title: The Neuroprotective Effect of Lithium in cannabinoid Dependence is Mediated through Modulation of Cyclic AMP, ERK1/2 and GSK-3β Phosphorylation in Cerebellar Granular Neurons of Rat.
abstract: Lithium (Li), a glycogen synthase kinase-3β (GSK-3β) inhibitor, has used to attenuate the cannabinoid-induced dependence/withdrawal signs, but molecular mechanisms related to this are unclear. Recent studies indicate the involvement of upstream extracellular signal kinase1/2 (ERK1/2) and downstream GSK-3β pathways in the development of cannabinoid-induced dependence. This is mediated through cannabinoid receptor 1 (CB1) enriched in cerebellar granular neurons (CGNs). Accordingly, the present study aimed to investigate the mechanism of modulatory/neuroprotective effects of Li on a cannabinoid agonist (WIN 55,212-2 (WIN))-induced dependence, through quantitative analysis of some involved proteins such as ERK1/2, GSK-3β and related signaling pathways including their phosphorylated forms; and cAMP level as the other molecular mechanisms leading to dependence, in CGNs model. The CGNs were prepared from 7-day-old Wistar rat pup in a 12-well plate, pretreated with Li (1mM) and an ERK1/2 inhibitor SL327 (SL, 10 µM). The WIN (1 µM) was added 30 minutes prior to treatment and AM251 (AM, 1 µM), as a cannabinoid antagonist was co-treated with WIN. The cAMP level, as an indicator of cannabinoid-induced dependence, was measured by ELISA following forskolin (FSK) stimulation. Western blot analyses determined the phosphorylated forms of ERK1/2 (p-ERK1/2), GSK-3β (p-GSK-3β) as well as their total expressions in various treatment times and doses in CGNs. WIN alone could down regulate the cAMP/p-ERK1/2 cascade compared to AM treatment. However, P-GSK-3β was up-regulated with Li and WIN or with SL and Li pretreatment to AM-induced cellular response, which was the highest 60 minutes after CGNs exposure. Results further suggested the potential role of Li pretreatment to diminish the development of cannabinoid-induced dependence/neuronal injury through possible mechanisms of modulating the cAMP/p-ERK1/2 cascade independent of p-GSK-3β signaling pathway in-vitro.
authors.affiliation: Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran. ; PharmaceuticsResearch Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran. ; Department of Toxicology and Pharmacology, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Rahimi
authors.affiliation: Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Ghahremani
authors.affiliation: Experimental Medicine Research Center, Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences,Tehran, Iran.
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Dehpour
authors.affiliation: Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sharifzadeh
authors.affiliation: Experimental Medicine Research Center, Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences,Tehran, Iran.
authors.forename: Shahram
authors.initials: S
authors.lastname: Ejtemaei-Mehr
authors.affiliation: Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj,Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Razmi
authors.affiliation: Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyed Nasser
authors.initials: SN
authors.lastname: Ostad
keywords: 212-2; Cerebellar granular neurons; Cyclic AMP; Dependence; In-vitro; WIN 55