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34 Cards in this Set
- Front
- Back
What is the Nernst equation (at room temperature)?
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Eion=58/zlog[ion-out/ion-in]
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Assuming outside of cell is up, which direction is the battery when Eion<0? Eion>0?
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When Eion<0, positive end of battery faces up (because positive ions move outward). When Eion>0, the plus side faces down
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In normal neurons, which ion has a larger concentration inside than outside?
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K+
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Draw a circuit
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ok :(
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Describe the different types of recording in the patch clamp method
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Whole-cell recording: cytoplasm is continuous with pipette interior
Inside-out recording: cytoplasm domain accessible Outside-out recording: ??? |
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Describe three properties of Na+ channel currents
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1) inward
2) rapid onset after depolarization 3) rapid inactivation |
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Be able to do I-V curves
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ok :(
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Name and describe three classes of ion channels
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1) leak channels - conductance is constant
2) voltage-gated channels - conductance depends on voltage 3) ligand-gated channels - conductance changes upon binding of ligand |
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How is outward rectification represented on an I-V curve?
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Slope is greater above x-axis than below.
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What happens during the threshold phase of an action potential?
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Once the membrane depolarizes enough (to ~-50mV), it triggers the opening of voltage-gated K+ channels
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What happens during the rising phase of an action potential?
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Sodium channel opens, Na+ flows into the cell. This drives the membrane to peak, which is near the ENa. Membrane permeability for Na increases significantly over K at this point.
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What happens during the falling phase of an action potential?
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Voltage-gated K+ channels open, start pushing membrane potential back down to Ek. Na channels start to deactivate
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What happens during the undershoot phase of an action potential?
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K+ condutance higher than at rest, membrane potential approaches Ek (which is lower than rest). As K channels close, the membrane returns to resting potential.
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[Paper] Before doing the study, what was not known?
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Capsaicin application to nociceptive sensory neurons increases membrane permeability to cations.
(i'm sure there are other stuff we didn't know but this was a clicker q) |
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[Paper] What effect does VR1 expression have on HEK293 cells?
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VR1 expression is sufficient for capsaicin to elicit calcium entry into HEK293 cells.
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[Paper] VR1 shows activity in response to what?
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Heat (could explain why spicy things feel hot)
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Name each type of synapse
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Excitatory, Inhibitory, Modulatory
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What would the result of a Ca2+ channel blocker on a presynaptic terminal on the post-synaptic membrane?
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There would be no change in membrane potential as there would be no neurotransmitter released
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Which ion channel is required for an action potential?
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Sodium! Without that, no rising phase.
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If Erev=Ek, what can be said about the channels of that membrane?
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Only K-selective channels are open.
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What effect does the binding of a neurotransmitter have on a channel?
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It affects the conductance (g) of that channel.
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In what circumstance is a channel inhibitory?
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If the Erev for that channel is below threshold, then opening that channel is inhibitory, or IPSP.
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Name two excitatory neurotransmitters
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Acetylcholine and Glutamate
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Name two inhibitory neurotransmitters
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GABA and Glycine
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How does nicotine act on the nicotinic acetylcholine receptor?
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Nicotine is a partial agonist. It increases HR, BP, dizziness, etc.
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What does alpha-bungarotoxin do?
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Binds irreversibly to NAcR and prevents activation (causing paralysis)
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What is the metabotropic receptor for ACh called, and what role does it play?
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Muscarinic receptor, plays a modulatory role and is generally poorly understood
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Name and describe the two major glutamate receptor types
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AMPA: fast, ionotropic, non-selective cation channel, similar to KianateNMDA: slower, metabotropic, passes Ca2+ to cause various downstream effects, involved in memory formation
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NMDA receptor is voltage-dependent for what cation?
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Mg2+. At low Vm, current (I) approaches 0
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Identify and classify the main GABA receptors
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GABA(a) and GABA(c)- ionotropicGABA(b) - metabotropic
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How do benzos act as a sedative?
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They bind to GABA(a) receptor and potentiate (inhibitory) activity
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Which GABA receptor is a GPCR that leaks to inward rectifying K+ channels?
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GABA(b)
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How are biogenic amines packaged?
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vesicular monoamine transporters (VMAT1 and VMAT2)
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What makes endocannabinoids unique?
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They can act as a retrograde signal from postsynaptic cell to presynaptic cell. |