Epilepsy research group

Your epilepsy research group has received reports from physician colleagues in the Michigan Medicine Department of Neurology that a less-commonly prescribed antidepressant (GLH) may have anticonvulsant effects in patients with epilepsy. A search of the primary research literature available in NCBI PubMed provides you with some preliminary, although incomplete, information: - It is widely thought, though unconfirmed, that GLH’s activity is mediated through its effects on serotonergic neurotransmission. - Patients typically lost a moderate amount of weight while they were taking the drug. You plan to generate data about the mechanism of action of GLH and its efficacy as an anticonvulsant in the hopes of repurposing this drug for seizure control. Available tools: (you may describe others; you do not need to use all of these) Mice with genetic deletions of specific 5-HT2 receptor subtypes, or of other proteins such as SERT. Mice experiencing spontaneous seizures due to mutations (such as Scn1a+/- mice). Zebrafish which exhibit spontaneous epileptiform activity (Scn1Lab or scn1a fish) Unmodified (wild type) mice and rats. 5-HT2 Agonists: Ag-AC (2A/2C), Ag-A (2A), Ag-B (2B), Ag-C (2C), Ag-BC (2B/2C), PanAg (nonspecific = agonist to any 5-HT2 receptor). 5-HT2 Antagonists: Ant-AC (2A/2C), Ant-A (2A), Ant-B (2B), Ant-C (2C), Ant-AB (2A/2B), Ant-BC (2B/2C). SERT antagonist: Fluoxetine. Serotonin releasing agent: Fenfluramine. Drugs to induce in vivo seizures or in vitro epileptiform activity. Equipment or other necessary reagents to perform any experiment we have discussed in this module. For each experiment in each question below, your answer must include: Experimental design (5 points): Identify what type of experiment you have selected (microdialysis, fish field potentials, etc.), the model you will use (in vitro, animal model, etc.), and how your chosen experiment will answer the question/test the hypothesis. Variables (5 points): Describe all independent variables that you will be manipulating (conditions, drug treatment, concentrations, etc). Identify your positive and negative control(s). Data (5 points): Assume that your hypothesis is correct. Describe the results, in detail, that you would predict. You may describe this in text or include a simple example figure. Interpretation (5 points): Explain why/how the data you have described support the conclusion(s) you are drawing from the experiment. Question 1 (20 points) Based on its observed effects in patients with depression, you hypothesize that GLH acts as a serotonin reuptake inhibitor. Design one experiment to test this hypothesis. Question 2 (40 points) You next hypothesize that the effects of GLH are mediated by serotonergic signaling, specifically via agonism of the 5-HT2C receptor. Other studies have shown that agonism of either 5-HT2C or 5-HT2B receptors mimics the anorectic effects of fenfluramine, allowing you to use weight loss and feeding behaviours as a way to examine GLH’s mechanism of action. Design two different experiments to test your hypothesis about GLH and 5-HT2C. Each experiment should utilize at least 3 pharmacological agents in addition to GLH, including agonists and/or antagonists as appropriate (see page 1). Plan your experiments so that each one generates a different type of data as its output (e.g., not both measuring food intake). Question 3 (20 points) Now that you’ve gathered more data regarding the mechanism of action of GLH, you return to your central hypothesis for this study. Design one experiment to test the hypothesis that GLH can act as an anticonvulsant. Question 4 (20 points) You confirm that GLH does exhibit anticonvulsant effects. (Hooray!) A pilot experiment, unexpectedly, determines that this is not mediated by the 5-HT2C receptor, and after some exploring in PubMed you hypothesize that the anticonvulsant activities of GLH are mediated by agonism of 5-HT2A receptors. Design one experiment to test your new hypothesis. (Do not use the same experimental model as in in Question 3.)