Neuroscience and Neurobiology Commons^™

Myosin Isoforms And Regulation Of Tonic And Phasic Contraction In Smooth Muscle, Qian Huang

Dissertations (1934 -)

The contractile properties of smooth muscle (SM) are broadly classified as tonic and phasic. Among the hypothesized underlying regulatory mechanisms for this difference is the different actomyosin ATPase kinetic properties of SM SMA/SMB myosin heavy chain (MHC) isoforms and the preferential expression of SMA and SMB MHC isoforms in tonic and phasic SM respectively. Thus, we hypothesized that SM SMA/B MHC expression determines tonic and phasic contractile patterns in SM.

To test the this hypothesis, the role of SMA and SMB MHC isoforms in tonic and phasic contractions was studied in phasic (longitudinal ileum and stomach circular antrum) and tonic …

Regulation Of System Xc- And Its Contribution To Cell Death, Xiaoqian Liu

Dissertations (1934 -)

The main focus of the studies in this thesis involves examining the role of cystine/glutamate exchange (system xC-) in neuronal death in primary cortical cell culture, with an emphasis on how glial function affects neuronal cell death. System xC- is a sodium-independent transporter that mediates cystine uptake and glutamate release. It accounts for most of the cystine uptake in astrocytes in mature cultures, providing the rate limiting substrate for synthesis of the main endogenous antioxidant glutathione. The glutamate released by system xC- may lead to excessive extracellular glutamate and cause excitotoxicity.

β-N-methylamino-L-alanine (BMAA) is a non-protein amino acid that may …

Corticosterone-Induced Potentiation Of Cocaine Seeking: A Potential Role For Organic Cation Transporter 3, Evan N. Graf

Dissertations (1934 -)

While it is known that stress plays a role in the relapse of cocaine-seeking behavior, recent studies demonstrate that stress may be acting as a "stage setter" rather than directly triggering further cocaine use. This model suggests stimuli that do not normally evoke relapse under stress-free conditions may result in drug seeking when the exposure occurs under stressful conditions. In this study, we examined the corticosterone-dependent potentiation of cocaine-induced reinstatement by a stressor, electric footshock (EFS), in rats following cocaine self-administration and extinction. We found that in rats with a history of drug exposure under low intake conditions, footshock alone …

Dysregulation Of System Xc- And Its Impact On Cocaine Seeking, Aric Madayag

Dissertations (1934 -)

Abnormal glutamate signaling in the brain, particularly in the nucleus accumbens core, contributes to compulsive cocaine-seeking behavior. In the nucleus accumbens, two distinct pools of glutamate exist. The synaptic pool stimulates excitatory postsynaptic receptors, leading to cocaine seeking. Cystine-glutamate exchange by system xc- contributes to the extrasynaptic pool and regulates neurotransmission by activating extrasynaptic receptors including inhibitory Group II metabotropic glutamate receptors, positioning this as an important mechanism for regulating nucleus accumbens activity. We and others have found decreased levels of cystine-glutamate exchange in animals withdrawn from chronic cocaine administration. In chapter 1, we describe studies directly implicating diminished system …