L11

Question 1

what channels are in dendrites

Answer 1

Shafts – Na and Ca channels, select K+ channels
Spines – N-type Ca channels

Question 2

what channels are in somas

Answer 2

Na+ and L/N/P/T-type Ca channels
Select K+ channels

Question 3

what channels are in axons

Answer 3

Hillocks – K-Ca channels
Shafts – Na channels
Nodes – Na and K+ channels
Terminals – N/P-type Ca channels

Question 4

ion channel structures

Answer 4

structure depends on genetic variability
genetic diversity underlies the diversity in ion channel structure

Question 5

K.v

Answer 5

4 alpha subunits
S4 is voltage sensor
S5-P-S6 has the pore –> selectivity filter

Question 6

voltage sensor in S4 (K.v)

Answer 6

positively charged arginine or lysine every 3/4 residues within S4
when channels open, charged amino acid moves through membrane electric field

Question 7

Na.v

Answer 7

most recent
essential role in initiation and propagation of APs in excitable cells
Important targets for local anaesthetics, anticonvulsants & antiarrhythmic agents

Question 8

Na.v 1.7

Answer 8

inherited erythromelagia
IEM mutations cause
- I-V hyperpolarisation (channel opens too easily)
- Slowed deactivation
- Hyperexcitability of neurones
Associated with intense episodic burning pain, redness and warmth.

Question 9

Na.v channeloptahies

Answer 9

Na1.1-1.2 = Epilepsy
Na1.5 = Cardiac arrhythmias
Na1.7 = IEM
Na1.7 = CIP