Neurobiology: Exam 3 (Synaptic Transmission, Integration, Neurotransmitters, Etc...)

Front 1

___________ introduced the term cholinergic to describe cells that produce ACh, and termed the neurons that use the amine neurotransmitter NE as noradrenergic.

Back 1

Henry Dale

Front 2

_____________ showed definitively that sympathetic transmission between nerve and heart is chemically mediated. First molecule identified as a neurotransmitter, ACh. Provided support of chemical synapses.

Back 2

Otto Loewi

Front 3

______________ signaling molecules in the cardiovascular system (nitric oxide). He discovered EDRF (endothelium-derived relaxing factor), a substance in endothelial cells that relaxes blood vessels.

Back 3

Fuchgott

Front 4

______________ and ________________ demonstrated that fast transmission at the synapse between a motor neuron axon and a skeletal muscle was chemically mediated.

Back 4

Katz and Brindley

Front 5

The presynaptic neuron and the postsynaptic neuron are are associated with _____________ messages, whereas the synaptic space (cleft) is associated with _______________ messages.

Back 5

Electrical, Chemical

Front 6

In a synapse, information flows from ______________ to _________________.

Back 6

Presynaptic Neuron to a Postsynaptic Neuron (target cell)

Front 7

The 2 types of Synapses are Electrical and Chemical. What are some characteristics of an electrical synapse?

Back 7

Electrical Synapse

- Bidirectional

- Direct Transfer of ionic current flow

- occurs at Gap Junctions

- Common in the CNS

- High speed transmissions.

- Common in early embryonic growth/developm.

- Synchronizes neurons for symp. integr. & PSP

Front 8

A ___________________ allows for the flow of ions and small organic molecules between the cytoplasms of two or more neurons.

Back 8

Gap Junction

Front 9

What are the contents of a Gap Junction:

Back 9

Gap Junction Contents:

- many Gap Junction channels

- 2 Connexons

- 2 Connexins

Front 10

_____________________ is where each neuron synapses electrically which multiple neighboring neurons which increases the PSP of that neuron to reach threshold and fire an action potential.

Back 10

Synaptic Integration

Front 11

The 2 types of Synapses are Electrical and Chemical. What are some of the characteristics of a Chemical Synapse?

Back 11

Chemical Synapse

- Uni-directional

- Most Common transmission of the Nervous System

- Synaptic Cleft

- Synaptic Vesicles

- Active Zone

- Postsynaptic Density

Front 12

The ____________ ___________ separates the presynaptic and the postsynaptic membranes at chemical synapses.

- Large Width

- Filled with an extracellular matrix that functions to make the pre- and post- synaptic membranes adhere to one another.

Back 12

Synaptic Cleft

Front 13

______________ ___________ are small membrane-enclosed spheres, dozens of which are located on the presynaptic side of the synapse (the axon terminal).

- Function: store neurotransmitters for communication with the postsynaptic neuron.

Back 13

Synaptic Vesicles

Front 14

__________ _____________ are larger vesicles of the axon terminal. They contain soluble proteins that appear dark in electron microscopes (aka "Dense Core Vesicles").

- Membrane Differentiation

- Dense accumulation of protein adjacent to and within the membranes on either side of the synaptic cleft.

Back 14

Secretory Granules

Front 15

The _________ ________ is the site of neurotransmitter release. It is composed of the membrane and protein on the presynaptic cell that penetrate the intracellular face of the cytoplasm of the terminal.

- Location: Adjacent to clustered synaptic vesicles.

Back 15

Active Zone

Front 16

___________ ____________ protein thickly accumulated underneath the postsynaptic membrane.

- Contains: neurotransmitter receptors that convert the intracellular chemical signal into an intracellular signal in the postsynaptic cell.

Back 16

Postsynaptic Density

Front 17

What are the two types of chemical synapses?

Back 17

CNS Synapse

and

Neuromuscular Junction

Front 18

_________________ is where different types of synapses are determined by which part of the neuron is postsynaptic to the axon terminal.

Back 18

CNS Synapse

Front 19

Name the term for each type of CNS Synapse:

a) axon to dendrite = _________________

b) axon to cell body = ________________

c) axon to axon = __________________
d) dendrite to dendrite = _________________

Back 19

a) Axodendric

b) Axosomatic

c) Axoaxonic

d) Dendrodendric

Front 20

A ______________________ exists outside the CNS, and is a chemical synapse between axons of motor neurons of the spinal cord and skeletal muscles.

- Fast and Reliable.

- Largest synapse in the body with large number of active zones in the presynaptic terminal.

Back 20

Neuromuscular Junction

Front 21

In the Neuromuscular Junction, 1 AP (presynaptic) = __ AP (postsynaptic). This is caused by the release of 200 synaptic vesicles.

*the rest of the nervous system is not "1 for 1" because the postsynaptic potential (PSP) is too small*

Back 21

1 AP

Front 22

What are the steps in neurotransmitter synthesis?

Back 22

- Peptide (peptide synthesized in rough ER, peptide split in the Golgi Apparatus, secretory vesicles contain peptide bud, & secretory granules transported down axon to terminal)

- Amine & amino acid Neurotransmitter (Enzymes convert persecutor molecules into neurotransmitter molecules, transporter proteins load the neurotransmitters into synaptic vesicles)

Front 23

What are the steps in the release of neurotransmitters?

Back 23

- Release triggered by an Action Potential in the axon terminal.

- Influx of Ca2+ through voltage-gated calcium channels

- Synaptic vesicle (containing neurotransmitters) releases them in the synaptic cleft by fusion of the vesicle membrane with the presynaptic membrane. Then, its recycled by endocytosis

Front 24

What are the steps in neurotransmitter recovery and degradation?

Back 24

- *Neurotransmitter interacts with the Postsynaptic receptors.* And in return, it is cleared from the synaptic cleft to allow another transmission.

- Simple Diffusion of the transmitter molecules away from the synapse (aided by the uptake into the presynaptic axon terminal).

Front 25

What are the other sequence of events of a Synaptic Transmission:

1. Presynaptic Action Potential

2. Depolarization of Synaptic Terminal

3. ...

#3 - #6 = ____?

Back 25

3. Release of chemical neurotransmitter molecules

4. Neurotransmitter molecules bind to special receptors on postsynaptic cells

5. Change in ionic permeability of postsynaptic cell

6. Change in membrane potential of postsynaptic cell

Front 26

Which neurotoxin leaves the following effect(s)?

- cleave sore SNARE complex

- no vesicle fusion

Back 26

Botulinum Toxin

Front 27

Which neurotoxin leaves the following effect(s)?

- blocks AChE channel in closed position

- paralysis

Back 27

Bungarro Toxin

Front 28

Which neurotoxin leaves the following effect(s)?

- AChE inhibitor

- Muscle depolarization

- Paralysis of diaphragm muscle

- Stop breathing

Back 28

Sarin

Front 29

Which neurotoxin leaves the following effect(s)?

- Blocks AChR channels from opening

- Paralysis

Back 29

Curare

Front 30

The active zone is on the __________________ terminal and is where synaptic vesicles fuse with the _________________ plasma membrane.

Back 30

Presynaptic

Front 31

The _______________ density is part of the ______________ terminal, containing NT receptors.

Back 31

Postsynaptic

Front 32

A Synaptic Transmission involves the release of a neurotransmitter by a neuron at the Presynaptic terminal involves depolarization of the ________________.

Back 32

Axon Terminal

Front 33

A Synaptic Transmission involves the release of a neurotransmitter by a neuron at the Postsynaptic membrane involves depolarization of the ______________________.

Back 33

Membrane

Front 34

The _________________ effects include:

- Synaptotagmin serves as the Ca2+ sensor

- NSF hydrolyzes ATP to power the process.

On the Neuron Membrane: (contents)

- Syntaxin - SNAP-25 on vesicle

- Synaptobrevin - Synaptotagmin

Back 34

SNARE Complex

Front 35

Which of the following neurotoxins leaves the following effect(s)?

- causes calcium-independet exocytosis of all the synaptic vesicles

- paralysis (because the presynaptic terminals would not have any NT ready to be released &the receptors might remain stimulated indefinitely)

Back 35

Latrotoxin (Black Widow Toxin)

Front 36

_________________ functions as a neuromodulator. In the PNS, it activates muscles (triggers AP). In the CNS, it promotes REM sleep and associated with perception when we wake up.

Back 36

Acetylcholine

Front 37

__________________, in the brain, functions as neurotransmitter. Reward-motivated behavior and addictive drugs increase the neuronal activity of this neurotransmitter.

Back 37

Dopamine

Front 38

__________________ functions as a neurotransmitter, and is stored in vesicles at chemical synapses. AP trigger the release of it from the presynaptic cell.

- It also functions in parts of learning and memory.

Back 38

Glutamine

Front 39

_________ is produced when a neurotransmitter is released from presynaptic terminal, and binds to ion channels in postsynaptic membrane.

- Na+ enters open channels, causing depolarization, and a more positive membrane potential.

*caused by change in Vm*

Back 39

Excitatory Post-Synaptic Potential (EPSP)

- increased likelihood of PSP occurring

Front 40

__________ relates to transient hyper polarization of the postsynaptic membrane potential caused by the presynaptic release of neurotransmitter.

- *caused by Glycine-gated or GABA-gated ion channels*

Back 40

Inhibitory Post-Synaptic Potential (IPSP)

- decreased likelihood of PSP occurring

Front 41

____________ can be produced by opening Na+ or Ca2+ channels and an __________ can be produced by opening of Cl- or K+ channels.

Back 41

EPSP's, IPSP's

Front 42

____________________ => the summation of all IPSP and EPSP will determine if threshold is met and if AP will be generated.

Back 42

Neuronal Integration

Front 43

____________________ is the adding together of EPSP's generated at the same synapse if they occur in rapid succession, within about 1-15 msec of one another.

Back 43

Temporal Summation

Front 44

____________________ is the adding together of EPSP's generated simultaneously at many different synapses on a dendrite.

Back 44

Spatial Summation

Front 45

____________________, a type of synaptic inhibition, that reduces membrane resistance, thereby shunting depolarizing current generated at excitatory synapses.

Back 45

Shunting Inhibition

Front 46

_________________ is the amount of time that a PSP will last at a given membrane location, defined as tau (tau = membrane resistance x membrane capacitance). Time it tales for constant applied voltage to build up to 63% of its final value.

Back 46

Time Constant

Front 47

_____________________ is the distance that a PSP can spread along the membrane, defined as lambda (lambda = resistance of membrane / resistance of cytoplasm).

Back 47

Length Constant

Front 48

There are no voltage-gated sodium channels in dendrites.

True/False?

Back 48

True

Front 49

Which receptors are involved with the neurotransmitter Glutamate, in Long Term Potential?

Back 49

AMPA & NMDA

- Na+ comes in through the AMPA receptor

- GLU interacts with the AMPA

- Na+ triggers Mg+ to go out the NMDA channel

- Calcium flows in through the NMDA

- Ca2+ goes to secondary messengers

- stimulates paracrine from the postsynaptic

- stimulates release of more glutamate

Front 50

A _________________ neurotransmitter receptor use NT gated ion channel that drive ionic conductance upon binding of its specific receptor.

Ex:

- nicotinic receptor

- AMPA & NMDA receptor

- GABA A & C

Back 50

Ionotropic

Front 51

A ______________________ neurotransmitter relates with (GPCR) G-Protein coupled receptors that use G-Protein to start indirect, widespread, intracellular cascade using secondary messengers.

Ex:

- Muscaranic -Adrenergic Alpha alpha1,2 beta1,2

- GABA B

Back 51

Metabotropic

Front 52

What are the the neurotransmitters (in order) involved in the synthesis of catecholamines from Tyrosine?

Back 52

(Tim-Digs-Down-Neuro-Eggs)

Tyrosine

Dopa

Dopamine

NE (norepinephrine)

Epinephrine