NMDA receptor subunits expression in the hippocampus after habituation to a new environment and synaptic plasticity induction

BAEZ MV; OBERHOLZER MV; CERCATO MC; SNITCOFSKY M; AGUIRRE AI; JERUSALINSKY DA

Cancún

Congreso; I Congreso de la Federación de Asociaciones Latinoamericanas y del Caribe de Neurociencias (FALAN).; 2012

Federación de Asociaciones Latinoamericanas y del Caribe de Neurociencias (FALAN)

N-methyl-D-aspartate (NMDA) receptor (NMDAR) subunits change during development and their expression at the surface is modified shortly after synaptic plasticity induction at hippocampal slices. However, there is scarce information on subunits expression after synaptic plasticity induction or memory acquisition, particularly on adult rats. In this work, GluN1, GluN2A and GluN2B were assessed by westernblot in 1) adult rats exposed to a 5 min open field (OF) session that gives rise to habituation, 2) mature primary cultures of rat hippocampal neurons depolarized by KCl pulses and 3) hippocampal slices from adult rats where long term potentiation (LTP) was induced by theta-burst stimulation (TBS). Hippocampal GluN1 and GluN2A, but not GluN2B underwent conspicuous increases after habituation, as assessed 70 min after OF exploration. The same subunits increased in cultured neurons as evaluated by total immunofluorescence 70 min after KCl stimulation. Similar changes occurred 70 min after LTP induction by TBS in hippocampal slices. To investigate the underlying mechanisms in this subunits increase, hippocampal slices from adult rats were treated either with cycloheximide or actinomycin D during electrophysiological assays. Results showed that GluN2A increase was dependent on translation, while the rise in GluN1 was dependent on transcription and translation. In the three models analyzed, changes were selective, detected in the same units at equivalent times. This might suggest that an analogous phenomenon regulates NMDAR expression at the hippocampus after LTP induction and after habituation to a new environment.