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31 Cards in this Set
- Front
- Back
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What's the main difference in effects between ligand receptors and g protein coupled receptors?
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Ligand have rapid, short-acting responses while g protein has slow potentials with long-term effects.
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What causes excitatory depolarization (ion-wise)?
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More Na+ in or less K+ out
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What causes inhibitory hyperpolarization (ion-wise)?
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More K+out, more Cl- in or less Na+ in
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What are the 4 criteria for being a neurotransmitter?
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1. Presence (in the presynaptic terminal)
2. Release (in response to depol, Ca2+ dependent) 3. Identity of action (direct application effects = presynap stim) 4. Removal (1+ mechanisms for elimination) |
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What synapses are cholinergic?
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Neuromuscular, autonomic ganglia, parasymp postgang neuroeffector, sweat glands, between symp pregang and adrenal chromaffin cells, and certain CNS.
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What synapses involve norepi (noradrenergic)?
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Postgang sympathetics and certain CNS.
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What synapses involve epinepherine?
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Certain CNS.
Also a hormone released from chromaffin cells. |
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What synapses involve dopamine?
(dopaminergic) |
Postgan sympathetics in the kidney and certain CNS.
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Where is nonadrenergic noncholinergic transmission typically found?
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Enteric nervous system
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What types of transmitters are involved in nonadrenergic noncholinergic transmission and cotransmission?
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adenosine 5’-triphosphate (ATP)
vasoactive intestinal peptide (VIP) neuropeptide Y (NPY) leutinizing hormone releasing hormone (LHRH) 5-hydroxy tryptamine (5-HT or serotonin) nitric oxide (NO) gamma-amino butyric acid (GABA) substance P dopamine |
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Structure of muscarine?
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Structure of atropine?
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Structure of dopamine?
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What's cool about NO?
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Cotransmitter at inhib ENS and neuromuscular junctions (especially important at sphincters). Synthesized by NO Synthase when stimulated by Ca2+, can cross membrane without vesicles.
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How's ACh made? What's the rate-limiting step?
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Synthesized by choline acetyl-transferase in cytosol from acetylCoA and choline. Rate limiting step = choline uptake from ECM via high affinity transporters.
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How is ACh broken down?
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By Acetylcholinesterase in the synaptic cleft
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What compound blocks choline uptake? (synthesis)
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Hemicolinium
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What compound inhibits the vesicular ACh transporter? (storage)
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Vesamicol
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What compound blocks exocytosis of ACh by modifying docking proteins and preventing synaptic vesicle fusion with the presynapatic nerve terminal? (release)
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Botulinum Toxin
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What compound is a nicotinic agonist?
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Nicotine (used in Alzheimer's tx)
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What compound is a muscarinic agonist?
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Bethanacol
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What compound is a neuronal nicotinic antagonist?
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Trimethaphan (blocks ganglionic transmission - major effect = vasodilation)
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What compound is a muscular nicotinic antagonist?
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d-tubocurarine (paralyzes somatic muscle)
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What compound is a muscarinic antagonist?
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Atropine (used locally to dilate the eye and systemically to increase HR and cardiac output)
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What compound inhibits acetycholinesterase? (disposition)
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physostigmine (used to tx myasthenia graves and glacoma)
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In the synthesis of norepi, what is tyrosine converted to? What is the enzyme involved?
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Tyrosine is converted to DOPA via Tyrosine Hydroxylase in the cytosol (*rate-limiting step*)
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In the synthesis of norepi, what's DOPA converted to? What's the enzyme involved?
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DOPA's converted to Dopamime via DOPA decarboxylase in the cytosol
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What's dopamine converted to? What's the enzyme involved?
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Dopamine's converted to norepi via Dopamine Beta-hydroxylase in the vesicle (*released into cleft when the neurotransmitter is*)
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What's alpha2 receptor's major function?
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Located at the presynaptic terminal, provides negative feedback to the presynaptic neuron to stop the release of neurotransmitter.
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Which of the beta receptors has the highest affinity for norepi?
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Beta1
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What enzymes metabolize epi and norepi? What are they metabolized into?
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MAO and COMT metabolize them to vanillylmandelic acid. (dopamine's metabolized to homovanillic acid)
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