Flashcards in Electrical Excitability Deck (15):
How many transmembrane domains are in a GPCR?
What type of calcium channel do conotoxins block?
N, P and Q-type
State where L-type calcium channels can be found
Muscle, neurons and lungs
State where N type calcium channels can be found
State where P/Q type calcium channels can be found
State where R type calcium channels can be found
State where T-type calcium channels can be found
Describe the alpha subunit of a calcium channel
The pore-forming subunit
What is the function of subunits other than the alpha in calcium channels?
Fine tune properties and regulate channel activity.
Has a location for phosphorylation so kinases can alter their action.
How does phosphorylation of L-type calcium channels alter their activity?
Describe the stages in neurotransmitter release.
Calcium entry through channels
Vesicle brought close to the membrane
Binds snare complex to make a fusion pore
Transmitter released through this pore
How many acetylcholine need to bind to the acetylcholine receptor to induce a conformational change?
Describe a reversal potential.
When a channel is permeable to two ions which have different equilibrium potentials, it's activation will causes the membrane potential to move towards the Eion which is furthest away. At the point equidistant between them is the reversal potential. There is no net flow of charge.
If the external calcium concentration is lowered, what effect will this have on the end plate potential?
They will decrease in amplitude because neurotransmitter release is dependent on calcium entry. Not enough acetylcholine will be released and bound to trigger the potential.