L6 - The Plastic Synapse Flashcards Preview

Seminars in Translational Medicine > L6 - The Plastic Synapse > Flashcards

Flashcards in L6 - The Plastic Synapse Deck (13):

What is the structure of the synapse?

pre-synaptic terminal
- machinery for making and concentrating transmitter in vesicles
- machinery for allow rapid fusion of vesicles

synaptic cleft
- essentially CSF

Postsynaptic membrane
- High concentration of membrane bound proteins that sense chemical transmission


Describe synaptic transmission

Action potential invades the pre-synaptic terminal

The rseulting depolarisation open Ca2+ channels

Ca2+ binds to a sensor protein

transmitter filled vesicles are drawn to the pre-synaptic membrane where they fuse

Transmitter spills across the narrow cleft

transmitter bind post-synaptic receptors that open allowing ions to flow


What are the two major neurotransmitters in the CNS

1. Excitatory = Glutamate

2. inhibitory: GABA


What are the postsynaptic receptors for GABA?

GABA(a) receptors = Cl-


What are the postsynaptic receptors for Glutamate?

AMPA receptors = NA+ (the workhorse)

NMDA = Ca+ (the communicator)


What 3 synaptic properties define synaptic strength?

Number of synapses

Probability of release

Quantal size


What properties do you need from synaptic plasticity if this is where memories are formed?


co-operativity - cells that wire together fire together)

Longevity (can be measured for years in vivo


What is LTP?

long term potentiation

Trains of stimulation resulted in a long-lasting increase in synaptic strength. these were specific, co-operative and long-lasting


which receptor and neurotransmitter is responsible for LTP?

postsynaptic Ca2+ through NMDA receptor

How does the NDMA receptor act as a coincidence detector?


what goes wrong when trhe ability to remember is lost?

Synapses lose their ability to be plastic

- AD
- Down syndrome
- Age


Why has there been show progress in understanding dementia and other neuro disorders?

Although synapses are critical to the formation of memory we are a long way from fully understanding how memories are formed

therefore it is difficult to fix


What are the problems with studying the brain?

encased in a hard shell

the electric signal (AP) occurs very quickly

the brain is a series of connected neuronal networks -- 100 billion neurons connected in trillions of possible ways


What are the new ways to look at the brain?


Dense Arrays of electrodes measuring electrical activity - can record many places but still only clusters of neurons