BIPN 140
LECT #9
1
DKBerg
NEUROTRANSMITTERS/RECEPTORS
I. NT Receptors
A. Ionotropic Receptors:
transmembrane proteins having an
internal pore (“ligand-gated ion channel”)
1.
Four TM domains
a)
nACh Receptors
**FIGURE 6.3a/c**.
b)
GABA
A
& glycine Receptors
2. Three TM helices
a)
AMPA receptors (glutamate Rs)
b)
NMDA receptors (glutamate Rs)
[subunit composition determines specific subtype properties, e.g.
calcium-permeable vs calcium-impermeable NMDA receptors]
**FIGURE 6.4a/b**.
B. Metabotropic receptors
1.
Seven TM regions
2. Shared NTs (with ionotropic Rs) but different outcomes:
linked to
intracellular pathways
3. G protein-coupled
**FIGURE 6.5**.
II. Classical Neurotransmitters
A.
Acetylcholine (ACh)
1. NT at the vertebrate NMJ
2. Rapid local synthesis:
choline acetyltransferase (ChAT); defines a
“cholinergic” neuron
3. Excess:
desensitization of receptor
**FIGURE 6.2**.
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