The effect of aging-associated impaired mitochondrial status on kainate-evoked hippocampal gamma oscillations.

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Abstract

Oscillations in hippocampal neuronal networks in the gamma frequency band have been implicated in various cognitive tasks and we showed previously that aging reduces the power of such oscillations. Here, using submerged hippocampal slices allowing simultaneous electrophysiological recordings and imaging, we studied the correlation between the kainate-evoked gamma oscillation and mitochondrial activity, as monitored by rhodamine 123. We show that the initiation of kainate-evoked gamma oscillations induces mitochondrial depolarization, indicating a metabolic response. Aging had an opposite effect on these parameters: while depressing the gamma oscillation strength, it increases mitochondrial depolarization. Also, in the aged neurons, kainate induced significantly larger Ca(2+) signals. In younger slices, acute mitochondrial depolarization induced by low concentrations of mitochondrial protonophores strongly, but reversibly, inhibits gamma oscillations. These data indicating that the complex network activity required by the maintenance of gamma activity is susceptible to changes and modulations in mitochondrial status.

Details

Original languageEnglish
Pages (from-to)2692–2703
JournalNeurobiology of Aging
Volume33
Issue number11
Publication statusPublished - Nov 2012

Keywords

  • Gamma oscillations, Kainate, Mitochondrial depolarization, Calcium signal, Mitochondrial protonophore