Central Nervous System

Question 1

What are the four major neurotransmitters of the CNS that are amino acids?

Answer 1

Glutamate, glycine, GABA, asparte

Question 2

glutamate can make at least four other amino acids, what are these?

Answer 2

glutamine, glycine, GABA and asparte

Question 3

what are the four receptor sybtypes for glutamate?

Answer 3

NMDA, AMPA, Kainate and metabotropic

Question 4

compare ionotropic with metabotropic receptors

Answer 4

ionotropic receptors allow the passage of ions and are excitatory. metabotropic activate a second messenger system

Question 5

why is calcium important for long term potentiation (LTP)?

Answer 5

calcium, which enters the post synaptic neuron via NMDA receptors, increases the amount of AMPA receptors for depolarisation and triggers the release of nitric oxide and CamKII, which stimulates ‘long-lasting release’ release of glutamate and makes AMPA more sensitive to Glutamate, respectively.

Question 6

what are the two drugs currently used to block the effects of glutamate

Answer 6

Ketamine (anaesthesia, analgesia, depression) and Memantine (Alzheimer’s). Both are lipid soluble and can cross the blood brain barrier. PCP (illegal) and Ketamine block ion movement into the neuron

Question 7

What are the sites where drugs can manipulate effects of glutamate or GABA?

Answer 7

diagram. NMDA antagonist where glutamate binds, channel blocking drugs below Mg2+, and glycine/plyamine (modulatory sites) antagonists. GABA has benzodiazapine ‘inverse agonists’

Question 8

what is the life cycle of GABA?

Answer 8

presynaptically, glutamine -> glutamate -> GABA -> released into synapse -> reuptake to presynaptic neuron via GAT1 -> reuptake through glial cell via GAT2 and 3 -> GABA transaminase degrades GABA to glutamate

Question 9

what is the structure of a GABAa receptor?

Answer 9

five subunits (pentomer) and central conductive pore for chloride ions

Question 10

what do GABAb receptors do and what drug can modulate its effects?

Answer 10

increase outward K+ and reduce inward Ca2+ conductance and occur both pre and post synaptically
drugs: baclofen (decrease neurotransmitter release in excitatory spinal pathways and increase inhibitory activity

Question 11

Describe the pathway of glycine in the spinal cord and its structure

Answer 11

glutamate transaminase converts glutamate to glycine, glycine is exocytosed and binds to pentamer glycine recptors, which allow influx of Cl- (inhibitory), it is then ‘cleared’ via GlyT1 into astrocytes and GlyT2 into presynaptic neuron

Question 12

what is the difference between retrograde and anterograde amnesia

Answer 12

retrograde: cannot remember before the accident. anterograde: cannot remember after the accident.

Question 13

Neuroscience research involving the patient HM led to what discoveries?

Answer 13

The hippocampus/ medial temporal lobes are important for forming long-term memories and damage to these can result in anterograde amnesia. HM could not remember things for more than a few seconds after his injury (he had anterograde amnesia). Furthermore, his research supported that there are many types of LTM

Question 14

what are the types of declarative and procedural (non-declarative/show by doing) long term memory?

Answer 14

declarative: episodic (breakfast this morning) and semantic (name of the prime minister). Procedural: skill learning (riding a bike, tying shoe laces), priming (using recently heard/learnt words) and conditioning (salivating when you see a steak)

Question 15

how are long term memories made?

Answer 15

rapid and repeated firing down a pre-synaptic neuron makes the post synaptic neuron more responsive overtime

Question 16

What does protein Kinase 1 (CamKII) and protein Kinase 2 (via NO) do?

Answer 16

protein Kinase 1 (CamKII) makes AMPA receptor more sensitive to the binding of glutamate and protein Kinase 2 (via NO) releases more glutamate

Question 17

What is the importance of the CREB cycle in LTP?

Answer 17

activates the expression of other genes leading to the production of more ion channel receptors and synapses which cement the the connection between two repeatedly communicating neurons

Question 18

what is the histopathology of AD

Answer 18

intracellular neurofibrillary tangles (unravelling and phosphorylation of tau protein) and extracellular amyloid plaques (from APP amyloid precursor protein)

Question 19

what are the three cholinesterase inhibitors used to block the break down of ACh by AChE?

Answer 19

Rivastigimine, donepezil and galantamine

Question 20

What is Lewy Body Dementia and what are lewy bodies

Answer 20

LBD is either Parkinson’s disease or dementia with lewy bodies. lew bodies are abnormal deposits of the protein alpha-synuclein

Question 21

What are the symptoms for Parkinson’s disease

Answer 21

TRAP. tremor at rest, rigidity of limbs, Akinesia and postural problems