Topic 74 - Membrane receptor signaling Flashcards
1
Q
Words to include
A
- Transduction
- G-protein independent
- Transmembraen protein
- Ligand binding part
- Central part
- Inner part
- Phosphorylase activity
- Ligand bond
- IC peptide chain phosphorylase
- Nicotinic acetylcholine receptor
- Ion channel-forming transmembrane protein
- CNS
- PNS
- Conformational change
- Cation channel
- Local excitatory potential
- Action potential
- Glutamate-sensitive receptors
- Post-synaptic membrane-integrated cation channel
- Glutamate antagonists
- NMDA receptor (N-metil-D-asparate)
- Mg2+ dissociation receptor
- AMPA receptor
- Kainate-receptor
- NMDA receptor (N-metil-D-asparate)
- Anion receptor
- Anion channels
- Inhibitory synapses
- CNS
- Mediators
- GABA (Gamma Amino Butyric Acid)
- GABA-A receptor
- Ionotropic
- GABA-B receptor
- Metabotropic
- GABA-A receptor
- Glycine
- IC cAMP
- K+ channels
- GABA (Gamma Amino Butyric Acid)
2
Q
General
A
- Transduction = G-protein independent
- Receptor may be a special transmembrane protein of 3 parts:
- Ligand binding part (on EC side)
- Central part (passes through membrane)
- Inner part (on IC side – protein continues and exhibits phosphorylase activity)
- Ligand bond on outer surface IC peptide chain phosphorylates/activates receptor or cellular proteins biological action
3
Q
Name the membrane receptors
A
- Nicotinic acetylcholine receptor (n-Ach-R)
- Glutamate-sensitive receptors
- Anion receptors
4
Q
Nicotinic actylcholine receptor (N-Ach-R)
A
- Ion-channel-forming transmembrane protein
- Found in CNS and PNS
- In closed state before binding of ACh
- Binding of ACh → conformational changes → opening of cation channel (open state)
- Influx of cations (e.g. Na+) local excitatory potential and stimulation of action potential
- Channel returns to closed state after dissociation of ligand
- Family with 5 membrane-integrated (transmembrane) domains
- Subunits in skeletal muscle:
- 2 α subunits (Ach binding site)
- 2 β subunits
- 1 Δ subunit
- Subunits in nervous tissue: (insensitive to curare)
- 2 α subunits (Ach binding site)
- 3 β subunits
- Subunits in skeletal muscle:
- The whole receptor serves as an ion channel
- Ligand binding site (EC side)
- The receptor can be inhibited by d-tubocurarine (curare)
5
Q
Glutamate-sensitive receptors
A
- Post-synaptic membrane-integrated cation channel
- 3 main groups according to glutamate antagonists:
-
NMDA receptor (N-metil-D-aspartate)
- Binding of Mg2+ keeps the receptor closed
- Mg2+ dissociatied after receptor activation
- AMPA receptor
- Kainate-receptor
-
NMDA receptor (N-metil-D-aspartate)
- Glutamate also binds to various metabotropic receptors
6
Q
Anion receptors
A
- Opening of anion channels important in inhibitory synapses of CNS
- 2 main mediators:
-
GABA (Gamma Amino Butyric Acid)
- Acts on GABA-A (ionotropic) or GABA-B (metabotropic)
- GABA-B decreases IC cAMP and effects K+ channels
- Glycine
-
GABA (Gamma Amino Butyric Acid)