Cellular and molecular neuroscience (UA_2012FBDBMW)
Institution
Universiteit Antwerpen (UA)
In this summary (based on my own notes and PPT) you can find the chapters that are given by Prof. De Schutter.
Color code:
-Purple= 1.
-Dark pink = 1.1.
-Light pink = 1.1.1.
-Green= 1.1.1.1
- Blue= 1.1.1.1.1
Important abbreviations:
- N = neuron
- B = brain
- !!! = important
- NT =...
Cellular and molecular neuroscience (UA_2012FBDBMW)
All documents for this subject (2)
1
review
By: roberto777torres • 10 months ago
Seller
Follow
evevlaemynck
Reviews received
Content preview
LIMITATIONS OF HH-MODEL CELLULAR & MOLECULAR NEUROSCIENCE (DE SCHUTTER): FUNCTION ION CHANNELS
> single channel gating complex FIRING DYNAMICS CAUSED BY DIFFERENT CHANNELS firing pattern N -> interaction ≠ IC
> inactivation not purely voltage- + depends strongly on membrane potential:
dependent > thalamic cells: burst or transfer mode I. IA: give current injection at -55mV
> not all current Ohmic → transfer = awake / burst = sleep -> A current rapidly inactivates ->
> B-stem: deep polarization AP that slowly repeat at -75mV -> A current
SINGLE CHANNEL recover completely inactivated -> takes a
CURRENTS: COMPLEX while to spike: gives delay in spike
≠ firing patterns caused by interaction many II. IL,C & h in bursting N: IL activates IC
GATING channel -> repolarization cell -> activate Ih
Na+ & K+ have totally ≠ properties → have HVA & LVA channels = high/low threshold -> brings cell back -> repeat
INACTIVATION NOT (nowadays wrong nomenclature) III. IM & spike accommodation: if you
→ each channel has whole bunch of sub- block IM then cell can spike again
PURELY VOLTAGE- types -> many firing options
DEPENDENT
channels has 2 gates:
FIRST NEW CHANNEL:
> activation gate: in rest closed & A-CURRENT
opens when activated MODERN MODELS OF Na+ & K+ first discovered channel after HH
> inactivation gate: cytoplasmatic = K+ channel
ball that floats in/out channel GATING = LVA: activates at low threshold +
→ !!! first need to activate channel modern models of Vandenberg & Bezanilla: ≠ rapidly inactivates by A-type current BUILDING BLOCK
to be able to inactivate it for Na+ & K+ → allows N to fire slowly APPROACH
→ each ion has 1 open state & multiple closed → when AP stops there’s de- you begin with HH & spike fast
states activation A-current → then start adding ≠ channels: will
→ models are hard: statistically most result in changes in AP & firing:
correct model, but it’s not guaranteed
OVERVIEW ION CHANNELS
> +IA = delayed firing
to be correct > +ICa = Ca2+ channel: enhances
repolarization
> +IT = binary behaviour: the lower
potential, the more firing
>+IAHP = get cumulative response:
in first spikes it doesn’t do a lot,
but after few spikes it adds up
NEURONS HAVE ≠ FIRING
experiment confirmed that inactivation
is due to ball in cytoplasm: PATTERNS
> WT: have clear inactivation ≠ types of N have ≠ firing patterns:
> ball deleted: no inactivation > pyramidal cells = most studied: regular &
> mutant, but lose ball: have weak burst mode
inactivation, but not same as WT > cerebellar cells: fire faster & higher
, Ih MORE IN DETAIL Ca2+ CHELATORS ACTION POTENTIAL
= hyperpolarizing active channel: = molecules that bind Ca2+
PROPAGATION
> reversal potential = -35mV → most popular ones: EGTA & BAPTA
→ when you voltage clamp at ≠ → affinity the same, but binding speed ORIGIN OF AP
levels you can see that the ≠: BAPTA faster where AP originated: axon, axon segment,
more depolarized cell is, the axon initial segment, nodes of Ranvier,...?
more Ih is activated → Stuart & Sakmann investigated this
> spike interval slowly activates
→ AP originates in begin axon & back-
Ih & brings channel out of hyper-
propagate into dendrite
polarization
> recently specific Ih blockers
discovered
Ca2+ ACTIVATED Ca2+ METABOLISM IN N
K+ CHANNELS Ca2+ !!!! signalling molecule: in N very controlled
→ [Ca2+] very low: specialised Ca-buffers
bind free Ca2+ & put in intracellular Ca2+
stores (=mitochondria & ER)
→ 2 ways to release Ca2+:
> IP3-R: activated by metabotropic
glutamate R (so via synaptic signals)
> RyR = ryanodine R
→ also pumps: PCMA & SERCA -> ATP-
dependent exchange of Na+ & Ca2+
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller evevlaemynck. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.33. You're not tied to anything after your purchase.
