title: Reward learning requires activity of matrix metalloproteinase-9 in the central amygdala.
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. We report 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.
authors.affiliation: Department of Neurophysiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland. e.knapska@nencki.gov.pl
authors.forename: Ewelina
authors.initials: E
authors.lastname: Knapska
authors.forename: Victoria
authors.initials: V
authors.lastname: Lioudyno
authors.forename: Anna
authors.initials: A
authors.lastname: Kiryk
authors.forename: Marta
authors.initials: M
authors.lastname: Mikosz
authors.forename: Tomasz
authors.initials: T
authors.lastname: Górkiewicz
authors.forename: Piotr
authors.initials: P
authors.lastname: Michaluk
authors.forename: Maciej
authors.initials: M
authors.lastname: Gawlak
authors.forename: Mayank
authors.initials: M
authors.lastname: Chaturvedi
authors.forename: Gabriela
authors.initials: G
authors.lastname: Mochol
authors.forename: Marcin
authors.initials: M
authors.lastname: Balcerzyk
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Wojcik
authors.forename: Grzegorz M
authors.initials: GM
authors.lastname: Wilczynski
authors.forename: Leszek
authors.initials: L
authors.lastname: Kaczmarek
mesh_terms: D000679:Amygdala / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001070:Appetitive Behavior; D003216:Conditioning, Operant; D020780:Matrix Metalloproteinase 9 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D012201:Reward; D013569:Synapses / Q000378:metabolism / Q000502:physiology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000494:pharmacology
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse