Neurotransmitter systems II:GABA and glycine Flashcards
What do inhibitory neurotransmitters do and how does this happen?
Inhibitory neurotransmitters hyperpolarize membranes:
- This happens by the ligand binding Cl- to enter the cell
- Also it can happen by opening K+ channels causing K+ to leave the cell
What is GABA synthesised by alongside what cofactor and enzymes?
Synthesised by glutamate converted to GABA by glutamate decarboxylase with cofactor vitamin B6
Where is GABA synthesised?
Synthesised in the nerve terminals
What is GABA transported into vesicles by?
Transported into vesicles by VIAAT
What shape are vesicles which contain glutamate?
Vesicles which contain glutamate are round
What shape are vesicles which contain GABA or glycine?
Vesicles which contain GABA or glycine are more oval shaped
What is the GABAA receptor?
Is a ligand gated cl- channel
What structure does a GABAA receptor have?
Has a pentameric structure
What subunits are possible in a GABAA receptor?
- 6 alpha subunits
- 3 beta subunits
- 3 gamma subunits
What is the most common configuration of a GABAA receptor?
-2 alpha,2 beta, 1 gamma is the most common configuration
Where are GABAA receptors most commonly found?
Most commonly found postsynaptically
What 3 things is GABA activity terminated upon?
- Terminated upon the reuptake of GABA by GAT
- By the breakdown of GABA by GABA transaminase
- By the diffusion of GABA away from the synapse
What binding sites does a GABAA receptor have?
Has multiple sites
-Agonist/Antagonist binding site
-2 GABA need to bind between alpha and beta interface
for channels to open
-Benzodiazepine binding site
-Channel modulators
-These tend to increase conductance of Cl- through
channels
-Allosteric modulators
-Channel blockersWhat is a GABAB receptors?
Is a G protein coupled receptor
What can GABAB receptors form?
Can form dimers
