Ligand gated ion channels Flashcards
Where are ligand gated channels located in the nerve cell?
Sensory component of post synpatic cell (Soma, dendrites)
What is IPSP? EPSP?
Inhibitory post synaptic potential
Excitatory post synaptic potential
Name the EPSP neurotransmitters?
Acetylcholine
ATP
Serotonin
Glutamate
Name the IPSP neurotransmitters
GABA
Glycine
Name 3 ionotropic receptors
GABA/Gly/nAch
Glutamate
Purine
Are ion channels linked to ionotropic receptors hetereomeric?
Yes
Either 4 or 5 subunits to make 1 channel
Are ion channels selective for Cl-?
No
Where is the ligand binding site located on purine receptors?
Extracellular C termini loop
How many times does the nAch/GABA/Gly receptor pass through the membrane?
4
How many subunits form the ion channel linked to nAch/Gly/GABA?
5
What is the primary inhibitory neurotransmitter in central nervous system (brain)?
GABA
Which receptor binds alcohol, barbiturates and benzodiazepines?
GABA
What is the inhibitory neurotransmitter in the spinal cord other than GABA?
Glycine
What muscles does glycine target?
antagonist muscles
How many times does the glutamate receptor pass through the membrane?
3
How many subunits compose the ion channel that is linked to the glutamate receptor?
4 or 5
What ion channels is glutamate linked to?
Na+
K+
What receptor/ion channels are permeable to Ca+?
NMDA/AMPA
Why does NMDA require partial depolarization before opening Ca+ ion channels?
Remove Mg2+
What are NMDA channels inhibited by?
Ketamine and PCP
Is the nACh receptor excitatory or inhibitory?
Excitatory
Is the Glycine receptor inhibitory or excitatory?
Inhibitory
Is the GABA receptor inhibitory or excitatory?
Inhibitory
What are HT3R receptors?
Similar to nAch/GABA/Gly
Where do ligand gated receptors bind ligands?
Extracellular
Which subunit of the nAch/GABA/Gly receptor forms the aqueous pore/ion channel and is responsible for ion selectivity?
M2
What is the purpose for the intracellular portion of the subunit topology of nAch, HT3R, GABA, Gly?
processing, targeting, anchoring
Do Glutamate and purinergic receptors share the same topology as Gly/GABA/nAch?
No
How many alpha subunits are present in nAch?
2
Why is succinylcholine used during surgery?
Activates nAchR but then inactivates to prevent muscle contraction during surgery
Name an agonist for nAch
Trimethaphan
Which subunits determine subunit affinity and bind the ligand?
Alpha
What is the purpose for each alpha subunit to have a binding site?
Both must be bound for activation
Which subunit likely determines localization of nAchR?
Beta
What is the membrane potential for K+, Cl-, Cations, Na+?
-90
-68
-3
+60
If 2 ions are both considered dominant, what are their respective permeabilities?
1
What neurotransmitter is related to the HT3R receptor?
Serotonin
Why are antagonists (Dolasetron) of HT3R important?
Anti-diarrhea/nausea
