4. Discussion
We have investigated whether expression of ArcKR, a form of Arc where
the major ubiquitination sites have been mutated, and its degradation is
slowed, (Mabb et al. , 2014;
Wall et al. , 2018) affects
synaptic plasticity in area CA1 of the hippocampus. In particular, we
have investigated the effects of ArcKR expression on long-term
potentiation (LTP) and whether priming of mGluR affects LTP in this
mouse. In agreement with our previous study
(Wall et al. , 2018), we found that
SC-CA1 basal synaptic transmission was not significantly different in
standard housed adult ArcKR mice compared to WT mice. We also showed
that, like DHPG-induced- LTD (Wallet al. , 2018), synaptically-induced paired-pulse low frequency
stimulation (PP-LFS)-induced mGluR-LTD was significantly enhanced in
ArcKR mice. Corroborating the idea that transient increase in Arc
expression levels facilitate PP-LFS-mediated LTD is the observation that
Arc mRNA and protein expression, as well as PP-LFS mediated LTD are
increased in the hippocampus in the APP/PS1 mouse at 7 months of age
(Privitera et al. , 2022).