Problem 3 Flashcards

1
Q

Postsynaptic Potential

A
  • brief changes in membrane potential of the postsynaptic cell caused by the release of neurotransmitters

Whether cell excites or inhibits is dependent on the neurotransmitter

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2
Q

Excitatory postsynaptic potential (EPSP)

A
  • pushes the postsynaptic cell closer to threshold for AP

- -> Depolarizing

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3
Q

Synaptic delay

A
  • Delay between arrival of Ap at axon terminal + creation of a postsynaptic potential
  • Reflects the time needed for neurotransmitters to diffuse into synaptic cleft
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4
Q

Inhibitory postsynaptic potential (IPSP)

A
  • moves postsynaptic cell away from threshold for AP
    • -> Hyperpolarizing
  • increase of resting membrane potential
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5
Q

Spatial summation

A

The simultaneous summation of potentials ( E / IPSP ) from different locations ( dif. postsyn. membr. ) across the cell body

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6
Q

Temporal summation

A
  • not absolutely simultaneous

- -> the closer they are in time - the greater the overlap

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7
Q

Role of distance in EPSPs

A

Simultaneous EPSPs from synapses closer to the axon hillock will produce a larger sum than those farther away

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8
Q

Ligand

A
  • molecule of the perfect/correct shape for a receptor
    • -> Schlüssel-Schloss Prinzip

-can activate or block the receptor

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9
Q

Endogenous ligands

A

Neurotransmitters/Hormones made inside the body

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10
Q

Exogenous ligands

A

Drugs/Toxins that work as neurotransmitters from outside the body

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11
Q

Agonist

A

Molecule that acts like a neurotransmitter

 --> high efficacy
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12
Q

Antagonist

A

Molecule that prevents the action of a transmitter

 --> low efficacy
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13
Q

Ionotropic receptors

A

control ion channels directly

–> when bound, ion channels open immediately

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14
Q

Metabotropic receptors

A

activate G-Proteins, which in turn activate ion channels

–> indirect control of ion channel

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15
Q

G-protein

A

molecule,

  1. either directly opens ion channel
  2. or activates another chemical signal which then opens the ion channel
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16
Q

Degradation

A

Special enzyme breaks transmitter down into pieces

  --> products are recycled to make more of the transmitter in the axon terminal
17
Q

Reuptake

A

Special receptors of the transmitter are located in the presynaptic membrane and bring the transmitter back inside its the help of transporters

18
Q

Convergence

A

Type of neural circuit

  • many cells send signals to one
19
Q

Divergence

A

Type of neural circuit

  • one cell sends signals to many
20
Q

Binding Affinity

A

the degree of chemical attraction between ligand and receptor

21
Q

Efficacy

A

Propensity (Neigung) of a ligand to activate the receptor to which it is bound

22
Q

Partial Agonist

A

A partial agonist is a drug that has a very
high affinity for a particular receptor but activates that
receptor less than the normal ligand does

23
Q

Division of a Synapse

A
  1. Presynaptic Membrane = usually axon terminal
  2. Synaptic Cleft = gap between pre- and postsynaptic membrane
  3. Postsynaptic Membrane = usually dendrite
24
Q

Synaptic Transmission

A
  1. AP arrives at axon terminal
  2. Depolarization opens voltage-gated Ca2+ channels in the membrane of axon terminal
    • -> Ca2+ ions enter the terminal
  3. Exotysis= Ca2+ causes vesicles to fuse with presynaptic membrane, rupture, release transmitter into synaptic cleft
    • -> mediated by V/T-Snare and Synaptotagmin
  4. transmitter molecules cross the cleft to bind to special receptors in postsynaptic membrane
  5. ion flow creates a local E/IPSP in the postsynaptic neuron
  6. Synaptic transmitter is either inactivated (Degradation) or removed (Reuptake) from synaptic cleft by transporters
  7. Synaptic transmitters may also activate presynaptic autoreceptors
25
Q

V-Snare

A

attached to the vesicle

26
Q

T-Snare

A

attached to presynaptic membrane

27
Q

Action of V/T Snares

A
  • Their Snares attach

- -> Vesicle is now docked on the presynaptic membrane and ready to be released

28
Q

Function of Synaptotagmin

A

Triggers final fusion of the vesicle with the presynaptic membrane