Reward learning requires activity of matrix metalloproteinase-9 in the central amygdala

Knapska, Ewelina; Lioudyno, Victoria; Kiryk, Anna; Mikosz, Marta; Górkiewicz, Tomasz; Michaluk, Piotr; Gawlak, Maciej; Chaturvedi, Mayank; Mochol, Gabriela; Balcerzyk, Marcin; Wójcik, Daniel K.; Wilczynski, Grzegorz M.; Kaczmarek, Leszek

doi:http://dx.doi.org/10.1523/JNEUROSCI.5239-12.2013

Reward learning requires activity of matrix metalloproteinase-9 in the central amygdala

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Knapska E, Lioudyno V, Kiryk A, Mikosz M, Górkiewicz T, Michaluk P, Gawlak M, Chaturvedi M, Mochol G, Balcerzyk M, Wojcik DK, Wilczynski GM, Kaczmarek L. Reward learning requires activity of matrix metalloproteinase-9 in the central amygdala. J Neurosci. 2013;33(36):14591-600. DOI: 10.1523/JNEUROSCI.5239-12.2013

Abstract

Learning how to avoid danger and pursue reward depends on negative emotions motivating aversive learning and positive emotions motivating appetitive learning. The amygdala is a key component of the brain emotional system; however, an understanding of how various emotions are differentially processed in the amygdala has yet to be achieved.Wereport that matrix metalloproteinase-9 (MMP-9, extracellularly operating enzyme) in the central nucleus of the amygdala (CeA) is crucial for appetitive, but not for aversive, learning in mice. The knock-out of MMP-9 impairs appetitively motivated conditioning, but not an aversive one. MMP-9 is present at the excitatory synapses in the CeA with its activity greatly enhanced after the appetitive training. Finally, blocking extracellular MMP-9 activity with its inhibitor TIMP-1 provides evidence that local MMP-9 activity in the CeA is crucial for the appetitive, but not for aversive, learning.