Vestibular Modulation of Long-Term Potentiation and NMDA Receptor Expression in the Hippocampus

Abstract

Loss of vestibular function is known to cause spatial memory deficits and hippocampal dysfunction, in terms of impaired place cell firing and abnormal theta rhythm. Based on these results, it has been of interest to determine whether vestibular loss also affects the development and maintenance of long-term potentiation (LTP) in the hippocampus. This article summarizes and critically reviews the studies of hippocampal LTP following a vestibular loss and its relationship to NMDA receptor expression, that have been published to date. Although the available in vitro studies indicate that unilateral vestibular loss (UVL) results in reduced hippocampal field potentials in CA1 and the dentate gyrus (DG), the in vivo studies involving bilateral vestibular loss (BVL) do not. This may be due to the differences between UVL and BVL or it could be a result of in vitro/in vivo differences. One in vitro study reported a decrease in LTP in hippocampal slices following UVL; however, the two available in vivo studies have reported different results: either no effect or an increase in EPSP/Population Spike (ES) potentiation. This discrepancy may be due to the different high-frequency stimulation (HFS) paradigms used to induce LTP. The increased ES potentiation following BVL may be related to an increase in synaptic NMDA receptors, possibly increasing the flow of vestibular input coming into CA1, with a loss of selectivity. This might cause increased excitability and synaptic noise, which might lead to a degradation of spatial learning and memory.

Electroacupuncture Reverses CUMS-Induced Depression-Like Behaviors and LTP Impairment in Hippocampus by Downregulating NR2B and CaMK II Expression

“…e hippocampus is an important target for the study of excitatory-dependent synaptic plasticity in the mammalian brain [36]. erefore, the current study of synaptic plasticity mainly focused on the hippocampus [37,38]. In this research, we also focused on the hippocampus to study the relationship between depression, synaptic plasticity, and EA treatment.…”

Vertigoheel improves central vestibular compensation after unilateral peripheral vestibulopathy in rats

“…There does not appear to be an effect of Vertigoheel on this parameter. The vestibulo-injured groups preferentially use egocentric strategy, i.e., somesthesia-centered since vestibular information is absent and likely impairs visuo-vestibular integration within the hippocampus and thus spatial memory (46)(47)(48). Vertigoheel does not improve the spatial memorybased strategy.…”

Applications of Multivariate Statistical and Data Mining Analyses to the Search for Biomarkers of Sensorineural Hearing Loss, Tinnitus, and Vestibular Dysfunction

“…One of our research interests has been the role of neurochemical changes in the hippocampus in the cognitive deficits that occur following peripheral bilateral vestibular damage. In this process we have used western blotting to analyse the expression of various glutamate receptor subtypes in the rat hippocampus, given the importance of glutamate receptors to memory processes such as long-term potentiation [see ( 71 ) for a review]. Due to the fact that we quantified 5 different glutamate receptor subunit subtypes (GluR1, GluR2, GluR3, NR1, and NR2) and 2 forms of calmodulin kinase II (CaMII and phosphorylated CaMII), related to glutamate receptor activation, we decided to use PCA and cluster analysis to analyse the results, particularly so that we could understand the co-variation and interactions of any changes in the expression of the proteins.…”