Medical Neurobiology Commons^™

Substrate And Regulation Of Mitochondrial Μ-Calpain, Aashish Joshi

University of Kentucky Doctoral Dissertations

μ -Calpain is localized to the mitochondrial intermembrane space. Apoptosisinducing factor (AIF), which executes caspase-independent cell death, is also localized to the mitochondrial intermembrane space. Following processing at the N-terminus, AIF becomes truncated (tAIF) and is released from mitochondria. The protease responsible for AIF processing has not been established. The same submitochondrial localization of mitochondrial μ-calpain and AIF gives support to the hypothesis that mitochondrial μ-calpain may be responsible for processing AIF. Atractyloside-induced tAIF release in rat liver mitochondria was inhibited by cysteine protease inhibitor MDL28170, but not by calpain inhibitors PD150606 or calpastatin. Moreover, μ-calpain immunoreactivity was difficult to …

Role Of Cyclophilin D In Secondary Spinal Cord And Brain Injury, Jordan Mills Clark

University of Kentucky Doctoral Dissertations

In the hours and days following acute CNS injury, a secondary wave of events is initiated that exacerbate spinal tissue damage and neuronal cell death. A potential mechanism driving these secondary events is opening of the mitochondrial permeability transition pore (mPTP) and subsequent release of several cell death proteins. Previous studies have shown that inhibition of cyclophilin D(CypD), the key regulating component in mPTP opening, was protective against insults that induce necrotic cell death. We therefore hypothesized that CypD-null mice would show improved functional and pathological outcomes following spinal cord injury (SCI) and traumatic brain injury (TBI). Moderate and severe …

Glutamate Regulation In The Hippocampal Trisynaptic Pathway In Aging And Status Epilepticus, Michelle Lee Stephens

University of Kentucky Doctoral Dissertations

A positive correlation exists between increasing age and the incidence of hippocampal-associated dysfunction and disease. Normal L-glutamate neurotransmission is absolutely critical for hippocampal function, while abnormal glutamate neurotransmission has been implicated in many neurodegenerative diseases. Previous studies, overwhelmingly utilizing ex vivo methods, have filled the literature with contradicting reports about hippocampal glutamate regulation during aging. For our studies, enzyme-based ceramic microelectrode arrays (MEA) were used for rapid (2 Hz) measurements of extracellular glutamate in the hippocampal trisynaptic pathway of young (3-6 months), late-middle aged (18 mo.) and aged (24 mo.) urethane-anesthetized Fischer 344 rats. Compared to young animals, glutamate terminals …

Age May Be Hazardous To Outcome Following Traumatic Brain Injury: The Mitochondrial Connection, Lesley Knight Gilmer

University of Kentucky Doctoral Dissertations

Older individuals sustaining traumatic brain injury (TBI) experience a much higher incidence of morbidity and mortality. This age-related exacerbated response to neurological insult has been demonstrated experimentally in aged animals, which can serve as a model to combat this devastating clinical problem. The reasons for this worse initial response are unknown but may be related to age-related changes in mitochondrial respiration.

Evidence is shown that mitochondrial dysfunction occurs early following traumatic brain injury (TBI), persists long after the initial insult, and is severitydependent. Synaptic and extrasynaptic mitochondrial fractions display distinct respiration capacities, stressing the importance to analyze these fractions separately. …