Reference no: EM132310384

Question 1

Prolonged exposure of nicotinic acetylcholine receptors to acetylcholine results in a change in the receptors that decreases their subsequent sensitivity to acetylcholine (i.e. higher acetylcholine concentrations are then needed to activate the receptor). This modification is known as desensitization. Some nerve terminals that release acetylcholine also contain the peptide neurotransmitter, calcitonin gene related peptide (CGRP). Following high frequency stimulation of these terminals, the post-synaptic nicotinic acetylcholine receptors become phosphorylated. Once phosphorylated, the receptors desensitize much more rapidly. The phosphorylation of the nicotinic acetylcholine receptor requires release of CGRP from the presynaptic terminals and a subsequent post-synaptic increase in cyclic AMP.

(a) Briefly discuss why a neurotransmitter peptide such as CGRP provides a suitable means to signal to the post-synaptic neuron that there has been high frequency stimulation of the nerve terminals.

(b) Outline a plausible series of molecular changes following the release of CGRP from the presynaptic terminal that could account for the increase in cyclic AMP and the phosphorylation of nicotinic receptors in the postsynaptic neuron. (Note: you do not need to know the precise details of the action of CGRP but should suggest how this could happen based on your knowledge of peptide neurotransmitters and the information provided above.)

(c) What changes would need to occur within the post-synaptic neuron to switch off all features of the response described in part (b) following subsequent degradation of the CGRP or its diffusion away from the post-synaptic neuron?

Question 2

Four research articles are listed below that investigated aspects of GABA-mediated neurotransmission in normal function or in disease.

You should choose one of these articles and obtain a copy. (You should be able to access copies electronically via the Library website or, in most instances, from the journal website.) Note: Some of these papers have supplementary files available online. In answering the questions (and particularly part c related to methods) you might need to access these supplementary files to find relevant information.

The questions below ask you to extract some key information from the paper you have selected and present it in your own words. You will probably not need to read the whole paper. Most (but not all) of the information you need will be in the Abstract and Introduction. You will not necessarily need to understand all of the details in the Methods and Results sections of the papers. You will be assessed on your ability to understand key information and describe it in your own words within the specified word limits. You will lose marks for not using your own words, for exceeding the word limits or for not citing any sources at the end of your answers.

Questions to answer

(a) What was the main issue(s) or question(s) addressed in the study? For this part of your answer, you should be describing the major specific aim (or in some instances two major aims) of the study, not the results or their broader implications. (in less than 75 words)

(b) Summarise the main results from the study. Your answer should focus on the key findings of the study and not their broader implications (in less than 100 words)

(c) Briefly describe one way in which a property directly related to GABA transmission, GABA receptors or GABAergic neurons was measured or experimentally manipulated in the studies described in this paper. This only needs to be a general description of the technique or manipulation that summarises the most essential aspects (i.e. what was measured or manipulated and a brief description of how this was done). You do not need to give a detailed description of the experimental procedure. (The description should be < 50 words. In some instances it could be considerably shorter).

Question 3

The NMDA receptor is one of the subtypes of ligand-gated ion channel for glutamate. Use a reference database such as PubMed or Web of Science to select a journal article meeting the following criteria:
a. was published in the Journal of Neuroscience (a well-regarded research journal in the neuroscience field) between 2016 and 2018;
b. is a report of original research (i.e. it includes methods and results) and is not just a review of other studies;
c. has the words "NMDA receptor" or "NMDA receptors" in the title;
d. provides information on the properties of NMDA receptors or the role of these receptors in normal nervous system function or nervous system disease.

(Note: It is likely given your current knowledge that you will not be able to fully understand many of the articles meeting the above criteria. However, you should be able to find articles for which you can understand the key points including the main conclusions relating to NMDA receptors.)

You should:

(a) provide citation details for the article using the format for listing references that is used in the Journal of Neuroscience

(b) Summarise in your own words and in less than 75 words the main new information from the study on the properties of NMDA receptors or their involvement in normal function or disease.