VGCC
2022-05-05: reference:
VGCC (Voltage-gated calcium channel) #
-
Permeable to Na+, but at 1/1000 permeability of Ca2+. - [SNARE] proteins like synaptotagmin at presynaptic Synapses are located next to them. As such, Ca2+ influx is effective immediately and exocytosis takes about 300 μs and it does not require concentration to affect the whole cytoplasm or anything. Calcium channels can bind directly to vesicle proteins.
- They are normally closed, and open when depolarized(+ influx).
Types #
- High-voltage-gated:
- L-type (Cav1.1-4): Excitation-contraction/transcription coupling.
- P/Q (Cav2.1),
- N (Cav2.2),
- R (Cav2.3) type: neurotransmission.
- T- (Cav3.1-3) (low-voltage-gated) and L- type are pacemakers.