Neuroscience and Neurobiology Commons^™

Maternal Separation Affects Dopamine Transporter Function In The Spontaneously Hypertensive Rat: An In Vivo Electrochemical Study, Jacqueline S. Womersley, Jennifer H. Hsieh, Lauriston A. Kellaway, Greg A. Gerhardt, Vivienne A. Russell

Neuroscience Faculty Publications

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder characterised by symptoms of inattention, impulsivity and hyperactivity. The spontaneously hypertensive rat (SHR) is a well-characterised model of this disorder and has been shown to exhibit dopamine dysregulation, one of the hypothesised causes of ADHD. Since stress experienced in the early stages of life can have long-lasting effects on behaviour, it was considered that early life stress may alter development of the dopaminergic system and thereby contribute to the behavioural characteristics of SHR. It was hypothesized that maternal separation would alter dopamine regulation by the transporter (DAT) in ways that distinguish SHR …

Functional Plasticity Of Central Trpv1 Receptors In Brainstem Dorsal Vagal Complex Circuits Of Streptozotocin-Treated Hyperglycemic Mice, Andrea Zsombok, Muthu D. Bhaskaran, Hong Gao, Andrei V. Derbenev, Bret N. Smith

Physiology Faculty Publications

Emerging data indicate that central neurons participate in diabetic processes by modulating autonomic output from neurons in the dorsal motor nucleus of the vagus (DMV). We tested the hypothesis that synaptic modulation by transient receptor potential vanilloid type 1 (TRPV1) receptors is reduced in the DMV in slices from a murine model of type 1 diabetes. The TRPV1 agonist capsaicin robustly enhanced glutamate release onto DMV neurons by acting at preterminal receptors in slices from intact mice, but failed to do so in slices from diabetic mice. TRPV1 receptor protein expression in the vagal complex was unaltered. Brief insulin preapplication …

A Model Of Intracellular Θ Phase Precession Dependent On Intrinsic Subthreshold Membrane Currents., L Stan Leung

Physiology and Pharmacology Publications

A hippocampal place cell fires at an increasingly earlier phase in relation to the extracellular theta rhythm as a rodent moves through the place field. The present report presents a compartment model of a CA1 pyramidal cell that explains the increase in amplitude and the phase precession of intracellular theta oscillations, with the assumption that the cell receives an asymmetric ramp depolarization (<10 >mV) in the place field and rhythmic inhibitory and/or excitatory synaptic driving. Intracellular subthreshold membrane potential oscillations (MPOs) increase in amplitude and frequency, and show phase precession within the place field. Theta phase precession and MPO power …

Targeted Over-Expression Of Glutamate Transporter 1 (Glt-1) Reduces Ischemic Brain Injury In A Rat Model Of Stroke, Brandon K. Harvey, Mikko Airavaara, Jason Michael Hinzman, Emily M. Wires, Matthew J. Chiocco, Douglas B. Howard, Hui Shen, Greg A. Gerhardt, Barry J. Hoffer, Yun Wang

Neuroscience Faculty Publications

Following the onset of an ischemic brain injury, the excitatory neurotransmitter glutamate is released. The excitotoxic effects of glutamate are a major contributor to the pathogenesis of a stroke. The aim of this study was to examine if overexpression of a glutamate transporter (GLT-1) reduces ischemic brain injury in a rat model of stroke. We generated an adeno-associated viral (AAV) vector expressing the rat GLT-1 cDNA (AAV-GLT1). Functional expression of AAV-GLT1 was confirmed by increased glutamate clearance rate in non-stroke rat brain as measured by in vivo amperometry. AAV-GLT1 was injected into future cortical region of infarction 3 weeks prior …

Synaptic Reorganization Of Inhibitory Hilar Interneuron Circuitry After Traumatic Brain Injury In Mice, Robert F. Hunt, Stephen W. Scheff, Bret N. Smith

Physiology Faculty Publications

Functional plasticity of synaptic networks in the dentate gyrus has been implicated in the development of posttraumatic epilepsy and in cognitive dysfunction after traumatic brain injury, but little is known about potentially pathogenic changes in inhibitory circuits. We examined synaptic inhibition of dentate granule cells and excitability of surviving GABAergic hilar interneurons 8–13 weeks after cortical contusion brain injury in transgenic mice that express enhanced green fluorescent protein in a subpopulation of inhibitory neurons. Whole-cell voltage-clamp recordings in granule cells revealed a reduction in spontaneous and miniature IPSC frequency after head injury; no concurrent change in paired-pulse ratio was found …

Differential Levels Of Glutamate Dehydrogenase 1 (Glud1) In Balb/C And C57bl/6 Mice And The Effects Of Overexpression Of The Glud1 Gene On Glutamate Release In Striatum, Kevin N. Hascup, Xiaodong Bao, Erin R. Hascup, Dongwei Hui, Wenhao Xu, Francois Pomerleau, Peter Huettl, Mary L. Michaelis, Elias K. Michaelis, Greg A. Gerhardt

Neuroscience Faculty Publications

We have previously shown that overexpression of the Glud1 (glutamate dehydrogenase 1) gene in neurons of C57BL/6 mice results in increased depolarization-induced glutamate release that eventually leads to selective neuronal injury and cell loss by 12 months of age. However, it is known that isogenic lines of Tg (transgenic) mice produced through back-crossing with one strain may differ in their phenotypic characteristics from those produced using another inbred mouse strain. Therefore, we decided to introduce the Glud1 transgene into the Balb/c strain that has endogenously lower levels of GLUD1 (glutamate dehydrogenase 1) enzyme activity in the brain as compared with …

Increased Mitochondrial Calcium Sensitivity And Abnormal Expression Of Innate Immunity Genes Precede Dopaminergic Defects In Pink1-Deficient Mice, Ravi S. Akundi, Zhenyu Huang, Joshua Eason, Jignesh D. Pandya, Lianteng Zhi, Wayne A. Cass, Patrick G. Sullivan, Hansruedi Büeler

Neuroscience Faculty Publications

BACKGROUND: PTEN-induced kinase 1 (PINK1) is linked to recessive Parkinsonism (EOPD). Pink1 deletion results in impaired dopamine (DA) release and decreased mitochondrial respiration in the striatum of mice. To reveal additional mechanisms of Pink1-related dopaminergic dysfunction, we studied Ca²⁺ vulnerability of purified brain mitochondria, DA levels and metabolism and whether signaling pathways implicated in Parkinson's disease (PD) display altered activity in the nigrostriatal system of Pink1⁻/⁻ mice.

METHODS AND FINDINGS: Purified brain mitochondria of ^Pink1⁻/⁻ mice showed impaired Ca²⁺ storage capacity, resulting in increased Ca²⁺ induced mitochondrial permeability transition (mPT) that was rescued by cyclosporine A. …