Glutamate ☺️ Flashcards
Describe the distribution and the properties of glutamate
AA
Mainly distributed in CNS
Very little in PNS
Most important excitatory NT in CNS
Describe the synthesis of glutamate
From extracellular => glia or neurone
-a oxoglutarate =(GABA transaminase)=> glutamate
In glia or neurones
Glutamate =(glutamine synthase)=> glutamine
-glutamine can be transferred between glia and neurones
Glutamine =(glutaminase)=> glutamate
From glia or neurone => extracellular
Glutamate =(transaminase)=> a oxoglutarate
Describe the storage of glutamate
vGluT 1,2,3 (Glutamate 2H exchanger)
-H movement driven by HATPase pump
Describe the release of glutamate
Ca dependent at axon end terminal
Describe the 2 receptors associated with glutamate
-what clinically useful drugs can be used here and what do they do
Ionotropic glutamate receptors (ligand gated ion)
- NMDA cation channels (influx of Na, Ca, efflux of K)
- AMPA cation channels (influx of Na, efflux of K
- Kainate cation channels (influx of Na, efflux of K)
Metabotropic glutamate receptors (GPCR)
NMDA - ketamine (channel blocker as analgesia), memantine (antagonist in dementia)
AMPA - perampanel (antagonist in epilepsy)
Describe the reuptake of glutamate
Excitatory AA transporter reuptakes glutamate into neurones/glia
-EAAT NaHGlu importer, K exporter
Describe the degradation of glutamate
Glutamate quickly removed from synaptic cleft by EAAT into neurones/glia
Converted to glutamine by glutamine synthase
Glutamine transferred to neurone
Converted back to glutamate by glutaminase
What 2 recreational drugs are implicated in glutamate pathways
Phencyclidine => hallucinogenic
Ketamine => hallucinogenic, dissociative
How are diseases implicated in glutamate pathways
-epilepsy
Epilepsy => increased glutamate or decreased GABA
Glutamate critical to all CNS function
