Synapse II

Question 1

What is the major excitatory neurotransmitter of the brain?

Answer 1

GlutaMATE

Question 2

What is the major inhibitory neurotransmitter of the brain?

Answer 2

GABA

Question 3

Most projection neurons such as long axons and linking brain areas release what as a neurotransmitter?

Answer 3

GlutaMATE

Question 4

Most interneurons such as short axons, local circuit, axons within the brain area, release what as a neurotransmitter?

Answer 4

GABA

Question 5

Both GlutaMATE and GABA are synthesized from ____ by enzymes within the _______

Answer 5

amino acids; axon terminal

Question 6

Both GlutaMATE and GABA are actively transported into _______

Answer 6

synaptic vesicles

Question 7

Both GlutaMATE and GABA activate ____ and ____ receptors that are selective for each transmitter

Answer 7

ionotropic; metabotropic

Question 8

After release, both GlutaMATE and GABA are actively transported ____ of the synaptic cleft to terminate the action

Answer 8

out

Question 9

Pyramidal neurons make up ___% of cortical neurons while Interneurons make up ___% of cortical neurons.

Answer 9

80%; 20%

Question 10

Pyramidal neurons use which neurotransmitter?

Answer 10

glutaMATE

Question 11

Interneurons use which neurotransmitter?

Answer 11

GABA

Question 12

Specific transporters pump glutaMATE and GABA into ______. After release, specific transporters then pump them out of the synaptic cleft in order to ____ the action.

Answer 12

vesicles; terminate

Question 13

Where are GlutaMATE and GABA also transported into?

Answer 13

Glia

Question 14

Glia are converted to ____ which is then transported back into the neurons and converted back into what?

Answer 14

glutaMINE; glutaMATE

Question 15

GABA is synthesized from glutaMATE in one extra step by which enzyme?

Answer 15

GAD (glutamic acid decarboxylase)

Question 16

What are the 2 main subtypes of ionotropic glutaMATE receptors?

Answer 16

AMPA and NMDA

Question 17

Both AMPA and NMDA are present at the same ______ synapses and are nonselective ____ channels

Answer 17

glutamatergic; cation

Question 18

AMPA receptor:

1. Bind of glutaMATE ____ the channel
2. Na+ flows ___ the postsynaptic neuron (down electrochemical gradient)
3. K+ flows ___ and has a ____ drive on ion; ___ current
4. Postsynaptic neuron __-polarizes
5. _PSP

Answer 18

1. opens
2. into
3. in; weaker; less
4. depolarizes
5. EPSP

Question 19

NMDA receptor:

1. Ion channel pore of NMDA receptors is ____ by ____ ions at rest
2. If the __-synaptic neuron fires, and the ___-synaptic neuron is at resting membrane potential, glutaMATE opens NMDAR but __ current flows thru channel
3. If the __-synaptic neuron is depolarized, and the ___-synaptic neuron fires, NMDAR opens and __ ions are expelled from the pore
4. __ ions flow through NMDAR into the __-synaptic neuron
5. Calcium activates enzymes that lead to insertion of more ____ receptors in synapse
6. Synapse becomes ____, which causes a larger _PSP associated with synaptic plasticity/learning

Answer 19

1. blocked; Mg2+
2. pre-; post-; NO
3. post-; pre-; Mg2+
4. calcium; post-
5. AMPA
6. Stronger

Question 20

What is excitotoxicity? What is its clinical application?

Answer 20

Pathologically high neurotransmitter levels which leads to excess stimulation of receptors

Stroke

Question 21

During stroke, what rises (extracellular) rapidly due to hypoxia-ischemia (blocked blood flow to cells/organs)?

Answer 21

glutaMATE

Question 22

Over-activation of what results in excessive influx of calcium ions to a level that activates enzymes to trigger cell death?

Answer 22

NMDAR

Question 23

Blocking NMDAR lessens neuronal death in ___ stroke, but not ____ potentially due to incorrect dosage or insufficient early timing post-stroke

Answer 23

animal; human

Question 24

NMDAR antagonists mimic the clinical symptoms of which mental disorder?

Answer 24

Schizophrenia

Question 25

In Schizophrenia, it's been recently studied that there seems to be a link with the disorder and mutations involving genes that play a role in ____ synaptic function

Answer 25

NMDAR

Question 26

MGluRs are considered to be ____tropic receptors

Answer 26

metatropic

Question 27

MGluRs have many ____

Answer 27

subtypes

Question 28

MGluRs are located at synapses on dendrites, cell bodies and on __synaptic terminals

Answer 28

pre

Question 29

MGluRs modulate the activity of ion channels and other proteins influencing the electrical ____ of neurons

Answer 29

excitability

Question 30

MGluRs can exert excitatory OR inhibitory effects on ___synaptic neurons

Answer 30

post

Question 31

GABA is considered to be a ____tropic receptor

Answer 31

ionotropic

Question 32

With GABA, there is a high concentration of ___ outside the neuron and a ___ mV charge inside to counteract it

Answer 32

Cl- ; -70

Question 33

Binding of GABA to GABA-A receptor ___ Cl- selective ion channels

Answer 33

opens

Question 34

Equilibrium potential for Cl- is ___mV. Resting membrane potential is close to that at about ___mV, which means the drive on Cl- is ___ at resting potential.

Answer 34

-70; -65; weak

Question 35

If Cl- channels are OPEN, and other excitatory synapses start to DEPOLARIZE the neuron, Cl- ions will do what? What is this called?

Answer 35

Move into the neuron and hold its membrane near -70mV Shunting inhibition which prevents the neuron from being excited

Question 36

GABA-B is considered to be a ___tropic receptor

Answer 36

metatropic

Question 37

GABA-B ___neuronal excitability because it ___ the K+ channels

Answer 37

inhibits; opens

Question 38

GABA-B ___ neurotransmitter release by closing the voltage-gated ___ channels

Answer 38

inhibits; calcium

Question 39

Seizures reflect insufficient inhibition of what?

Answer 39

GABAergic local circuits

Question 40

Excessive synchronization of cortical neurons results when there is not a sufficient amount of _____ / loss of ____/ increased _____ levels, which can cause seizures

Answer 40

GABA-A binding; GABA neurons; glutaMATE

Question 41

Prolonged, untreated seizure activity leads to additional damage to ____ networks (excitotoxicity)

Answer 41

cortical

Question 42

Anxiety disorder and panic disorder is associate with reduction in which receptor binding?

Answer 42

GABA-A (and general reduced GABA levels)

Question 43

GABA drugs are most commonly used for purposes such as anti-___, ___-lytic, and adjunctive use for situations involving ______

Answer 43

1. Anti-seizure 2. Anxiolytic 3. Anesthesia

Question 44

Normal release of GABA is required in _____ receptor positive allosteric modulators, as they enhance already existing GABA and its actions

Answer 44

GABA-A

Question 45

Barbiturates such as phenobarbital, pentobarbital and thiopental ___ the duration of Cl-ion channel opening of ____ receptors in response to GABA.

Answer 45

increase; GABA-A

Question 46

What are the risks of Barbiturates?

Answer 46

Severe risk of respiratory, cardiovascular and CNS depression. Severe risk of dependence.

Question 47

Benzodiazepines such as diazepam (valium), lorazepam and midazolam ____ the frequency of Cl-ion channel opening of ____ receptors in response to GABA.

Answer 47

increase; GABA-A

Question 48

Nearly all neurons receive both _____ and ____ synaptic input

Answer 48

excitatory; inhibitory

Question 49

EPSPs and IPSPs sum in the dendritic tree and cell body to determine whether the ___synaptic neuron will fire an action potential

Answer 49

post

Question 50

The action of an EPSP or IPSP depends on the _____ it binds to and activates

Answer 50

receptor