Introduction Flashcards
An increase in intracellular concentrations of calcium lead to what 3 things?
Activation of calcium dependent enzymes
Initiation of gene transcription
Release of neurotransmitters from presynaptic sites
Are there different types of VGCa channels in the nervous system?
Yes. They differ in cellular distributions, physical and pharmacological properties & physiological roles
What types of calcium channels are there?
L, N, P, Q, R, or T types.
There are three different families of calcium channel a1 subunits
Cav1 genes encode L type
channels
Cav2 channels encode N, P/Q (alternative splicing), and R type
Cav3 genes encode T type channels
Cav1 channels consist of?
Cav1.1 , Cav1.2, Cav1.3, Cav1.4
Where are Cav1.1 and 1.4 expressed?
Skeletal muscle and retina
Where are cav1.2 and 1.3 expressed?
Primary cav1 channels expressed in the nervous system
High voltage activated channels
L, N, P/Q, R channels
Low voltage activated channels
T type channels
Which channels are expressed at presynaptic nerve terminals - to evoke neurotransmitter release
P/Q, N and to some extent R type
Which channels are expressed at cell bodies / dendrites - regulation of neuronal excitability
T type channels
Where are L type cav1.2 located?
Postsynaptically localised within dendrites in the hippocampus and cerebral cortex
Where are L type cav1.3 located?
Presynaptic and postsynaptic compartments
Where are L type cav1.4 located?
Presynaptically between the rod photoreceptors and bipolar neurons in the retina - mediate glutamate release - essential for responses to visual stimuli
