Term
| A neurotransmitter is inhibitory or excitatory depending on ______ |
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Definition
| the type of receptor to which it binds |
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Term
| Can a given neurotransmitter have different effects? |
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Definition
| yes! (because it can bind to different kinds of receptors) |
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Term
| Do some receptors have channels? |
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Definition
| yes! (so people use the terms interchangeably sometimes) |
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Term
| What is another name for ionotropic channels? |
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Definition
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Term
| Can metabotropic receptors bind a neurotransmitter like ionotropic channels? |
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Definition
| yes! (sometimes can work with the same ones such as ACh) |
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Term
| Can you have ionotropic or metabotropic receptors that are presynaptic too? |
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Definition
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Term
| Do ionotropic or metabotropic receptors tend to be much closer to where neurotransmitter is released? |
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Definition
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Term
| Do ionotropic or metabotropic receptors tend to be more outside of the synaptic cleft? |
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Definition
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Term
| Difference between ionotropic vs metabotropic receptors: speed of effects |
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Definition
ionotropic = rapid effects
metabotropic = slow effects |
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Term
| Difference between ionotropic vs metabotropic receptors: speed of termination of effects |
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Definition
ionotropic = rapid termination of effects
metabotropic = slow termination of effects |
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Term
| Difference between ionotropic vs metabotropic receptors: relationship between action & response |
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Definition
ionotropic = 1:1 relationship between action & response
metabotropic = >1:1 amplification of response |
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Term
| Difference between ionotropic vs metabotropic receptors: range of effects |
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Definition
ionotropic = range of effects limited by receptor
metabotropic = diverse possible effects from a single transmitter |
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Term
| What does nAChR stand for? |
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Definition
| "nicotinic acetylcholine receptors" |
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Term
| ______ is also a ligand for the nAChR family of ACh receptors |
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Definition
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Term
| Why do scientists use the torpedo fish that kill their prey by stunning them to study nAChRs? |
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Definition
| underside has tons & tons of ACh receptors...super dense --> allows scientists to really study these receptors (easier to purify for them because they're so dense) |
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Term
| In nAChRs, the ACh binding site is ______ |
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Definition
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Term
| nAChRs have a "gate" that ______ when ligand binds |
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Definition
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Term
| 2 different main types of nAChRs |
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Definition
1. nicotinic receptors found on muscles
2. nicotinic receptors found on neurons |
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Term
| Is the extracellular domain where neurotransmitter binds on muscle nAChRs complicated or simple? |
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Definition
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Term
| Is the intracellular domain of muscle nAChRs as complicated as the extracellular domain? |
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Definition
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Term
| 2 ions mainly passed by muscle nAChRs |
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Definition
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Term
| The resting membrane potential of muscle nAChRs is reliant on both _____ & ______ |
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Definition
| sodium & potassium (but it isn't quite the average between the two because there is unequal conductance for each ion) |
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Term
| 4 different types of subunits of muscle nAChRs |
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Definition
1. two alpha
2. one beta
3. one delta
4. one gamma |
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Term
| Muscle nAChRs require at least two ______ subunits |
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Definition
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Term
| different subunit makeup of muscle nAChRs --> ? |
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Definition
| different functions of the proteins |
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Term
| Each neuronal nAChR has ______ TMRs |
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Definition
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Term
| ______ is the domain that forms inside of the pore of neuronal nAChRs |
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Definition
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Term
| homomeric neuronal nAChRs |
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Definition
| all five subunits are the same |
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Term
| heteromeric neuronal nAChRs |
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Definition
| not all five subunits are the same |
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Term
| Difference in nomenclature between neuronal nAChR subunits & domains |
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Definition
subunits = the ones with the Greek letters
domains = M1 - M4 (within each subunit) |
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Term
| What are you looking for when you look at a dissociation constant graph for muscle & neuronal nAChRs? |
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Definition
| graph looking at how much concentration you need of ACh to bind 50% of your receptors |
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Term
| Why do muscle nAChRs need a higher concentration of ACh than neuronal nAChRs to activate muscle? |
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Definition
| they have a lower affinity |
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Term
| Will neuronal nAChRs have a higher or lower dissociation constant than muscle? |
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Definition
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Term
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Definition
| a compound that elicits the same biological effect(s) as the natural ligand when it binds to a receptor |
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Term
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Definition
| a compound that attenuates the effect of an agonist when bound to a receptor |
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Term
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Definition
| binds to the same site as the agonist, but does not activate the receptor |
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Term
| non-competitive antagonist |
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Definition
| binds to the receptor at a different site from the agonist, but prevents activation of the receptor |
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Term
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Definition
| binds non-covalently to the receptor, so can come off the receptor by "washing off" |
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Term
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Definition
| binds covalently to the receptor, so cannot be displaced by either competing ligands or "washing off" |
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Term
| What does it mean that the binding of a ligand is probabilistic? |
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Definition
| the binding frequency depends on the concentration of the ligand |
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Term
| 4 main symptoms of the myasthenia gravis disease |
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Definition
1. compromises specific groups of striated muscle
2. oculomotor disturbances & oropharyngeal muscle weakness (limb weakness in about 10% of patients)
3. course of the disease is variable, but generally progressive
4. severity of symptoms fluctuates throughout the day (strength decreases with exercise) |
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Term
| What is the most common primary disorder of the neuromuscular junction? |
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Definition
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Term
| What type of disease is myasthenia gravis? |
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Definition
| an autoimmune disease of the NMJ |
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Term
| 3 main treatments for myasthenia gravis disease |
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Definition
1. cholinesterase inhibitors (the goal is to increase the amount of transmitter in the cleft)
2. Thymectomy (long term treatment to reduce production of anti-ACh receptor antibodies)
3. plasma exchange (short term treatment to reduce antibodies for those who have a sudden worsening of symptoms or to improve recovery from other procedures such as surgery) |
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Term
| difference between non-NMDA & NMDA ionotropic glutamate receptors: agonist |
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Definition
non-NMDA = AMPA & kainate
NMDA = NMDA |
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Term
| difference between non-NMDA & NMDA ionotropic glutamate receptors: conductance |
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Definition
non-NMDA = low conductance
NMDA = high conductance |
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Term
| difference between non-NMDA & NMDA ionotropic glutamate receptors: ion permeability |
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Definition
non-NMDA = sodium, potassium (some calcium)
NMDA = sodium, potassium, calcium |
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Term
| difference between non-NMDA & NMDA ionotropic glutamate receptors: gating speed |
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Definition
non-NMDA = fast gating speed (like voltage-gated)
NMDA = slow gating speed |
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Term
| difference between non-NMDA & NMDA ionotropic glutamate receptors: magnesium block |
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Definition
non-NMDA = no magnesium block
NMDA = magnesium block |
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Term
| classes of ionotropic glutamate receptors are differentiated by ______ |
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Definition
| the type of ligand they bind |
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Term
| In order for NMDA channel to have current, ______ must be present & bind (no matter what!) |
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Definition
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Term
| ______ can bind to a site inside of the NMDA channel & block the channel |
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Definition
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Term
| How does magnesium get pushed out of the NMDA pocket? |
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Definition
| once membrane potential depolarizes pretty high (~ -20) |
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Term
| Differences in the IV plot of NMDA receptors based on if magnesium is present or not |
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Definition
if there is no magnesium present = you get basically a normal linear IV plot
if magnesium is present = at hyperpolarized potentials there is virtually no current; once you reach a sufficient membrane potential, the current becomes pretty linear & normal looking |
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Term
| coincidence detector for NMDA receptors |
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Definition
| you need both glutamate present/bound & a depolarized enough membrane potential |
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Term
| ______ that flows through NMDA receptor channels is a big deal |
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Definition
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Term
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Definition
| cells get too excited & cell dies |
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Term
| Ionotropic GABA & glycine receptors have mostly ______ reactions |
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Definition
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Term
| Both GABA & glycine receptors have ______ subunits |
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Definition
|
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Term
| ______ receptors have a glycine binding site & pass chloride |
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Definition
|
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Term
| 2 main categories of GABA receptors |
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Definition
1. GABA "A" (the ionotropic ones)
2. GABA "B" (the metabotropic ones) |
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Term
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Definition
drugs that act on GABA "A"; bind to a different site than where GABA binds
*you need GABA to trigger opening even if BZ is bound* |
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Term
| GABA receptors pass _____ in |
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Definition
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Term
| Cell resting at a more positive membrane potential than chloride equilibrium potential: influx of chloride will cause _____ |
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Definition
|
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Term
| Why can you really see the difference of the effect of chloride influx at various resting membrane potentials? |
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Definition
| chloride reversal potential is about equal to the resting membrane potential |
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Term
| Cell resting at a more negative membrane potential than chloride equilibrium potential: influx of chloride will cause _____ |
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Definition
|
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Term
|
Definition
| chloride having an effect on resting membrane potential draws membrane potential down lower than when just sodium & potassium were in play |
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Term
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Definition
1. having chloride channels increases conductance (reduces resistance)
2. if current is the same, then voltage has to go down (V = I*R)
3. results in a smaller EPSP |
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Term
| GABA "A" receptors are hyperpolarizing if Ecl ? Vrest |
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Definition
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Term
| GABA "A" receptors have a shunting effect if Ecl ? Vrest |
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Definition
| Vrest < Ecl < action potential threshold |
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Term
| GABA "A" receptors have an excitatory effect if Ecl ? action potential threshold |
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Definition
| Ecl > action potential threshold |
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