TY - JOUR 
A1 - Sánchez Rodríguez, Irene
AU - Djebari, Souhail
AU - Temprano Carazo, Sara
AU - Vega Avelaira, David
AU - Jiménez Herrera, Raquel
AU - Iborra Lázaro, Guillermo
AU - Yajeya, Javier
AU - JIménez Díaz, Lidia
AU - Navarro López, Juan D.
T1 - Hippocampal long-term synaptic depression and memory deficits induced in early amyloidopathy are prevented by enhancing G-protein-gated inwardly-rectifying potassium channel activity
Y1 - 2020
SN - 0022-3042

UR - http://hdl.handle.net/11268/10482
AB - Hippocampal synaptic plasticity disruption by amyloid-β (Aβ) peptides + thought to be responsible for learning and memory impairments in Alzheimer's disease (AD) early stage. Failures in neuronal excitability maintenance seems to be an underlying mechanism. G-protein-gated inwardly rectifying potassium (GirK) channels control neural excitability by hyperpolarization in response to many G-protein-coupled receptors activation. Here, in early in vitro and in vivo amyloidosis mouse models, we study whether GirK channels take part of the hippocampal synaptic plasticity impairments generated by Aβ1-42 . In vitro electrophysiological recordings from slices showed that Aβ1-42 alters synaptic plasticity by switching high-frequency stimulation (HFS) induced long-term potentiation (LTP) to long-term depression (LTD), which led to in vivo hippocampal-dependent memory deficits. Remarkably, selective pharmacological activation of GirK channels with ML297 rescued both HFS-induced LTP and habituation memory from Aβ1-42 action. Moreover, when GirK channels were specifically blocked by Tertiapin-Q, their activation with ML297 failed to rescue LTP from the HFS-dependent LTD induced by Aβ1-42 . On the other hand, the molecular analysis of the recorded slices by western blot showed that the expression of GIRK1/2 subunits, which form the prototypical GirK channel in the hippocampus, was not significantly regulated by Aβ1-42 . However, immunohistochemical examination of our in vivo amyloidosis model showed Aβ1-42 to down-regulate hippocampal GIRK1 subunit expression. Together, our results describe an Aβ-mediated deleterious synaptic mechanism that modifies the induction threshold for hippocampal LTP/LTD and underlies memory alterations observed in amyloidosis models. In this scenario, GirK activation assures memory formation by preventing the transformation of HFS-induced LTP into LTD.
KW - Depresión
KW - Neuroquímica
KW - Memoria
KW - Investigación sobre el cerebro
LA - eng
ER -