Paliperidone (9-hydroxyrisperidone) is a dopamine antagonist of the atypical antipsychotic class of medications. IC50 value:Target: dopamine receptorin vitro: Paliperidone inhibited MK-801 induced neurotoxicity both in MTT metabolism assay (p<0.01) and in lactate dehydrogenase (LDH) activity assay (p<0.01). Moreover, paliperidone could significantly retard MK-801-mediated inhibition of neurite outgrowth (p<0.01) and reverse MK-801-induced decreases of gene expression and phosphorylation of Akt1 and GSK3β (both p<0.01). Furthermore, these protective effects of paliperidone were blocked by pretreatment with a PI3K inhibitor LY294002 [1]. paliperidone works finely at low concentrations (10 and 50 μM) against Aβ(25-35) and MPP(+) and solely protected SH-SY5Y from hydrogen peroxide. At 100 μM, paliperidone completely diminished cell reduction induced by different stressors, regardless of their dosages. Paliperidone was demonstrated with a higher oxidative stress-scavenging properties than other APDs in several aspects, such as generated bulk glutathione, low HNE, and protein carbonyl productions [2].in vivo: The 9OHRIS (4 mg/bwkg) was administred by gastric tube. Four groups were formed depending on the treatment: (1) control, (2) stress, (3) 9OHRIS, (4) stress and parallel 9OHRIS treatment (n=5-6). The expression of APP, MAPK1, β-actin mRNAs from the perfused brain samples was measured with real-time PCR technique [3].Male offspring were treated orally via drinking water with vehicle, risperidone (0.01mg/kg/day), or paliperidone (0.01mg/kg/day) between postnatal days 35 and 56 (periadolescence) and extracellular glutamate levels in the prefrontal cortex were determined by microdialysis at PD 56 [4].

References:
[1]. Peng L, et al. Paliperidone protects prefrontal cortical neurons from damages caused by MK-801 via Akt1/GSK3β signaling pathway. Schizophr Res. 2013 Jun;147(1):14-23.
[2]. Yang MC, et al. Neuroprotection of paliperidone on SH-SY5Y cells against β-amyloid peptide(25-35), N-methyl-4-phenylpyridinium ion, and hydrogen peroxide-induced cell death. Psychopharmacology (Berl). 2011 Oct;217(3):397-410.
[3]. Kalman S, et al. 9-hydroxy-risperidone (9OHRIS) prevents stress-induced β-actin overexpression in rat hippocampus. Neuropsychopharmacol Hung. 2010 Sep;12(3):425-31.