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60 Cards in this Set
- Front
- Back
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How do most CNS drugs act?
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alter synaptic transmission
AND modulate effects of neurotransmitters |
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How do a few CNS drugs act?
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voltage-gated ion channels
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Dale's hypothesis?
Is it true? |
Neurons use only one transmitter.
True for classical transmitters only. Neuropeptides are co-transmitters in many cells. |
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3 criteria for "transmitter"
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1. Presence- in presynaptic nerve terminals with its substrate and synthesizing enzyme
2. Release- release in response to depolarizing stimuli is CALCIUM dependent 3. Pharmacologic identity- effects of transmitter when applied experimentally must = effects of stimulating presynaptic pathway |
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Give 3 examples of small transmitters
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ACh
Amines- DA, NE, Epi, Serotonin Amino acids- glutamate, GABA, Glycine |
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Give 2 examples of peptide transmitters
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opiods
NPY |
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Give 2 examples of transmitter gases
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N2O
CO |
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How does an ionotropic receptor work
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transmitter binds multimeric ligand-gated ion channel -->
increased permeability to one or more ions --> either EPSP or IPSP |
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AMPA glutamate receptor
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excitatory inotropic
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kainate glutamate receptor
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excitatory ionotropic
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NMDA glutamate receptor
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excitatory ionotropic
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GABA receptor
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inhibitory ionotropic
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How do metabotropic receptors work
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transmitter binds receptor bound to G-proteins -->
activates second messengers (IP3, DAG) --> modulate cellular physiology |
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Metabotropic glutamate receptor
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metabotropic receptor
(if it were only that easy) |
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GABA-beta receptor
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metabotropic receptor
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alpha and beta adrenergic receptors
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metabotropic receptors
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Most excitatory synapses use...
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glutamate
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Glutamate transporters that take up glutamate are dependent on which ion?
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Na
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Where is glutamine made?
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Nerve terminal mitochondria
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Name three ligand gated ion channels/ionotropic receptors.
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AMPA
kainate NMDA |
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Other names for metabotropic glutamate receptors?
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mGluR1-8 receptors
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Which mGluR type(s) couples with G proteins and activates the IP3 system via PLC?
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Type I
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Which mGluR type(s) inhibit AMP synthesis by adenylyl cyclase?
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Types II and III
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Other than ligand binding, what else does the NMDA receptor need?
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membrane depolarization
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How does the NMDA receptor work?
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increases intracellular Ca --> act as second messenger
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Name five correlations to the NMDA receptor
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1. learning and memory
2. ischemic neuronal damage 3. epileptic seizures 4. PCP psychosis 5. ketamine anesthesia |
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What is the major inhibitory neurotransmitter in the CNS?
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GABA
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How is GABA made?
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From glutamate using GAD (glutamic acid decarboxylase) (w/ PP(vit B6))
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What is GABA release dependent on?
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Ca
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Where does GABA work?
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presynaptic autoreceptors and postsynaptic receptors
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Which GABA receptor(s) are ionotropic, increase chloride ion conductance?
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GABA-A and GABA-C
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Which GABA receptor(s) are metabotropic?
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GABA-B
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Active GABA uptake into presynaptic endings and glia is dependent on which ion?
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Na
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What does GABA-T do?
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Turns GABA into glutamine in mitochondria
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Which GABA receptor is both presynaptic and postsynaptic?
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GABA-B
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Which GABA receptor has multiple binding sites for neuroactive drugs?
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GABA-A
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Name 3 agonists for GABA-A receptors?
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1. Benzodiazepines- allosterically enhance GABA binding
2. Ethanol- enhances Cl channel opening 3. General anesthetics- bind hydrophobic site |
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Name 4 GABA-A antagonists; what can they cause?
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1. bicuculline
2. picrotoxin 3. pentylenetetrazol 4. penicillin seizures |
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Describe how GABA-B presynaptic receptors work
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G/Go --> block Ca channel --> dec presynaptic Ca --> inhibit transmitter release
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Nama a GABA-B presynaptic receptor agonist
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Baclofen- centrally acting muscle relaxant (spasmolytic)
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Describe how GABA-B postsynaptic receptors work
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G/Go --> open K channel --> hyperpolarizes neuron --> inhibits depolarization
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What is 5-hydroxytryptamine, 5HT
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Serotonin
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How is serotonin made?
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tryptophan --> 5-hydroxytryptophan --> 5-hydroxytraptamine
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Which areas of the CNS are involved with serotonin?
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Raphe nuclei send serotonergic projections to --> cerebral cortex, limbic system, and diencephalon
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What is serotonin release dependent on?
What increases the release? |
Ca
fenfluramine |
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What types are most of the 15 different serotonin receptors?
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pre and postsynaptic metabotropic (GPCRs)
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What terminates action of serotonin? What can stop that?
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active re-uptake into presynaptic terminals
SSRIs- fluoxetine, etc |
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What enzymatically degrades serotonin
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MAO
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How does LSD work?
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inhibits firing of serotonin neurons --> reduces release of 5HT --> acts at presynaptic autoreceptors and modulates serotonin release
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What is the excitatory neurotransmitter in the spinal cord?
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ACh
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Name two nicotinic receptor (ionotropic) agonists
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ACh
nicotine |
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Name one nicotinic receptor (ionotropic) antagonist
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curare
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Name 2 muscarinic receptor (metabotropic) agonists
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ACh
muscarine |
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Name 2 muscarinic receptor (metabotropic) antagonists
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Atropine
Scopolamine |
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What may serve as a retrograde transmitter from postsynaptic to presynaptic cell?
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NO
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How is NO made?
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Arginine --> NO + citrulline
via NO synthase |
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What activates NO synthase?
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calcium-calmodulin
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How can NO enhance transmitter release?
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activates heme-containing gyanylyl cyclase
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Where in the CNS is NO involved?
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cerebellum
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Name two correlations to CNS NO?
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1. learning and memory
2. ischemic neuronal damage |
