NMDA receptor subunits expression after habituation and synaptic plasticity induction.

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

Buenos Aires

Simposio; 2do Simposio Franco Argentino de Neurociencias; 2012

We investigated if major NMDAR subunits in the hippocampus of adult rats undergo similar changes driven by behavioral experience and synaptic plasticity induced by LTP in fresh slices. For this reason, GluN1, GluN2A and GluN2B were assessed in: 1) adult rats left to freely explore an open field for 5 minutes which led to habituation, 2) mature primary cultures of rat hippocampal neurons depolarized by pulses of KCl and 3) hippocampal fresh slices from adult rats, where LTP was induced by theta-burst stimulation. GluN1 and GluN2A, but not GluN2B in the rat hippocampus, undergo a conspicuous increase after habituation, compared to non-habituated controls, when assessed 70 minutes after 5 minutes open field exploration. This result strongly suggests that activity due to habituation might be responsible for the modifications, which occurred within about one hour after exposure to the new environment. Both GluN1 and GluN2A also increased in primary cultured neurons, as evaluated by total immunofluorescence 70 minutes after stimulation with repeated pulses of KCl. Moreover, there was a conspicuous increase in GluN1 and GluN2A immunofluoresce that was mainly localized in neurites. Similar changes occurred 70 minutes after LTP induction by theta burst stimulation hippocampal fresh slices of adult rats. To investigate what mechanisms: transcription and/or translation might underlie those modifications; hippocampal slices from adult rats were pretreated either with cycloheximide or actinomycin D. Our results showed that the increase in GluN2A subunit was dependent on translation, while the rise in GluN1 was dependent on transcription and translation mechanisms.