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Inhibitory transmission - Coggle Diagram
Inhibitory transmission
GABA receptor
GABAaR
- major inhibitory receptor
GABAaR enhancer: +ve allosteric modulator
- anxiolytic: reduces anxiety
- anticonvulsant: inhibits involuntary contraction
- analgesic: relieves pain
- amnestic: causes memory loss
- sedative
-
GABAaR inhibitors:
- proconvulsant
- anxiogenic: induces anxiety
-
transmision
- a-ketoglutarate triggers release of GABA-T (inhibitor)
- acts on GAD
- inhibits catalysis of glutamate to GABA
- VGAT transport GABA and glycine to vesicles for release
inhibition
feedforward
- bi-synaptic response
- GABA takes 1-5msec which limits excitatory summation
- active glutamate-gated ion channel produces excitation
- active GABA-gated ion channel produces inhibition
feedback
- pyramidial neuron (multipolar) activates GABA interneuron which inhibits the pyramidial neuron
GABAb
heterodimer
- GABAb1 binding domain
- GABAb2 G-protein coupling to Gi, Go
-
pre-synaptic activation
- Go-beta/gamma complex inhibits Ca channels
post-synaptic activation
- Gi-beta/gamma complex opens Ca channels
auto-inhibition
post-synapse
- GABA activates GABAaR Cl channels to inhibit
pre-synapse
- GABA activates GABAaR to inhibit Ca channels
-
Drugs
benzodiazepines
enhances GABA opening
only a1-3, 5 because of H residue
-
-
strychnine-sensitive glycine receptor related GABAaR
involved in
- respiratory rhythm
- motor control
- muscle tone
- sensory incl pain processing
transmission
- VIAAT transports glycine into vesicles
- glycine activates glycine receptor to conduct Cl
- glycine can then be removed by GLYT1 (into astrocytes) and GLYT2 (back in the neuron)
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