8 - Techniques in neuropharmacology

Question 1

How do we measure bioelectricity

Answer 1

Patch only

Question 2

Small electrodes can record activity of

Answer 2

One neuron

Question 3

Larger electrodes record the activity of

Answer 3

Several neurones

Question 4

What is a microelectrode

Answer 4

h87lass electrode connects to amplifier

Question 5

What cells are used for electrophysiology studies

Answer 5

Oocytes mainly

Some neurons

Question 6

What are pros of using oocytes (2)

Answer 6

Express proteins well
Good for mutations
Technically easy

Question 7

What are some cons of using oocytes (3)

Answer 7

Frog oocytes
Difficult to exchange drugs
Difficult to get good electrical control of the cell in neurons as only one electrode, noisy, hole in cell

Question 8

What does patch clamp allows us to do

Answer 8

Control the voltage of most mammalian neurons or ‘clamp’ the voltage

Question 9

What does the amplified of the patch clamp do

Answer 9

Maintains a membrane potential and measures the currents require dot maintain it

Question 10

What is an upward current

Answer 10

Positive ions leaving

Negative ions entering

Question 11

What does a current clamp measure

Answer 11

Change in membrane potential caused by the applied current

Question 12

What does a voltage clamp measure

Answer 12

The transmembrane current required to maintain the voltage

Question 13

What is the pro of current clamping

Answer 13

Mimics current produced by a synaptic output

Question 14

What is the pro of voltage clamping

Answer 14

Control voltage to limit the changing variables

Question 15

What does patch clamping allow us to do

Answer 15

Low noise

can measure the current flow through 1 channel

Question 16

What does whole-cell patch clamping allow us to do

Answer 16

Study ion channels of:

• isolated cells
• cell culture
• cells in brain slices or in vivo

Question 17

What affects the size of the post-synaptic current

Answer 17

1) How much glutamate is released
2) How many post-synaptic AMPA receptors
3) Location of AMPA receptors
4) Phosphorylation state of AMPA receptors
5) Voltage of post-synaptic cell
6) Ions inside and outside the cell

Question 18

What are some cons of patch clamping

Answer 18

1) Quite hard
2) Can be expensive
3) Not suitable fo rall cells
4) One cell at a time
5) You lose things when you prepare the cells

Question 19

What is optogenetics used for

Answer 19

Selective activation of sub-population neurons

Fantastic temporal control

Question 20

What is immunohistochemistry

Answer 20

Identification of specific tissue components by means of a specific antigen reaction tagged with a visible label

Question 21

What does immunohistochemistry allow

Answer 21

Localisation of the antigen within a cell or tissue

Question 22

What is an example of an enzyme linked secondary

Answer 22

Biotin bound to high affinity Avidin

Question 23

Why do secondaries have high sensitivity

Answer 23

Reaction is amplified

Question 24

What are some pros of fluorescent secondaries

Answer 24

1) High structural resolution possible
2) Quantification
3) Versatile
4) Multiple labelling
5) Live cells

Question 25

What are some negatives of immunohistochemistry

Answer 25

1) Can be false positives/negatives
2) Level of response depends on conditions and is variable between experiments
3) Appropriate controls need to be used
4) Tissue needs to be out of the animal/human
5) Often sliced into very small sections

Question 26

How do electrophysiology and immunohistochemistry complement each other

Answer 26

Electrophysiology - tells us about function

Immunohistochemistry - tells us about location and sometimes state