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3 Cards in this Set
- Front
- Back
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What is a ligand gated ion channel?
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Porous channel in cell membrane typically composed of 4 (tetramer) or 5 (pentamer) protein subunits. Each subunit has 4 transmembrane domains. Ligand binding can open or close the channel allowing flux of certain ion size/charge/etc.
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What is a G-protein Coupled Receptor (GPCR)?
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Protein receptor in cell membrane with 7 transmembrane domains (amino extracellular, carboxy intracellular). Ligand binds extracellular face of R, G-protein is coupled to intracellular face of R. The g-protein (alpha, beta, gamma subunits) couples the receptor to an effector, which can be adenyl cyclase, an ion channel, or a phospholipase. The alpha subunit hydrolyzes GTP which activates the effector.
Examples include muscarinic ACh Rs, GABA(b), some glutamate Rs, all other receptors for amine and peptide NTs. |
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What are the mechanisms by which a drug can affect neurotransmission?
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(1) Act as an agonist or antagonist at the NT receptor
(2) bind to a site distinct from the NT site and alter the receptors affinity for the native NT ligand (3) inhibit NT reuptake into the presynaptic nerve terminal (4) inhibit synthesis or metabolism of the NT (5) inhibit or potentiate NT release |
