Lecture 4: Synaptic Transmission

Question 1

When ions/small molecules exchange between cells

Answer 1

Electrical synapse

Question 2

What is mediated by neurotransmitters

Answer 2

Chemical synapse

Question 3

Majority of neuronal communication occurs via ______

Answer 3

Chemical synapse

Question 4

Gaseous and lipid transmitters are less common, can easily cross ______ therefore not stores in synaptic vesicles

Answer 4

Lipid bilayer

Question 5

Most if not all neurons can release multiple ____

Answer 5

Neurotranmitters

Question 6

In neurodegenerative diseases, not only the main
neurotransmitter but also_____ are lost.

Answer 6

Co-transmitters

Question 7

Axon terminal express ___ , ___, ____

Answer 7

Na+
K+
Ca++

Question 8

Neurotransmission:
Transmitter release:
1. _____ arrives
2. ___ influx
3. ____

Answer 8

Action potential
Ca2+
Exocytosis

Question 9

____ Receptor
Time course -fast
Cellular response - excitatory or inhibitory
Mediator of cellular response - receptors = ion channels

Answer 9

Ionotropic

Question 10

_____ receptor
Time course : long lasting
Cellular response: excitatory or inhibitory (depends
on signaling pathway involved)
Mediator of cellular response: second messenger regulates downstream effectors

Answer 10

G protein-coupled (GPCR)

Question 11

IONOTROPIC RECEPTOR
Time course :____
Cellular response: ______
Mediator of cellular response: ___=___

Answer 11

Fast
Excitatory or inhibitory
Receptors = ion channels

Question 12

___ ‘s are very diverse
- one of the most common drug targets

Answer 12

GPCR

Question 13

Some neurotransmitters activate both ___ and ___

Answer 13

Ionotropioc receptor and GPCR

Question 14

Neuroleptics receptors are ____

Answer 14

GPCR

Question 15

Depending on the receptor the same transmitter can induce different ____ response

Answer 15

Postsynaptic

Question 16

Different receptors can:
1. Have different ___
2. Be linked to different ___ mechanisms
3. Be expressed at different ___ mechanisms
4. Can be regulated___

Answer 16

Kinetics
Signalling
Sub cellular
Differentially

Question 17

What triggers neurotransmitter release?

Answer 17

Calcium

Question 18

How is neurotransmission terminated (3 answers)?

Answer 18

Uptake, degradation, diffusion

Question 19

Which processes of neurotransmission are specific to a
neurotransmitter?

Answer 19

Synthesis, receptors, reuptake, degradation

Question 20

Which steps of neurotransmission are common to chemical synapses?

Answer 20

Action potential, Ca++ influx to axon terminal, exocytosis

Question 21

What are the two major classes of receptors involved in neurotransmission? Main differences?

Answer 21

• Ionotropic receptors: fast, mediated by ionic current
• metabotropic (G protein-coupled) receptors: slow & long lasting, mediated
by second messengers

Question 22

What is the physiological significance of receptor diversity for a given
transmitter?

Answer 22

Different receptors can mediate distinct responses (excitatory or inhibitory,
time course, subcellular localization) • Different receptors can be regulated differently

Question 23

Change in postsynaptic membrane potential as a result of ____

Answer 23

Neurotransmission

Question 24

EPSP and IPSP are due to
• activation of ______ or
• activation/ inhibition of _____ via GPCRs

Answer 24

Ionotropic receptors
Ion channels

Question 25

Postsynaptic potential • Initially starts locally at the synapse and propagates along the _____ • Postsynaptic potentials are ____ potentials (amplitude can vary) • The ____ diminishes with distance traveled (not regenerative)

Answer 25

Cell membrane Graded Amplitude

Question 26

Individual postsynaptic potential may be too small to_____ an action potential, but multiple postsynaptic can add up to become larger

Answer 26

Initiate

Question 27

_________ of postsynaptic potential can occur when multiple synapses activate simultaneously

Answer 27

Special summation

Question 28

A single synapse activating multiple times in quick succession can result in temporal summation of postsynaptic potential

Answer 28

Temporal summation

Question 29

Synaptic integration 1. Three excitatory neurons fire, their grades potentials separately are all below ____ 2. ______ arrive at trigger zone together and sum to create asuprathreshold signal 3. An ___ is generates

Answer 29

Threshold Graded potentials Action potential

Question 30

• Spatial summation can occur between _____ and ____ synapses • Inhibitory signal dampens _____ signal

Answer 30

Excitatory and inhibitory Excitatory

Question 31

_______= magnitude of postsynaptic potential • Synaptic strength is not _____. It can be modulated

Answer 31

Synaptic strength Constant

Question 32

Any step of neurotransmission can be a target of synaptic modulation • ________ substance • ______ target

Answer 32

Psychoactive Drug

Question 33

Earlier synaptic activity altering later synaptic ______

Answer 33

Responses

Question 34

Synaptic ____: neuromodulator-dependent

Answer 34

Modulation

Question 35

Synaptic ____: synaptic activity-dependent

Answer 35

Plasticity

Question 36

Virtually every synapse in the nervous system can undergo synaptic _____ and _____

Answer 36

modulation Plasticity

Question 37

At synapses = synaptic _____ or synaptic ___ At cell body = ____ (synaptic integration)

Answer 37

Modulation Plasticity Summation

Question 38

1. _______________ • Physical innervation (hard-wired) • Rapid transmission of signals • Action potential • Synaptic transmission

Answer 38

Rapid and specific propagation of signal

Question 39

2. _________< _____ • Summation • Synaptic modulation • Synaptic plasticity • Convergence, divergence

Answer 39

Integration commutation

Question 40

3. _______ • Synaptic plasticity

Answer 40

Availability

Question 41

What are the differences between action potential and synaptic potential?

Answer 41

• Action potentials are all or none, regenerate while propagating along the axon • Synaptic potentials are graded, decays with time and distance traveled

Question 42

How can small postsynaptic potentials induce action potentials?

Answer 42

Summation

Question 43

What are the similarity and difference between synaptic modulation and synaptic plasticity?

Answer 43

• Similarity: synaptic strength changes • Difference: synaptic modulation is typically induced by neuromodulators (endogenous modulators, drugs etc); synaptic plasticity is induced by synaptic activity (previous synaptic activity altering future synaptic strength)