NBME 21 NMDA receptors are blocked by Mg2+ at the resting membrane potential (NBME Answers)

NBME 21 Answers

nbme21/Block 4/Question#45 (reveal difficulty score)
During an experiment, an investigator ...
NMDA receptors are blocked by Mg2+ at the resting membrane potential 🔍 / 📺 / 🌳 / 📖
tags: pharm neuro magnesium repeat

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submitted by ∗niboonsh(409)

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.wm:zvsoauweh4ow=.2/?h-cQt/uvbwttpHcDuyt/wo if ur yalz ilke ,em tsih si a oodg srrefeehr oedvi

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d_holles Amazing video dude. Somehow never learned this in neuro lol. +7

aag Awesome video! Is this why you can give Mg2+ to eclampsia patients, because if so, mind goddamn blown. +4

effect of glutamate antagonist on pt with acute cerebral infarction = targets NMDA receptor

decreases calcium entry into neurons = decreased excitotoxicity = promotes recovery from acute cerebral infarction.

+/- namesthegame22(11)

+5 upvote downvote
submitted by ∗cantaloupe5(87)

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iTsh one wsa ikcytr but I hiktn uoy ovuldc’e ndeo hist noe woithut nwogdeelk of AMDN ocreers.tp meSt oltd ouy ahtt gtmaultea staveciat hbot on-DnAMN adn ADMN rceptosre but ti vdectiaat lony AoDnNn-M trsreeocp ni eth ylrea pa.she tahT naems ADNM rctserpeo aiecttva rteaf nnoDNAM- cs.erortpe tahT emasn tmogehnis wsa aildegny MAND ptoerecr ctvgniaita dna eht nloy ewsnra htta amed senes as teh gM hiiitnginb DMAN at igrnets tepn.oalit ceOn eht lelc is pedrildozea by MNnDn-Ao per,cterso NDAM rcsteerpo nca be .avdietatc

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hungrybox I forgot/didn't know this factoid and narrowed it to the correct answer and a wrong answer. Guess which one I chose? +15

yotsubato >That means something was delaying NMDA receptor activating and the only answer that made sense as the Mg inhibiting NMDA at resting potential. What makes the fasting gating kinetics choice incorrect then? +5

imgdoc NMDA receptors are both voltage gated and ligand gated channels. Glutamate and aspartate are endogenous ligands for this receptor. Binding of one of the ligands is required to open the channel thus it exhibits characteristics of a ligand channel. If Em (membrane potential) is more negative than -70 mV, binding of the ligand does NOT open the channel (Mg2+ block on the NMDA receptor). IF Em is less negative than -70 mV binding of the ligand opens the channel (even though no Mg2+ block at this Em, channel will not open without ligand binding. Out of the answer choices only NMDA receptors blocked by Mg2+ makes sense. Hope this helps. +8

divya sweet explanation imgdoc +

lovebug really~~~ sweet. thankyou :) +

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submitted by ∗sweetmed(157)

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At rigtesn emrnambe ntoliepat eht DANM strreocep rea cbldeko by g.M+2 eTh vgelaot dntnpedee Mg+2 cbolk si eilreevd npou dpoolitziraean fo eht ptnospsa-ticy mamebern . hTe inlgda ednepetdn vaioittanc fo teh NDMA oerctpre usiererq ctva-iocoiatn by two nial,sdg ymanel auatteglm and cignye.l

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+0 upvote downvote
submitted by ∗okokok1(38)

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An trmoptian aeedlrt lnalccii opntaiaclpi si ne:rbmergemi anviOra ttreaoam dna ihrte coiisnstasao :wtih Ai-ANntDM rrpteeoc ltaiehcpes.ni shiT rspetnes a:s icirythcaPs icudars,btne emyrmo ecstid,fi eizues,rs seisdskn,iay noaotmicu it,abyslntii gagleuna ntu.yisdocnf

AF: ;2020 gp 822

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-1 upvote downvote
submitted by vlodkadrinker(7)

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tdo'n froegt otuab eth gM lcob!k . . . . . .

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chandlerbas https://www.youtube.com/watch?v=-mHgPfXHzJE +3

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