title: Inhibition of matrix metalloproteinases prevents the potentiation of nondeprived-eye responses after monocular deprivation in juvenile rats.
abstract: The ocular dominance (OD) shift induced by monocular deprivation (MD) during the critical period is mediated by an initial depression of deprived-eye responses followed by an increased responsiveness to the nondeprived eye. It is not fully clear to what extent these 2 events are correlated and which are their physiological and molecular mediators. The extracellular synaptic environment plays an important role in regulating visual cortical plasticity. Matrix metalloproteinases (MMPs) are a family of activity-dependent zinc-dependent extracellular endopeptidases mediating extracellular matrix remodeling. We investigated the effects of MMP inhibition on OD plasticity in juvenile monocularly deprived rats. By using electrophysiological recordings, we found that MMP inhibition selectively prevented the potentiation of neuronal responses to nondeprived-eye stimulation occurring after 7 days of MD and potentiation of deprived-eye responses occurring after eye reopening. Three days of MD only resulted in a depression of deprived-eye responses insensitive to MMP inhibition. MMP inhibition did not influence homeostatic plasticity tested in the monocular cortex but significantly prevented an increase in dendritic spine density present after 7 days MD in layer II-III pyramids.
authors.affiliation: Institute of Neuroscience, Consiglio Nazionale delle Ricerche, 56100 Pisa, Italy. m.spolidoro@sns.it
authors.forename: M
authors.initials: M
authors.lastname: Spolidoro
authors.forename: E
authors.initials: E
authors.lastname: Putignano
authors.forename: C
authors.initials: C
authors.lastname: Munafò
authors.forename: L
authors.initials: L
authors.lastname: Maffei
authors.forename: T
authors.initials: T
authors.lastname: Pizzorusso
mesh_terms: D020757:Amaurosis Fugax / Q000201:enzymology* / Q000503:physiopathology; D000818:Animals; D004151:Dipeptides / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005074:Evoked Potentials, Visual / Q000187:drug effects / Q000502:physiology*; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D051381:Rats; D020318:Rats, Long-Evans; D014793:Visual Cortex / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*
chemical_list: D004151:Dipeptides; D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D020782:Matrix Metalloproteinases