Modulation of ion channel activities that regulate transmitter secretion

Question 1

Describe an Action Potential

Answer 1

• When membrane potential is at rest both Na and K channels are closed

Question 2

Desribe synaptic transmission

Answer 2

• An AP invades a presynaptic terminal

Question 3

What are the diff types of ion channels

Answer 3

Voltage-gated ion channels

Question 4

Desribe presynaptic ion chanel arrengenment

Answer 4

There are a number of diff ion channels tht are found on the presynaptic ion channel that can affect and result in changed in NM release

Question 5

List the diff Voltage gated ion channels

Answer 5

Calcium channels

Question 6

Describe the general structural topology of voltage gated ion channels

Answer 6

• There is the alpha subunit on the Ca channel; it consists of 4 domains and 6 transmembrane domains, and there is a little pore loop found between transmembrane domains 5 and 6

Question 7

Describe presynaptic Calcium channels

Answer 7

• Ca enters through presynaptic voltage-gated Ca channels and initiates the release of neurotransmitters.

Question 8

How do the various Ca binding proteins modulate Ca channels?

Answer 8

• CBD and IM modulate the function of Ca channels

Question 9

Describe the alpha 1 subunit

Answer 9

• The a1 subunit incorporates the conduction pore, the voltage sensors and gating apparatus, and most of the known sites of channel regulation by second messengers drugs and toxins

Question 10

Describe the synprimt site

Answer 10

SNARE proteins syntaxin 1A and SNAP 25 interact with the Ca channels by binding to the intracellular loop between domains II and III of the a1-subunit.

Question 11

What happens when synprint peptides are present

Answer 11

• When synprint peptides are applied they prevent the SNARE proteins from binding to Ca channels

Question 12

Presynaptic Ca channels

Answer 12

• The beta gamma subunit of G protein-coupled receptors can bind to these Ca channels and they can have a negative effect on these channels

Question 13

Potassium channels are crucial regualtors of

Answer 13

1. Neuronal excitability

Question 14

Where can K channels be found

Answer 14

They can be found in a number of places like the neuronal dendrites, axons, soma, and presynaptic channels

Question 15

What are the three categories of K channels and how do they affect neurotransmitter release?

Answer 15

• Low voltage-activated K Channels

Question 16

What happens if we block any of the three K channels?

Answer 16

• If we block low voltage-gated K channels we start seeing aberrant AP firing leading to more neurotransmitter release

Question 17

Descirbe Sodium channels

Answer 17

• The primary role of sodium channels is to generate action potential

Question 18

What are the 5 post transcriptional modifications

Answer 18

1. RNA editing

Question 19

How do translational repressors affect the affect Na channels?

Answer 19

We have a translation repressor that can a bind to mRNA of Na channels repressing translation resulting in fewer fucntional Na channels expressed on the membrane

Question 20

List the diff short term synaptic plasticity

Answer 20

Facilitaiton

Question 21

Describe Facilitaiotn and depression when looking crayfish neuromuscular juncution

Answer 21

• There are two types of motor neurons phasic and tonic

Question 22

Descirbe facilitation, depression, and augmentaiton with PTP

Answer 22

• In facilitation the NM release goes up while stimulating; when we stop stimulation it goes back to the baseline

Question 23

What are some proposed mechanisms for facilition

Answer 23

• The residual Ca hypothesis

Question 24

The residual Ca hypothesis

Answer 24

• When two AP occur in a short time

Question 25

Residual Ca binds to a facilitator sensor

Answer 25

• AP and Ca enters the presynaptic temrial and binds to syanototagmin and triggers NM release

Question 26

Spike broadening: inactivation of K channels

Answer 26

• Synaptotagmin on the synaptic vesicle

Question 27

Calcium current facilitation

Answer 27

• Ca binding proteins can effect ca channel function

Question 28

Ca current facilitation and (IM) site

Answer 28

• If we have two AP we get an increase in Ca current in response to second AP

Question 29

Buffer saturation

Answer 29

• Ca buffer are Ca binding proteins