[alpha]CaMKII controls the establishment of cocaine's reinforcing effects in mice and humans

• Published in: Translational psychiatry Vol. 4; p. e457
• Main Authors: Easton, A C, Lourdusamy, A, Havranek, M, Mizuno, K, Solati, J, Golub, Y, Clarke, T-k, Vallada, H, Laranjeira, R, Desrivières, S, Moll, G H, Mössner, R, Kornhuber, J, Schumann, G, Giese, K P, Fernandes, C, Quednow, B B, Müller, C P
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01-10-2014
• ISSN: 2158-3188
• DOI: 10.1038/tp.2014.97

Although addiction develops in a considerable number of regular cocaine users, molecular risk factors for cocaine dependence are still unknown. It was proposed that establishing drug use and memory formation might share molecular and anatomical pathways. Alpha-Ca 2+ /calmodulin-dependent protein kinase-II (αCaMKII) is a key mediator of learning and memory also involved in drug-related plasticity. The autophosphorylation of αCaMKII was shown to accelerate learning. Thus, we investigated the role of αCaMKII autophosphorylation in the time course of establishing cocaine use-related behavior in mice. We found that αCaMKII autophosphorylation-deficient αCaMKII T286A mice show delayed establishment of conditioned place preference, but no changes in acute behavioral activation, sensitization or conditioned hyperlocomotion to cocaine (20 mg kg-1 , intraperitoneal). In vivo microdialysis revealed that αCaMKIIT286A mice have blunted dopamine (DA) and blocked serotonin (5-HT) responses in the nucleus accumbens (NAcc) and prefrontal cortex after acute cocaine administration (20 mg kg-1 , intraperitoneal), whereas noradrenaline responses were preserved. Under cocaine, the attenuated DA and 5-HT activation in αCaMKIIT286A mice was followed by impaired c-Fos activation in the NAcc. To translate the rodent findings to human conditions, several CAMK2A gene polymorphisms were tested regarding their risk for a fast establishment of cocaine dependence in two independent samples of regular cocaine users from Brazil (n=688) and Switzerland (n=141). A meta-analysis across both samples confirmed that CAMK2A rs3776823 TT-allele carriers display a faster transition to severe cocaine use than C-allele carriers. Together, these data suggest that αCaMKII controls the speed for the establishment of cocaine's reinforcing effects.