6-7. Electrophysiology and Neuronal signalling

Question 1

Example of cells which convey electrical signals

Answer 1

muscle cells
blood cells
endocrine cells
sensory cells
glial cells
immune cells
nerve cells

Question 2

What did Luigi Galvani do in the 1790s?

Answer 2

Frog leg nerve stimulation

Question 3

Advantages of cell-attached patch clamp recording (2)

Answer 3

Can record single channels

Do not change the channel properties

Question 4

Disadvantages of cell-attached patch clamp recording (3)

Answer 4

Poor pharmacology
Cannot change external medium in vicinity of the channel
Do not know the resting potential

Question 5

Advantages of cell-excised patch clamp recording (3)

Answer 5

Record single channels
Good pharmacology
Change inside/outside solutions

Question 6

Disadvantages of cell-excised patch clam recording (2)

Answer 6

May change the channel properties

Disrupted connection to cytoskeleton and intracellular effector proteins

Question 7

Advantages of whole-cell patch clamp recording (5)

Answer 7

Control of membrane potential and current
Multiple channel recording but properties of single channel can be evaluated
Good pharmacology
Change inside/outside solutions
Various modifications

Question 8

Disadvantages of whole-cell patch clamp recording (2)

Answer 8

Higher noise and leakage current

Some intracellular proteins can be washed out

Question 9

How many activation gates and inactivation gates in Na conductance determined by?

Answer 9

3 activation

1 inactivation

Question 10

The 3 voltage sensitive K+ Channels

Answer 10

K IR - inward rectifier
K V2.1 - delayed rectifier
K V4.1 - A type/transient

Question 11

3 K channels that require factors to open/close

Answer 11

BK - Ca++ dependent
SK - Ca++ dependent
K-ATP - ATP dependent

Question 12

5 Types of Na+ Channels

Answer 12

I
II
IIA
III 
VI

Question 13

Which type of Ca++ HVA channel is involved in muscle contraction?

Answer 13

L type

Question 14

Which toxin blocks N type Ca++ channels

Answer 14

Conus snail toxin

Question 15

Which toxin blocks P/Q type Ca++ channels

Answer 15

Funnel web spider toxin

Question 16

What forms the ion selectivity filter in ion channels?

Answer 16

S5 and S6

Question 17

What forms an inactivation gate in ion channels?

Answer 17

peptide chain between S6 of subunit III and segment S1 of subunit IV

Question 18

How is the inner ring of Na+ channel highly selective for monovalent Na+?

Answer 18

Contains D- E- K+ A - net charge of -1

Question 19

How is the inner ring of Ca++ channel highly selective for monovalent Ca++?

Answer 19

E-E-E-E- net charge of minus 4 so selective for divalent ions

Question 20

How does K+-channel pore filter the smaller Na+ ions out?

Answer 20

K+ ions can interact with O atoms on amino acids at the filter region to strip hydration shell.
Na+ ions are too small to interact with all 4 O atoms

Question 21

4 Characteristics of principal neurones

Answer 21

usually excitatory
usually have pyramidal shape and spines,
integrate numerous long-range inputs from other circuits
and local inputs from interneurons;
send their axons (innervate) other networks

Question 22

4 Characteristics of interneurones

Answer 22

usually inhibitory
do not have spines
get most inputs from local principal neurons,
send their outputs locally