The Synapse

Front 1

the net charge within the cell is ?

Back 1

negative @ -70mV

Front 2

what ion has the highest relative conductivity?

Back 2

K+ potassium @ 1.00

Front 3

what ion has the lowest relative conductivity?

Back 3

Na+ @ 0.04

Front 4

what are the 2 forces that wish to cause an ion to move?

Back 4

electrical
concentration

Front 5

Sodium has a tendency to move _____ of the cell?

Back 5

into

Front 6

In terms in concentration K+ wishes to move _____ of cell and in terms of electrical it wishes to move _____ of cell

Back 6

out
into

Front 7

what is the membrane potential @ which K+/potassium is @ equilibrium?

Back 7

-94mV

Front 8

If concentration remains the same, and K+ mV rises from equilibrium to -70mV, what is the driving force and net result?

Back 8

Potassium seeks to move out of cell @ 24 mV because the electric pull is too weak to compete with the concentration gradient

Front 9

what is the driving force (mV) of sodium?

Back 9

140mV inward

Front 10

what is the driving force of chloride?

Back 10

45mV outward

Front 11

permeability x driving force =

Back 11

J: Flux

Front 12

Potassium (K+):
Permeability =
Driving force =

Back 12

High (permeability)
Low (driving force)

Front 13

Sodium (Na+):
Permeability =
Driving force =

Back 13

Low (permeability)
High (driving force)

Front 14

what determines the net flux of sodium and potassium in the cell and what is it?

Back 14

Sodium-Potassium pump transporters
3/2 : Na+/K+ therefore Na+ = 50% more

Front 15

the membrane potential of a cell will always resemble most closely to what?

Back 15

the most permeable ion

Front 16

the Goldman equation reveals that by the 3 most important ions, the resting membrane potential for a neuron = ?

Back 16

-65mV

Front 17

what is a poison to the 3/2 sodium potassium pump?

Back 17

ouabain

Front 18

the cell much reach what in order to depolarize?

Back 18

threshhold

Front 19

the peak of 'overshoot' during APs is @ what mV?

Back 19

+30 mV

Front 20

the period when the action potential is repolarizing below resting membran potential =

Back 20

absolute refractory period

Front 21

the period of time when the mV of the neuron is more negative than resting potential thus making ensuing APs less likely

Back 21

Relative Refractory Period

Front 22

what accounts for the predominance of sodium influx into the cell relative to potassium and the afterhyperpolarization period?

Back 22

Slow opening and closing K+ channels

Front 23

At rest:
Sodium inactivation gate:
Sodium activation gate:
Potassium gate:
Potassium channel (ungated):

Back 23

open
closed
closed
always open

Front 24

At Depolarization threshold:
Sodium inactivation gate:
Sodium activation gate:
Potassium gate:

Back 24

open
open
opening slowly

Front 25

During repolarization phase:
Sodium inactivation gate:
Sodium activation gate:
Potassium gate:

Back 25

closes
open
open ----> closing

Front 26

As the mV passes below threshold in a hyperpolarized state:
Sodium inactivation gate:
Sodium activation gate:
Potassium gate:

Back 26

closed
closed
open

Front 27

As the mV reaches normal resting potential again:
Sodium inactivation gate:
Sodium activation gate:
Potassium gate:

Back 27

open
closed
closing--->closed

Front 28

what type of APs move toward cell body?

Back 28

Antidromic Conduction

Front 29

what type of APs move away from cell body?

Back 29

Orthodromic Conduction

Front 30

What 2 features attribute to increased conduction velocity?

Back 30

- Increased diameter of axon
-myelination

Front 31

What are the cells that myelinate the PNS?

Back 31

Scwhann cells

Front 32

What are the cells that myelinate the CNS?

Back 32

Oligodendrocytes

Front 33

about every 1-2 mm there are breaks in myelination called _____?

Back 33

Nodes of Ranvier

Front 34

What is the jumping of APs along a myelinated axon referred to as?

Back 34

Saltatory Conduction

Front 35

The absolute refractory period prevents what in saltatory conduction and what in terms of action potential frequency?

Back 35

-prevents reverberating of axon in the opposite (antidromic) direction
-maximum discharge frequency @ about 400-500 impulses/sec

Front 36

The maximum discharge frequency in Absolute refractory period is a feature of what?

Back 36

inactivation gate being closed and eventually reopened for an AP to be possible

Front 37

Vesicles being loaded with neurotransmitters is a _______ processs

Back 37

ATP-dependent

Front 38

What is visualized at the presynaptic terminal suggesting high activity

Back 38

mitochondria

Front 39

What 2 proteins are important in holding vesicle at the presynaptic density and preventing exocytosis?

Back 39

Synapsin
Actin

Front 40

what is the link between the action potential and the exocytosis of neurotransmitters?

Back 40

Ca++ release within cell

Front 41

What type of voltage gated channels found in the presynaptic terminal are crucial for exocytosis of n.t.?

Back 41

N-type Ca++ channels

Front 42

what poison can irreversibly block N-type Ca++ channels in the Presynapse?

Back 42

w-conotoxin (shellfish)

Front 43

as a AP causes Ca++ influx, the intracellular conc. is increased and binds to _____ which subsequently INACTIVATES channels

Back 43

calcineurin

Front 44

Calcium fxns in releasing nt-vesicle by binding to ______ which activates the complex __________

Back 44

Calmodulin
Calmodulin-dependent protein kinase
(Cam-kinase II)

Front 45

Cam-kinase II fxns to do what?

Back 45

phosphorylate Synapsin I

Front 46

Phosphorylated Synapsin I fxns to do what?

Back 46

untether vesicles from actin thus enabling the vesicle to bind the presynaptic membrane for exocytosis

Front 47

what ion may pass thru Ca++ N-type channels resulting in an inhibtory effect on synaptic transmission

Back 47

Mg++

Front 48

what fxns to dock vesicles at membrane for exocytosis?

Back 48

Ca++

Front 49

What inactivates Synapsin I at the Presynaptic process?

Back 49

phosphatases

Front 50

Caclium is brought back to original concentration via?

Back 50

Calcium pump channels

Front 51

What accounts for pre-/post-synaptic alignment while no action potentials are being fired>

Back 51

release of quanta of neurotransmitters
as 'MEPPS'

Front 52

the process of vesicular recycling in presynaptic process?

Back 52

Inbudding by endocytosis

Front 53

If a vesicle just recycled has not yet been reloaded with neurotransmitters, what is would suggest this structurally?

Back 53

coated (clathrin)

Front 54

______ describes the diffusing of NT out of the cleft after release @ synapse

Back 54

washout

Front 55

where can washout occur?

Back 55

PNS

Front 56

what prevents washout from occuring within the CNS?

Back 56

glial cells that seal the synapse

Front 57

what would be the effector in a Gprotein gated receptor?

Back 57

Ionophore (ion channel)

Front 58

The neurotransmitter serves as the _____ in a gprotein gated receptor?

Back 58

ligand (ligand-gated receptors)

Front 59

Which are most selective:
ligand-gated vs. voltage-gated

Back 59

voltage-gated

Front 60

if channels permeable to Na+ and K+ experience an EPSP, the mV will be changed how?

Back 60

depolarize and average out @ about -20mV = -90 + 50

Front 61

PSPs that occur simultaneously in a consecutive manner prior to the former PSP decrementing

Back 61

Temporal Summation of PSPs

Front 62

In the case multiple PSPs are generated simultaneously at different locations on the post synaptic terminus

Back 62

Spatial Summation

Front 63

action potential usually propagate at which site of a neuron?

Back 63

axon hillock

Front 64

an action potential is most likely to develop at a site with the ____?

Back 64

lowest potential

Front 65

most EPSPs are found at what aspect of neuron?

Back 65

dendrites

Front 66

most IPSPs are found at what aspect of neuron?

Back 66

soma

Front 67

Parasympathetics of the ANS are deemed ______ based on its regions of innervation

Back 67

Craniosacral

Front 68

what is the ratio of preganglion:postganglionic for the Sympathetics?

Back 68

1:20
divergent effect

Front 69

what is the ration of preganglionic:postganglionic for the Parasympathetics?

Back 69

1:1
targeted

Front 70

what is the primary neurotransmitter for the parasympathetic postganglionic synapse?

Back 70

Ach

Front 71

what is the primary neurotransmitter for the sympathetic postganglionic synapse?

Back 71

NoreEpi

Front 72

the Splanchnic nerve innervates the ______ to release ______ and therefore is a _______ preganglionic sympathetic axon

Back 72

adrenal medulla
Epi/Nor

Front 73

what is the exception for sympathetics releasing primarily NE at postganglionic terminus?

Back 73

sweat glands and some blood vessels that have muscarinic receptors for Ach

Front 74

what are the main inhibitory NT in the CNS?

Back 74

GABA (gamma amino butyric acid)
ionotropic form

Front 75

what is the main inhibitory NT in the PNS?

Back 75

glycine

Front 76

Ach is synthesized by ______?

Back 76

Choline Acetyltransferase (ChAT)

Front 77

how does the presynaptic cell deal with the scarcity of choline?

Back 77

50% recycled via sodium driven reuptakes channels

Front 78

Ach depletion results due to _____ targeting the ChAT converting enzyme which decreased Ach synthesis

Back 78

Napthylvinal pyridine

Front 79

causes the releasing of vesicles depleting the number for further use at synapse

Back 79

Beta-bungarotoxin
BWSV (black widow spider venom)

Front 80

toxin resulting in few Ach vesicles being released

Back 80

botulinum toxin

Front 81

what toxin act on the reuptake transporter for choline on the presynaptic process causing Ach depletion

Back 81

hemicholinium

Front 82

what acts on AchR reversibly prolonging Ach transmission

Back 82

neostigmine
physostigmine

Front 83

what acts on AchR irreversibly prolongin Ach transmission

Back 83

malathion

Front 84

Ach
Nicotine
Carbachol

Back 84

nicotinic agonists

Front 85

Muscarine
Pilocarpine
Oxotremorine

Back 85

muscarinic agonists

Front 86

Curare
Succinyl Choline
Rabies virus

Back 86

nicotinic antagonists

Front 87

Atropine
Scopolamine

Back 87

muscarinic antagonists

Front 88

what is the typical effector for nicotinic receptors?

Back 88

Na+/K+ channels

Front 89

what are the typical effetor for muscarinic receptors?

Back 89

G-protein coupled mechanism
- inhibit adenyl cyclase
- stimulate guanylate cyclase
-stimulate phosholipase C
- alter ion channels (via cAMP)

Front 90

DA, NE, EPi are all ?

Back 90

catecholamines and thus derived from L-tyrosine

Front 91

what converts L-DOPA to Dopamine?

Back 91

DOPA Decarboxylase

Front 92

what converts Dopamine to NE?

Back 92

Dopamine -Beta- Hydroxylase

Front 93

what converts NE to Epi?

Back 93

Phenylethanolamine-N-methyl transferase

Front 94

will displace catecholamine NT from vesicles causing an initial release which further depletes NT release in the future?

Back 94

amphetamines
gamma-hydroxyl-butyrate for DA

Front 95

enhances EPi release from adrenal medulla?

Back 95

cortisol

Front 96

acts on the reuptake channels for NE and thus initially leaves it in channels longer, w/ long term depletion

Back 96

cocaine

Front 97

depletes NE into vesicles and thus has long lasting depletion of NE release

Back 97

Reserpine

Front 98

what %of NE is reuptaken into the presynaptic process?

Back 98

80%

Front 99

what is the end product of NE/EPi catabolism?

Back 99

VMA Vanillylmandelic acid

Front 100

what is the end product of DA catabolism?

Back 100

HVA Homovanillic acid

Front 101

what are the two enxymes involved in catecholamine catabolism?

Back 101

MAO - monoamine oxidase
COMT - Catechol-O-Methyl Transferase

Front 102

how doe the body rid of HVA and VMA?

Back 102

urine excretion

Front 103

what catabolic enzyme for catecholamines is found on the mitochondrial membrane?

Back 103

MAO

Front 104

MAO inhibitors would tend to ______ storage of NT in terminals in regards to vesicle formation

Back 104

increase

Front 105

tropoline is a ?

Back 105

COMT inhibitor

Front 106

pargyline is a?

Back 106

MAOI

Front 107

where is the source of most of the adrenergic neurons in the CNS?

Back 107

Locus Ceruleus

Front 108

where is the source of most of the dopaminergic neurons in the CNS?

Back 108

Substantia Nigra

Front 109

_____% of dopaminergic neurons travel to the Corupus striatum via the ______ tract

Back 109

80%
Niagrostriatal tract

Front 110

_____ is an analog of the drug Meperdine and will cause degeneration of the Niagrostriatal tract

Back 110

MPTP

Front 111

What are the Dopamine receptor subtypes that utilize Adenyl cyclase to increase cAMP?

Back 111

D1/D5

Front 112

Ephedrin
Methoxamine
Clonidine

Back 112

adrenergic alpha receptor agonists

Front 113

Phenoxybensamine
Phentolamine
Yohimbine

Back 113

adrenergic alpha receptor antagonists
Phenoxybensamine - both
Phentolamine - alpha 1
Yohimbine - alpha 2

Front 114

Isoproterenol
Dobutamine
Albuterol

Back 114

adrenergic beta receptor agonists
Isoproterenol - both
Dobutamine - beta 1
Albuterol - beta 2

Front 115

Propranolol
Atenolol

Back 115

adrenergic beta receptor antagonists

Front 116

alpha 2 adrenergic receptors have what sort of activity on the postsynaptic process?

Back 116

inhibitory effect