L6 - The Plastic Synapse Flashcards Preview

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

Flashcards in L6 - The Plastic Synapse Deck (13):
1

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

2

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

3

What are the two major neurotransmitters in the CNS

1. Excitatory = Glutamate

2. inhibitory: GABA

4

What are the postsynaptic receptors for GABA?

GABA(a) receptors = Cl-

5

What are the postsynaptic receptors for Glutamate?

AMPA receptors = NA+ (the workhorse)

NMDA = Ca+ (the communicator)

6

What 3 synaptic properties define synaptic strength?

Number of synapses

Probability of release

Quantal size

7

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

specificity

co-operativity - cells that wire together fire together)

Longevity (can be measured for years in vivo

8

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

9

which receptor and neurotransmitter is responsible for LTP?

postsynaptic Ca2+ through NMDA receptor

How does the NDMA receptor act as a coincidence detector?

10

what goes wrong when trhe ability to remember is lost?

Synapses lose their ability to be plastic

- AD
- Down syndrome
- Age

11

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

12

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

13

What are the new ways to look at the brain?

MRI

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