<p> Alzheimer&rsquo;s disease (AD) is the leading cause of dementia, accounting for 50 to 80 percent of dementia cases, and the prevalence of the disease is projected to increase significantly with time. AD is characterized by severe cognitive decline with age, ultimately requiring continued caregiving and eventually death. The pathology of AD is characterized by the presence of extracellular amyloid plaques, intracellular neurofibrillary tangles (NFT) composed of hyperphosphorylated tau protein, neuron loss, and evidence of inflammation indicated by the presence of reactive microglia and astrocytes. Frontotemporal Lobe Dementia (FTLD) is a rare form of dementia that is related to AD, most notably in the pathology of hyperphosphorylated tau and macroscopic brain shrinkage. It has been defined as one of a host of tauopathies, and has a more rapid onset than AD. Symptoms that resemble personality changes, moreso than memory loss, are characteristic of these other tauopathies (FTLD is a representative of a whole class of neurological disorders). Like AD, there are no known treatments or cures for FTLD. AD and FTLD are two manifestations of a class of diseases known as tauopathies, due to the presence of toxic forms of tau. </p><p> Tau is a protein normally found in neurons. It functions as a stabilizer for microtubules, and has a role in the trafficking of materials from the cell body to the presynaptic terminal. In AD and FTLD, tau can become hyperphosphorylated, which causes it to form twisted fibrils called NFTs. An emerging area of research is to identify antibodies that target tau as a way to clear tau pathology and hopefully reduce synaptic and neuron loss (Boutajangout et al., 2011b). While these diseases have no known cure or treatment at present, immunotherapy is emerging as a promising approach for treatment. The studies presented here investigated a variety of antibodies directed against tau, and incorporated different timeframes and administration routes to identify the best candidate for future clinical investigation of tau immunotherapy. </p><p> The mouse model rTg4510, known for expressing cognitive-related tauopathy, was primarily used to evaluate tau antibody effectiveness prior to clinical consideration. Our investigations began by utilizing a more familiar mouse which was also reported to express tau pathology. </p><p> Our studies first examined intracranial injection of a variety of antibodies using a mouse model previously reported to demonstrate tau pathology, to identify short-term clearance of tau pathology and NFTs. Next, we examined a more robust tau-producing mouse line, to further identify a most effective antibody, as well as to examine the time course of effect, after administration. A longer-term administration, and different route of administration was tested using mini-osmotic pump implantation into the mice, which provided for 28-day continuous infusion. This approach was followed with administration of antibodies, systemically. Behavioral analysis, in addition to pathological testing, was incorporated into the longer-term administration studies.</p>

<p> Previous studies have shown that FMRFamide alters the contractions of the smooth muscle tissues in <i>Lumbricus terrestris</i> including muscles along the body wall. Recently, numerous new annelid FMRFamide-related peptides (FaRPs) have been identified across the annelid in both polychates and clitellates, including tetrapeptides and N-terminally extended peptides. The primary objectives of this study are to analyze and compare the effects of FMRFamide (phenylalanine-methionine-arginine-phenylalanine-NH2), YMRFamide (tyrosine-methionine-arginine-phenylalanine-NH₂), FVRFamide (phenylalanine-valine-arginine-NH₂), YVRFamide (tyrosine-valine-arginine-phenylalanine-NH₂), AGAYVRFamide (alanine-glycine-alanine-tyrosine-valine-arginine-phenylalanine-NH₂), PAKHYVRFamide (proline-alanine-lysine-histidine-tyrosine-valine-arginine-phenylalanine-NH₂), and APKQYVRFamide (alanine-proline-lysine-glutamine-tyrosine-valine-arginine-phenylalanine-NH₂) on the longitudinal muscles of the body wall, specifically contraction rate and contraction strength. A body wall strip without the ventral nerve cord was placed in a tissue bath and exposed to increasing concentrations of these neuropeptides. Mechanical contractions were recorded on a computer with a Grass force transducer attatched to an Iworx A/D converter. </p><p> FMRFamide decreased contraction rate at a threshold of 10^-7 to 10^-6 M and increased the contraction amplitude at 10^-7 to 10^-6 M. YMRFamide had no effect on contraction rate, while being excitatory on contraction strength with a threshold of 10^-7 M. FVRFamide had no effect on contraction rate, while being excitatory on contraction strength at 10^-9 M. YVRFamide inhibited contraction rate with a threshold of 10^-9 M and increased contraction strength at 10^-9 M. APKQYVRFamide showed a biphasic response with regards to rate, decreasing it at 10^-9 M and increasing at 10^-8 M; it increased amplitude with a threshold at 10^-9 M. PAKHYVRFamide decreased rate at a threshold of 10^-9 M; it showed a biphasic trend in regards to contraction amplitude, increasing strength at 10^-9 M and decreasing it at 10^-6 M. AGAYVRFamide demonstrated a biphasic effect on contraction rate decreasing it at 10^-9 M and increasing it at 10^-8 M; it also showed a biphasic effect on amplitude, decreasing at 10^-9 M and increasing at 10^-7 M. The data demonstrate that both tetrapeptides and N-terminally extended peptides were biologically active in a concentration dependent manner with similar trends. This seems to suggest that there is some conservation in either neuropeptide presence or FaRP receptor across the annelid phylum. Comparing the four tetrapeptide sequences the data suggested that the second position was important for determining potency of the peptide where valine containing peptides had a lower threshold for increasing contraction rate than did the methionine containing peptides. The N-terminally extended YVRFamide data suggest that the type of extension is more crucial than the extension itself. On contraction rate AGAYVRFamide and APKQYVRFamide are both biphasic while PAKHYVRFamide is only inhibitory and is the only extended YVRFamide to have a positively charged amino acid in the X position (as in ABCX-YVRFamide), suggesting that the positive charge can negate the effect of the N-terminal extension.</p>

<p> Stroke is the fifth leading cause of death in the United States and a major cause of long-term disability in industrialized countries. The core region of an ischemic stroke dies within minutes due to activation of necrotic pathways. Outside of this core region is the penumbral zone, where some perfusion is maintained via collateral arteries. Delayed cell death occurs in this area due to the triggering of apoptotic mechanisms, which expands the ischemic injury over time. The cellular and molecular events that produce the expansion of the ischemic core continue to be poorly understood. The increases in the amyloid precursor protein and pathogenic secretases lead to the increase in amyloid-&beta; (A&beta;) production. The relatively small amount of research in this area has hampered development of stroke therapy designed to prevent neuronal and glial cell degeneration in the penumbra. Currently, there is a significant lack of therapeutic options for acute ischemic stroke, and no drug has been approved for treating patients at delayed time points (&ge; 4.5 hr post-stroke). </p><p> Afobazole, an anxiolytic currently used clinically in Russia, has been shown to reduce neuronal and glial cell injury <i>in vitro</i> following ischemia, both of which have been shown to play important roles following an ischemic stroke. Treatment with afobazole decreased microglial activation in response to ATP and A&beta;, as indicated by reduced membrane ruffling and cell migration. Prolonged exposure of microglia to ischemia or A&beta; conditions resulted in glial cell death that was associated with increased expression of the pro-apoptotic protein, Bax, the death protease, caspase-3 and a reduced expression in Bcl-2. Co-application of afobazole decreased the number of cells expressing both Bax and caspase-3, while increasing the cells expressing Bcl-2 resulting in a concomitant enhancement in cell survival. While afobazole inhibited activation of microglia cells by A&beta;_25-35, it preserved normal functional responses in these cells following exposure to the amyloid peptide. Intracellular calcium increases induced by ATP were depressed in microglia after 24 hr exposure to A&beta;_25-35. However, co-incubation with afobazole returned these responses to near control levels. Therefore, stimulation of &sigma;-1 and &sigma;-2 receptors by afobazole prevents A&beta;_25-35 activation of microglia and inhibits A&beta;_25-35-associated cytotoxicity.</p><p> Examining the molecular mechanisms involved in the increased neuronal survival demonstrates that ischemia or A&beta; results in an increased expression of the pro-apoptotic protein Bax and the death protease caspase-3, while at the same time decreasing expression of the anti-apoptotic protein, Bcl-2. However, unlike observations made with microglia, afobazole was unable to modulate this ischemia-induced expression, but was able to modulate A&beta;-induced expression of apoptotic proteins while still rescuing neurons from death. Additional experiments were carried out to understand this disparity between the failures of afobazole to prevent the up-regulation of pro-apoptotic genes while retaining the ability to mitigate neuronal death. Although the neurons were still alive they were in a senescent state and were unresponsive to depolarization by high K⁺. However, these findings are still positive due to the ability of afobazole to delay neuron death, thus minimalizing the toxic environment of the penumbra. </p><p> These comorbidities of ischemia and A&beta; toxicity may lead to potentiated responses and increase the risk for various vascular dementias. It was of particular interest to study how the convergence of ischemia, acidosis and A&beta; influence cellular activity and survival within core and penumbral regions. Application of A&beta; increased the [Ca²⁺]_i overload produced by concurrent ischemia + acidosis application in isolated cortical neurons. We found that the acid-sensing ion channels 1a (ASIC1a) are involved in the potentiation of [Ca²⁺]_i overload induced by A&beta;. Furthermore, afobazole (100 &micro;M) abolished A&beta; potentiation of ischemia + acidosis evoked [Ca²⁺]_i overload, which may represent a therapeutic strategy for mitigating injury produced by A&beta; and stroke.</p>

Most recreational users of 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy") also take cannabis, in part because cannabis can reduce the dysphoric symptoms of the ecstasy come-down, such as agitation and insomnia. Although previous animal studies have explored the acute effects of co-administering MDMA and Δ9-tetrahydrocannabinol (THC), the major psychoactive ingredient in cannabis, research on chronic exposure to this drug combination is lacking. The four experiments included in the current dissertation were designed to provide a wide breadth of information on the physiological, behavioral, and neurochemical effects of intermittent MDMA administration combined with daily THC exposure using a dosing regimen designed to reflect a clinically-relevant pattern of human ecstasy and cannabis co-usage. Because ecstasy and cannabis abuse usually starts during human adolescence, drug treatment was administered from postnatal day (PD) 35 to 60 in order to target the period of rat development lasting from approximately mid-adolescence to early adulthood. In addition, the dosing regimen in rats was also chosen to best correlate to patterns of human ecstasy and marijuana use. Drug-treated rats received two subcutaneous (s.c.) injections of 10 mg/kg of (±) MDMA-HCL every fifth day and/or a single daily intraperitoneal (i.p.) injection of 5 mg/kg of THC every day. The twice every fifth day MDMA dosing regimen was designed to simulate the intermittent weekend usage of ecstasy at "rave" parties and the "boosting" behavior (taking additional doses of MDMA in the same session to maintain desired effects) that has been noted in human users. THC was administered daily to simulate heavy cannabis usage in humans, which has been defined to mean using cannabis more than seven times per week. While THC helped to alleviate MDMA-induced anxiety-like, impulsivity-like, and exploratory behavior, co-administration of MDMA and THC additively produced depressive-like behavior and deficits in spatial memory. Furthermore, our experiments provide physiological and neurochemical evidence that helps to explain the behavioral outcomes, specifically as THC failed to protect against MDMA-induced neurotoxicity in the hippocampus, the brain region that is responsible for processing of spatial memory information, in both the SERT binding assay and in SERT autoradiography. Finally, our data suggested that male rats are more susceptible to MDMA-induced damages than females—which has significant implications for assessing the risks of recreational ecstasy and cannabis co-usage in humans.