Calcium Channel Gating

Question 1

What are the roles of L-type channels in the CVS

Answer 1

Maintains the platue phase of the action potential, generates the depolarising phase of action potentials in SA node and AV node, generates major component of Ca2+ influx in CICR in Ventricular cells, provides an important influx plathwya for ca2+ in the control of VSM tone.

Question 2

What does Cs+ do to K+ channels

Answer 2

Blocks them.

Question 3

What do pre-pulses do?

Answer 3

The inactivate voltage gated ion channels.

Question 4

What is the effect of forskolin on the l-type ca2+ current?

Answer 4

Activates AC, AC increases cAMP, cAMP leads to activation of PKA which phosphorylates the channel and leads to a larger current leading to opening of the channel at higher potentials, moving the negative shift in avalabitlty and activation curves.

Question 5

What is the Ca2+ window current?

Answer 5

Cross over of avalibity and activation curve leads to a window current more info needed.