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Investigation To Examine The Profile Of Auditory Brainstem And Hearing Thresholds Using Tone Burst Audiometry Brainstem Response In A Preclinical Migraine Model, Megan Huelsing
MSU Graduate Theses
Migraine is a disabling neurological disease that is characterized by prominent auditory symptoms, including hyperacusis, which is defined as extreme sensitivity to sounds. The goal of this study was to investigate changes in hearing sensitivity and neural changes in the brainstem by measuring neural activity of the auditory brainstem in an established preclinical model of chronic migraine. To induce a chronic migraine state within the trigeminal system, male and female Sprague Dawley rats were subjected to three known human risk factors including neck muscle tension and REM sleep deprivation that promote latent sensitization, and exposure to a pungent odor, which …
Systemic Insulin Sensitivity And Skeletal Muscle Akt Signaling In Rats Artificially Selected For Low And High Aerobic Capacity, Kyle Levi Fulghum
Systemic Insulin Sensitivity And Skeletal Muscle Akt Signaling In Rats Artificially Selected For Low And High Aerobic Capacity, Kyle Levi Fulghum
MSU Graduate Theses
The mechanism(s) linking physical inactivity, obesity, and type-II diabetes are unclear. I hypothesized low intrinsic aerobic capacity is associated with reduced systemic insulin sensitivity via skeletal muscle insulin signaling. After 34 generations of selective breeding, high aerobic capacity (HCR) rats exhibited an 8-fold increase in running distance vs low aerobic capacity (LCR) rats (n=14 per group). LCR rats had higher rates of weight gain vs HCR (p<0.05) though food consumption was constant (p=0.86) over a 12-week study. Rats were divided into 4 groups: 1) LCR-Sham Surgery, 2) LCR-Catheterization, 3) HCR-Sham Surgery or 4) HCR-Catheterization (n=7 per group). Euglycemic-hyperinsulinemic clamps on catheterized rats tested insulin sensitivity while sham LCR and HCR were used for basal tissue analysis. Plasma insulin levels did not differ during the clamps, but LCR required lower glucose infusion rates than HCR (p<0.05). Upon insulin stimulation, both absolute and normalized phospho-Akt(Ser473) of soleus muscle were significantly increased in HCR above basal group (p<0.05), but not in LCR. No difference was observed between insulin-stimulated phospho-Akt(Ser473) of HCR and LCR groups . These data support that LCR is linked to a reduction in insulin sensitivity in vivo without impairments of insulin-stimulated skeletal muscle phospho-Akt(Ser473) vs HCR rats.