2) Ghrelin receptors are expressed at many sites in the brain, but both their role at particular sites and whether/how ghrelin might reach those sites is uncertain.
Proposed question is:2) Ghrelin receptors are expressed at many sites in the brain, but both their role at particular sites and whether/how ghrelin might reach those sites is uncertain.Construct a feasible, testable hypothesis to explain the presence of ghrelin receptors in a particular brain area. Design and describe three complementary experimental approaches that address this hypothesis. Your answer should include comments on the limitations of the approaches selected.You will need to justify your choice of site and construct a plausible hypothesis about the potential role. You will need to design a set of three experiments, with a clear hypothesis in every case, consider the possible outcomes and explain how each possible outcome would be interpreted.In this assessment we are asking you to describe one ‘cycle’ of the scientific method from observation to hypothesis to experiment. In the context of this assessment, the cycle stops there – we are not asking you to describe the observations of your imagined experiments. However, the experiments you write about must be designed in a way that addresses your hypothesis, and the hypothesis must be related to the original observation.An example of the style of question that will be used in this assessment is given below. Before you start the course, you may not be familiar with some of the details given in this example, but these will become more familiar to you as the course progresses.You stereotaxically inject a virus into the hypothalamic ventromedial nucleus (VMH) of transgenic rats. The rats express Cre-recombinase in neurones endogenously expressing the oxytocin receptor. Injection of the virus is expected to result in the expression of Green Fluorescent Protein (GFP) in oxytocin receptor-bearing cells. You prepare acute brain slices from an ad lib-fed virally-infected rat and perform in vitro electrophysiology. You find that a bath application of a low concentration of oxytocin increases the firing rate of GFP+ cells but has no effect on GFP- cells. The increase in firing rate in GFP+ cells can be prevented by co-application with an oxytocin receptor antagonist. You repeat this experiment using acute brain slices from a virally-injected rat that has been fasted for 24hours. You find that bath application of the same concentration of oxytocin has no effect on the electrical activity of GFP+ cells. In your answer, briefly discuss why these findings might be important. Next, construct a testable hypothesis and set out the experiments you would perform to test it. These studies must involve three complimentary experimental approaches. You must explain what control experiments are necessary, and you must discuss the main limitations of your chosen experimental approaches. For each proposedexperiment you must state clearly how the experiment addresses your hypothesis. The experiments you suggest can be novel and ambitious, but should be feasible.