title: Early activation of extracellular signal-regulated kinase signaling pathway in the hippocampus is required for short-term memory formation of a fear-motivated learning.
abstract: 1. According to its duration there are, at least, two major forms of memory in mammals: short term memory (STM) which develops in a few seconds and lasts several hours and long-term memory (LTM) lasting days, weeks and even a lifetime. In contrast to LTM, very little is known about the neural, cellular and molecular requirements for mammalian STM formation. 2. Here we show that early activation of extracellular signal-regulated kinases 1/2 (ERK1/2) in the hippocampus is required for the establishment of STM for a one-trial inhibitory avoidance task in the rat. Immediate posttraining infusion of U0126 (a selective inhibitor of ERK kinase) into the CA1 region of the dorsal hippocampus blocked STM formation. 3. Reversible inactivation of the entorhinal cortex through muscimol infusion produced deficits in STM and a selective and rapid decrease in hippocampal ERK2 activation.4. Together with our previous findings showing a rapid decrease in ERK2 activation and impaired STM after blocking BDNF function, the present results strongly suggest that ERK2 signaling in the hippocampus is a critical step in STM processing.
authors.affiliation: Instituto de Biología Celular y Neurociencias, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 3, 1121, Buenos Aires, Argentina.
authors.forename: Lionel Müller
authors.initials: LM
authors.lastname: Igaz
authors.forename: Milena
authors.initials: M
authors.lastname: Winograd
authors.forename: Martín
authors.initials: M
authors.lastname: Cammarota
authors.forename: Luciana A
authors.initials: LA
authors.lastname: Izquierdo
authors.forename: Mariana
authors.initials: M
authors.lastname: Alonso
authors.forename: Iván
authors.initials: I
authors.lastname: Izquierdo
authors.forename: Jorge H
authors.initials: JH
authors.lastname: Medina
mesh_terms: D000818:Animals; D001245:Association Learning; D005239:Fear / Q000523:psychology; D006624:Hippocampus / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000502:physiology; D008954:Models, Biological; D051381:Rats; D017208:Rats, Wistar
chemical_list: D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3