A multivariate analysis of the effects of aging on glutamate, GABA and arginine metabolites in the rat vestibular nucleus

Liu, Ping; Zhang, Hu; Devaraj, Renuka; Ganesalingam, Ganes S.; Smith, Paul F.

doi:10.1016/j.heares.2010.06.019

Cited by 27 publications

(23 citation statements)

References 75 publications

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“…In the Brandt et al (2005) study, the patients were between 5 and 10 years post-BVD, whereas in the current rat study, the animals were at 16 months post-BVD. It is difficult to compare the life spans of rats and humans, but considering that 24 months of age is regarded as “aged” for a rat (Liu et al, 2010), 16 months of age is equivalent to a long-term time point. Given that the humans and rats both exhibited spatial memory deficits and were at long time intervals following BVD, the difference in time post-op.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Bilateral Vestibular Loss on Hippocampal Volume, Neuronal Number, and Cell Proliferation in Rats

Zheng¹,

Balabhadrapatruni²,

Baek³

et al. 2012

Front. Neur.

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Previous studies in humans have shown that bilateral loss of vestibular function is associated with a significant bilateral atrophy of the hippocampus, which correlated with the patients’ spatial memory deficits. More recently, patients who had recovered from unilateral vestibular neuritis have been reported to exhibit a significant atrophy of the left posterior hippocampus. Therefore, we investigated whether bilateral vestibular deafferentation (BVD) would result in a decrease in neuronal number or volume in the rat hippocampus, using stereological methods. At 16 months post-BVD, we found no significant differences in hippocampal neuronal number or volume compared to sham controls, despite the fact that these animals exhibited severe spatial memory deficits. By contrast, using bromodeoxyuridine (BrdU) as a marker of cell proliferation, we found that the number of BrdU-labeled cells significantly increased in the dentate gyrus of the hippocampus between 48 h and 1 week following BVD. Although a substantial proportion of these cells survived for up to 1 month, the survival rate was significantly lower in BVD animals when compared with that in sham animals. These results suggest a dissociation between the effects of BVD on spatial memory and hippocampal structure in rats and humans, which cannot be explained by an injury-induced increase in cell proliferation.

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Section: Discussionmentioning

confidence: 99%

The Effects of Bilateral Vestibular Loss on Hippocampal Volume, Neuronal Number, and Cell Proliferation in Rats

Zheng¹,

Balabhadrapatruni²,

Baek³

et al. 2012

Front. Neur.

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“…Age-related neuronal loss in the vestibular nucleus has been reported in both humans (Lopez et al, 1997) and mice (Sturrock, 1989). The vestibular nuclei of aged rats also show a number of abnormal structural changes (Johnson and Miquel, 1974) as well as reduced levels of glutamate which could indicate a reduction in excitatory afferent drive (Liu et al, 2010). Given that vestibular signals convey information about translation and rotation of the body, age-related changes of vestibular functioning will render self-motion perception imprecise.…”

Section: How Does Aging Affect Our Ability To Compute Online Spatimentioning

confidence: 99%

The Aging Navigational System

Lester

Moffat

Wiener

et al. 2017

Neuron

311

280

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“…Him et al ( 68 ) reported that the responses of MVN neurons to NMDA and AMPA were similar in brainstem slices from young (3 months of age) and aged rats (24 months of age), suggesting no change in the sensitivity of these glutamate receptor subtypes. Liu et al ( 69 ) compared glutamate levels in the VNCs of rats at 4 and 24 months of age, using homogenized samples and HPLC, and found that glutamate levels significantly decreased with age (see Figure 1 A); by contrast, there was no such decrease in the cerebellum. Since Him et al ( 68 ) measured only the response of MVN neurons to NMDA and AMPA, and Liu et al ( 69 ) measured only the levels of glutamate, the results of these two studies are not necessarily incompatible.…”

Section: Neurochemical Changes In the Vestibular Nucleus With Agementioning

confidence: 99%

“…Liu et al ( 69 ) compared glutamate levels in the VNCs of rats at 4 and 24 months of age, using homogenized samples and HPLC, and found that glutamate levels significantly decreased with age (see Figure 1 A); by contrast, there was no such decrease in the cerebellum. Since Him et al ( 68 ) measured only the response of MVN neurons to NMDA and AMPA, and Liu et al ( 69 ) measured only the levels of glutamate, the results of these two studies are not necessarily incompatible. For example, it is possible that AMPA and NMDA receptors upregulated or increased their sensitivity to glutamate in response to a decrease in its availability, resulting in an approximately normal response to those agonists.…”

Section: Neurochemical Changes In the Vestibular Nucleus With Agementioning

confidence: 99%

Age-Related Neurochemical Changes in the Vestibular Nuclei

Smith

2016

Front. Neurol.

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There is evidence that the normal aging process is associated with impaired vestibulo-ocular reflexes (VOR) and vestibulo-spinal reflexes, causing reduced visual acuity and postural instability. Nonetheless, the available evidence is not entirely consistent, especially with respect to the VOR. Some recent studies have reported that VOR gain can be intact even above 80 years of age. Similarly, although there is evidence for age-related hair cell loss and neuronal loss in Scarpa’s ganglion and the vestibular nucleus complex (VNC), it is not entirely consistent. Whatever structural and functional changes occur in the VNC as a result of aging, either to cause vestibular impairment or to compensate for it, neurochemical changes must underlie them. However, the neurochemical changes that occur in the VNC with aging are poorly understood because the available literature is very limited. This review summarizes and critically evaluates the available evidence relating to the noradrenaline, serotonin, dopamine, glutamate, GABA, glycine, and nitric oxide neurotransmitter systems in the aging VNC. It is concluded that, at present, it is difficult, if not impossible, to relate the neurochemical changes observed to the function of specific VNC neurons and whether the observed changes are the cause of a functional deficit in the VNC or an effect of it. A better understanding of the neurochemical changes that occur during aging may be important for the development of potential drug treatments for age-related vestibular disorders. However, this will require the use of more sophisticated methodology such as in vivo microdialysis with single neuron recording and perhaps new technologies such as optogenetics.

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A multivariate analysis of the effects of aging on glutamate, GABA and arginine metabolites in the rat vestibular nucleus

Cited by 27 publications

References 75 publications

The Effects of Bilateral Vestibular Loss on Hippocampal Volume, Neuronal Number, and Cell Proliferation in Rats

The Effects of Bilateral Vestibular Loss on Hippocampal Volume, Neuronal Number, and Cell Proliferation in Rats

The Aging Navigational System

Age-Related Neurochemical Changes in the Vestibular Nuclei

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