MSN 671 Module 3 Focus Points
Ligand-gated ion channels - answer Activated by the binding of a neurotransmitter,
drug, or hormone.
Voltage-sensitive ion channels - answer Activated by changes in membrane voltage or
charge.
Ionotropic receptors - answer Another name for ligand-gated ion channels.
Clinical relevance of ligand-gated vs voltage-sensitive channels - answerLGICs → rapid
effects (e.g., benzodiazepines, ketamine); VSSCs/VSCCs → anticonvulsants, mood
stabilizers, analgesics.
Dual role of ligand-gated ion channels - answerThey act as both receptors and ion
channels.
Structure of LGICs - answerSeveral subunits arranged around an ion channel with
binding sites for NTs, drugs, ions, and allosteric modulators.
Pentameric receptors - answerReceptors with 5 subunits.
Tetrameric receptors - answerReceptors with 4 subunits + re-entrant loop.
Examples of pentameric receptors - answerGABAA_AA, Nicotinic acetylcholine receptor
(nAChR), 5-HT3, Glycine receptor.
Examples of tetrameric receptors - answerAMPA, NMDA, Kainate (glutamate
receptors).
Pentameric LGIC subtypes - answerGABAA_AA, nAChR, 5-HT3, Glycine receptors.
Tetrameric LGIC subtypes - answerAMPA, Kainate, NMDA.
Assembly of pentameric receptors - answer5 subunits form a functional ion channel;
subunit composition defines receptor subtype.
Assembly of tetrameric receptors - answer4 subunits form a functional ion channel with
re-entrant loops; subunit composition can determine drug binding.
Allosteric modulation - answerBinding of a ligand at a site different from the NT site to
alter receptor/channel activity.
Ligand-gated ion channels - answer Activated by the binding of a neurotransmitter,
drug, or hormone.
Voltage-sensitive ion channels - answer Activated by changes in membrane voltage or
charge.
Ionotropic receptors - answer Another name for ligand-gated ion channels.
Clinical relevance of ligand-gated vs voltage-sensitive channels - answerLGICs → rapid
effects (e.g., benzodiazepines, ketamine); VSSCs/VSCCs → anticonvulsants, mood
stabilizers, analgesics.
Dual role of ligand-gated ion channels - answerThey act as both receptors and ion
channels.
Structure of LGICs - answerSeveral subunits arranged around an ion channel with
binding sites for NTs, drugs, ions, and allosteric modulators.
Pentameric receptors - answerReceptors with 5 subunits.
Tetrameric receptors - answerReceptors with 4 subunits + re-entrant loop.
Examples of pentameric receptors - answerGABAA_AA, Nicotinic acetylcholine receptor
(nAChR), 5-HT3, Glycine receptor.
Examples of tetrameric receptors - answerAMPA, NMDA, Kainate (glutamate
receptors).
Pentameric LGIC subtypes - answerGABAA_AA, nAChR, 5-HT3, Glycine receptors.
Tetrameric LGIC subtypes - answerAMPA, Kainate, NMDA.
Assembly of pentameric receptors - answer5 subunits form a functional ion channel;
subunit composition defines receptor subtype.
Assembly of tetrameric receptors - answer4 subunits form a functional ion channel with
re-entrant loops; subunit composition can determine drug binding.
Allosteric modulation - answerBinding of a ligand at a site different from the NT site to
alter receptor/channel activity.
