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

NBME 21 Answers ↦

nbme21/Block 4/Question#45 (67.1 difficulty score)
During an experiment, an investigator ...
NMDA receptors are blocked by Mg2+ at the resting membrane potential🔍,📺
tags: neuro magnesium pharm

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+48
submitted by niboonsh(358),

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hsmewtQtw/.4H/oo.:w2=vaucw-otztDbc?u/wpuyhv if ru yazl leki me, tish is a oodg reehsefrr odevi

d_holles Amazing video dude. Somehow never learned this in neuro lol. +6

aag Awesome video! Is this why you can give Mg2+ to eclampsia patients, because if so, mind goddamn blown. +2

+5
submitted by cantaloupe5(77),

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ihTs eno saw ctyirk ubt I iknht yuo ou’vdcle eodn tsih noe uhtiowt onlegedkw fo MNDA rtsoc.eper etmS odlt ouy thta tmelauatg catsaivte thbo MnDonNA- and DMNA eprrtosce but ti detcaivat lnyo nDM-nAoN esrecoptr ni the aleyr s.eaph athT ensma ANMD rrtecespo aeiacttv aerft Ao-NMnDn e.rtosrcpe That smean ioghentms wsa ylneidga NAMD ecprtero tatinviacg and teh noyl snwaer htat emda esnes as hte Mg niinihtgbi DMNA ta intsrge oan.tlitep eOnc the ecll si eplrdozadei yb -DNAonnM roescrtp,e DANM ptrcesreo nac eb vtae.atdic

hungrybox I forgot/didn't know this factoid and narrowed it to the correct answer and a wrong answer. Guess which one I chose? +14

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. +6

divya sweet explanation imgdoc +

lovebug really~~~ sweet. thankyou :) +

+3
submitted by sweetmed(144),

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tA trngise manmeber eloatnpit teh NDAM setrcoepr era blcdkoe by .+M2g The tgeaovl eenneddtp g+2M klcob si eveilred oupn ionaadzipoelrt of eth cpioy-satptsn mbneeram . ehT glidna edpdnteen tonitvaiac fo eth DAMN eprercot uerirseq vccaiton-aito yb two dn,sglia ymenla tulamaget adn .gynelci

+0
submitted by okokok1(12),

An important related clinical application is remembering: Ovarian teratoma and their associations with: Anti-NMDA receptor encephalitis. This presents as: Psychiatric disturbance, memory deficits, seizures, dyskinesias, autonomic instability, language dysfunction.

FA: 2020; pg 228

-1
submitted by vlodkadrinker(7),

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tdn'o ofetgr oautb eth gM kbolc! . . . . . .

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