Channels and Transporters (4) Flashcards
What is the effect of depolarization on a Na+ channel?
It increases the probability the channel will be open
How does a K+ channel differ from a Na+ channel? (4)
- opposite current direction -out
- longer latency for activation
- sustained response during depolarization
- many don’t inactivate but just close
What is the kv2.1 channel involved in?
Repolarization
-little inactivation
Describe a kv4.1 channel?
Inactivates rapidly to depolarization
Describe an inward rectifier channel?
More current flow during hyperpolarization than during depolarization (more current when potential is negative)
What does a fast after hyperpolarization do to the AP?
It shortens it by quickly repolarizing the membrane
BK K+ channels
activate by ca2+ and depolarization
they are rapidly inactivated
What does a medium after hyperpolarization do to the AP?
it controls the early interspike interval??
-slowly activates by ca2+ entry
-controls late spike frequency adaptation
IK and SK K+ channels are noninactivating
–I will ask about this because I don’t get it
Touch, hearing, osmoregulation are all perceived by what type of receptor?
Mechanosensitive - responds to deformation of membrane
Pain, temperature, inflammatory response are all sensed by what type of receptor?
Heat sensitive ion channels
What does TTX do?
Blocks Na+ channels
What does W-agatoxin do?
- from spiders
- blocks P/Q type ca2+ channels
What does saxitoxin do?
It is a homologue of TTX and blocks Na+ channels
What does W-conotoxin do?
It blocks N type ca2+ channels
Where is alpha toxin from and what does it do?
Scorpions
-prolongation of Na+ currents
Where is dendrotoxin from and what does it do?
Bees, wasps
-K+ channel blockers
