were determined with [(18)F]-fluorodeoxyglucose PET imaging. Results showed that FRM-6308 did not have any specific effects on the motor system at s.c. doses up to 0.32 mg/kg in NHPs, which induced a significant increase in the FDG-SUV in striatum (F 16.069, p < 0.05) and cortical (F 15.181, p < 0.05) regions. Higher doses induced sedation and occasional involuntary movements with clear development of tolerance after repeated exposures. These findings suggest that FRM-6308 has the adequate pharmacological profile to advance testing in clinical trials and demonstrate antipsychotic efficacy of PDE10A inhibition for the treatment of schizophrenia patients.
精神分裂症症状与基底神经节 - 皮质网络的改变有关,该网络包括环核苷酸(cAMP/cGMP)信号通路。磷酸二酯酶10A(PDE10A)抑制剂被认为是治疗精神分裂症的药物,因为PDE10A对纹状体中cAMP和cGMP的调节在纹状体 - 皮质网络的信号传导机制中起重要作用,进而在认知功能中起重要作用。在本研究中,我们在非人类灵长类动物(NHP)中评估了一种新型PDE10A抑制剂(FRM - 6308)的效果,该抑制剂在体外对人重组PDE10A已显示出高效力和选择性。使用灵长类动物标准化运动残疾量表、运动任务以及“药物对神经系统的影响”(DENS)量表,在恒河猴中确定了FRM - 6308在一定剂量范围内的行为效应。用[(18)F] - 氟脱氧葡萄糖PET成像确定了FRM - 6308的神经元代谢效应。结果表明,在NHP中,皮下注射剂量高达0.32 mg/kg时,FRM - 6308对运动系统没有任何特异性影响,这导致纹状体(F 16.069,p < 0.05)和皮质区域(F 15.181,p < 0.05)的FDG - SUV显著增加。更高剂量会引起镇静作用,并且在重复给药后偶尔会出现不自主运动,且明显产生耐受性。这些发现表明,FRM - 6308具有足够的药理学特征,可推进临床试验测试,并证明PDE10A抑制对精神分裂症患者的抗精神病疗效。