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Flashcards in Synaptic transmission Lec06 Deck (54):
1

EPSPs increase the probability for an action potential to be generated because they let _____ into the cell body depolarizing the cell. 

sodium

2

IPSPs decrease the probability for AP by

letting K out or chlorine in

3

direction of electrical synapses

bidirectional

4

electrical synapses are connected via 

gap junctions (made of connexins)

5

what kind of pores do electrical synapses have? what do they let in

 very large pores for unselective ion diffusion

6

what triggers vesicle fusion?

influx of ca through voltage gated ca channels

7

what happens if you have no Ca voltage gated channels

no NT release

8

what happens if you ↓ external [Ca] 

 ↓ # of vesicles = ↓ postsynaptic potential

9

Ionotropic receptors - ligand-gated ion channels respond in ____ 

msec

10

Metabotropic receptors - G-protein-linked receptors that respond in ___

sec/min (growth factor recpeotrs take even longer)

11

how does inactivation of chemical nt take place 

 via reuptake, glial uptake, diffusion, or enzymatic breakdown

12

what are the advantages of chemical synapses 

directionality, amplification, plasticity, summation

13

what is facilitation 

 short-term synaptic plasticity

14

what does facilitation involve?  what does it result in?

 multiple action potentials in a short time (<50 msec) = ↑↑ in synaptic strength

15

describe the 2nd epsp after facilitation 

2nd EPSP larger than the 1st  because Ca clearance is slower than Ca entry into cell

16

how large are small molecule nt

50 nm diameter

17

how are small molecule NT stored?

in clear vesicles

18

some ___ are docked at active zones

small molecule nt

19

docked small molecule nt are released by 

local ca influx

20

how are neuropeptides stored?

dense core vesicles

21

what is required for neuropeptide release? 

high frequency stimulation

22

Vesicle release is quantal/discrete: each vesicle = 

1 mini end plate potential

23

how do miniend plate potentials cause depolarization? 

Many MEPPs make up the endplate potential, EPP, causing depolarization

24

how can you get larger mini end plate potentials?

more ach or more veiscles

25

cable theory

neuron changes in synapse potential decrease with time and space

26

___ and ___ determine probability of an action potential due to leakage

Temporal and spatial summation

27

EPSP & IPSP amplitude & direction depend on 

ion permeability and membrane voltage

28

NMDA is slower, Mg-blocked, but allows ___

Ca entry

29

GABA__ receptors are ligand-gated channels

 A

30

GABA A receptors make __ with CL- ions

fast ipsp

31

GABA A receptors have ___ subunits

5

32

what increases the GABA A channel open time

a barbituate + gaba (increases the channel open time)

33

GABA __ receptor are g protein linked and slower

B

34

how many synapses does each neuron integrate ifnormation from?

multiple

35

what are the 4 criteria for chemical NTs?

1) present in presynaptic terminal.
2) released in response to stimulation – release must be Ca2+ dependent.
3) specific receptors for the neurotransmitter must be present on the postsynaptic cell.
4) mechanism to inactivate neurotransmitter must be present (reuptake, enzymatic breakdown).

36

what type of flow occurs through gap junctions in electrical synapses

passive flow

37

how common are electrical synapses?

they are present in cns but less common than electrical synapses

38

 brainstem neurons that regulate breathing are synchronized by 

electrical synapses.

39

chemical syanspes provide potentiation for

1. excitation and inhbiiton

2. plasticity and remodeling

40

what drives Ca into the presynatpic membrane

concentration gradient (more ca outside)

electrical gradient 

41

what does facilitation result from?

prolonged elevation of presynaptic Ca

42

Synaptic facilitation is a rapid increase in ___

synaptic strength

43

. Facilitation is not observed if __

two APs arrive far apart in time 

44

how many chemical transmitters can a single neuron release?

many

45

what is the range of time courses of chemical transmitters?

msec to days

46

trnasport of neuropetide vesicles is dependent on ___

ATP

47

what is the postsynaptic density

an electron dense area with many receptors in the postsynaptic target cell

48

 The MEPPs result from the discharge of the contents of 

a single synaptic vesicle

49

post synaptic potentials resutl from 

conductance changes to

A image thumb
50

synaptic potentials are passive events that become progressively smaller at

greater distances ro

51

why dont dendrites transmit AP?

1. they do not contain many Na+ channels

2. their thresholds for excitation are too high.

52

what does capable theory take into account 

1. membrane capacitance

2. embrane resistance

3. longitudinal cytoplasmic resistance between different parts of the neuron

53

glutamate binding to ampa and nmda exhibits distinct

1. kinetics

2. pharmacologic sensitivites

3. target cell effects

54

interposition of a ____ in a neuronal circuit can prevent overactity in the cns

inhbiitior synapse

A image thumb