title: Differential effects of glycogen synthase kinase 3 (GSK3) inhibition by lithium or selective inhibitors in the central nervous system.
abstract: Glycogen synthase kinase (GSK3) is a constitutively active serine-threonine kinase associated to neurological and psychiatric disorders. GSK3 inhibition is considered a mediator of the efficacy of the mood-stabiliser lithium. This study aimed at comparing the central nervous system effect of lithium with the selective GSK3 inhibitors AZ1080 and compound A in biochemical, cellular, and behavioural tests. Collapsin response mediator protein 2 is a neuron-specific GSK3 substrate. Lithium, AZ1080, and compound A inhibited its phosphorylation in rat primary neurons with different pIC50. After systemic treatments with lithium or GSK3 inhibitors to assess specific functional responses, phosphorylation was unchanged in adult rat brain, while it was strongly inhibited by GSK3 inhibitors in pups, differently from lithium. Lithium may exert neurotrophic effect by increasing brain-derived neurotrophic factor (BDNF) levels: in the present experimental conditions, lithium exerted opposite effects on plasma BDNF levels compared to GSK3 inhibitors, suggesting this effect might not be necessarily mediated by GSK3 inhibition alone. While plasma thyroid-stimulating hormone and luteinising hormone were not affected by lithium, they were decreased by selective inhibitors. GH and prolactin displayed similar responses towards reduction. Follicle-stimulating hormone levels were not altered by treatments, whereas melatonin was specifically increased by AZ1080. Lithium impaired mouse spontaneous locomotion and decreased amphetamine-induced hyper-locomotion. AZ1080 had no effects on locomotion, while compound A reduced spontaneous locomotor activity without effects on amphetamine-induced hyper-locomotion. The present results indicate that a broad correlation between the effects of lithium and selective GSK3 inhibitors could not be devised, suggesting alternative mechanisms, whereas overlapping results could be obtained in specific assays.
authors.affiliation: Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Via Fleming, 4, 37135, Verona, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Caberlotto
authors.forename: Lucia
authors.initials: L
authors.lastname: Carboni
authors.forename: Floriana
authors.initials: F
authors.lastname: Zanderigo
authors.forename: Filippo
authors.initials: F
authors.lastname: Andreetta
authors.forename: Michela
authors.initials: M
authors.lastname: Andreoli
authors.forename: Gabriella
authors.initials: G
authors.lastname: Gentile
authors.forename: Maria
authors.initials: M
authors.lastname: Razzoli
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D005746:Gastric Emptying / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors*; D006728:Hormones / Q000097:blood; D036341:Intercellular Signaling Peptides and Proteins; D018020:Lithium Compounds / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D006728:Hormones; D036341:Intercellular Signaling Peptides and Proteins; D018020:Lithium Compounds; D009419:Nerve Tissue Proteins; D047428:Protein Kinase Inhibitors; C095114:collapsin response mediator protein-2; D038362:Glycogen Synthase Kinase 3