Unit 8

Question 1

what is a neuropeptide transmitter

Answer 1

a type of neurotransmitter made of a small chain of amino acids (a peptide) that is synthesized in the neuron’s cell body, packaged into vesicles, and released to act as a chemical messenger in the nervous system

• modulate slow, long-lasting signaling
• act through metabotropic receptors
• influence mood, pain, stress, reward, and homeostasis

Question 2

synthesis of glutamate

Answer 2

Glutamine is converted by enzyme glutaminase and forms glutamate

Question 3

release of glutamate

Answer 3

Glutamate synthesis–> moved into Vesicles with VGLUT 1/2/3 –> action potential–. release glutamate though excytosis into cleft –> Glutamate binds to receptors

Question 4

inactivation of glutamate

Answer 4

mostly removed not broken down (reuptake and recycled)

Glutamate released
↓
Reuptake
into Astrocyte (EAAT2)
–> Glutamate converted by Glutamine Synthetase → Glutamine released
↓
Glutamine converted to Glutamate with enzyme: Glutaminase
↓
Glutamate repackaged into vesicles via VGLUT1/2/3
↓
Stored and Ready for next release

Question 5

organization of glutamatergic system

Answer 5

Cortex → pyramidal neurons (main output system)

Hippocampus → learning pathways (Schaffer collateral, etc.)

Cerebellum → parallel fibers
→ Glutamate pathways = widespread, not localized.

Question 6

function of glutamatergic system

Answer 6

Fast excitation

Learning & memory

Synaptic plasticity

Motor activity

Linked to disorders (schizophrenia, addiction, ALS, stroke

Question 7

synthesis of GABA

Answer 7

GAD converts glutamate to GABA

Question 8

inactivation of GABA

Answer 8

Reuptake via GAT 1,2,3 ending inhibitors signal

Enzyme break down
GABA-T -> Glutamate -> succinate

Question 9

organization of GABAergic system

Answer 9

GABA is the major inhibitory neurotransmitter in the brain and is widely distributed. GABAergic neurons are found in:
the cerebral cortex
hippocampus
substantia nigra
cerebellum
striatum
globus pallidus
olfactory bulb.
Using both local interneurons and long-range projection neurons to regulate excitability across motor, cognitive, and sensory circuits.

Question 10

Function of GABAergic system

Answer 10

1. Primary function: inhibition and balance
   hyperpolarize target cells, reducing the likelihood of action potentials.
   Provides “brakes”
2. Circuit-level roles
   - cortex & hippocampus: regulates cell firing
   - basal ganglia: control motor output
   - cerebellum: fine movement, balance, and coordination
3. Clinical importance
   - Reduced GABA function → seizures/epilepsy, anxiety, increased excitability.

Question 11

What is glutamate

Answer 11

the ionized (electrically charged) form of the amino acid glutamic acid and the most abundant amino acid in the brain. Members of small family of excitatory amino acid neurotransmitters that cause a powerful excitatory response when applied to most neurons in the brain or spinal cord. Used by all of our cells to help make new proteins.

Question 12

what is GABA

Answer 12

Main inhibitory neurotransmitter in the brain.
(Glutamate = Go, GABA = Stop.)

Question 13

functions of metabotropic glutamate receptors

Answer 13

8 metabotropic glutamate receptors (mGluR1–mGluR8). modulate neural activity rather than mediating fast transmission: Group I increases postsynaptic excitability, while Groups II and III inhibit presynaptic neurotransmitter release and regulate excitability, plasticity, mood, pain, and neuroprotection.

Question 14

what is the role of glutamate receptors in long-term potentiation?

Answer 14

Glutamate receptors initiate and strengthen long-term potentiation by using AMPA receptors to depolarize the postsynaptic cell and NMDA receptors to allow Ca²⁺ entry once depolarization occurs. This Ca²⁺ signal triggers the synaptic strengthening that defines LTP.

Question 15

what is the structure of GABAa receptor

Answer 15

ionotropic receptor
two α subunits, two β subunits, and one γ subunit.
Imultiple allosteric binding sites for drugs such as benzodiazepines, barbiturates, ethanol, and neurosteroids.

Question 16

anxiolytic drugs

Answer 16

are drugs that reduce anxiety—mainly by enhancing GABA’s inhibitory actions, especially through GABAA receptors (e.g., benzodiazepines).

Question 17

how do anxiolytic drugs work

Answer 17

Anxiolytic drugs work by enhancing GABA-mediated inhibition—usually by helping GABAA receptors open more effectively—thereby calming neural activity and reducing anxiety.
1. They bind to an allosteric site on the GABAA receptor.
2. They increase GABA’s effect on the receptor.

inhibition of overactive brain circuits involved in anxiety

Question 18

what is the structure of GABAb receptor

Answer 18

metabotropic G-protein–coupled two subunits, B1 and B2,
receptors are found both presynaptically and postsynaptically.

Question 19

Which cell type plays a major role in clearing glutamate from the synapse

Answer 19

Astrocyte

Question 20

what is responsible for packaging glutamate into vesicles

Answer 20

VGLUT1, VGLUT2, and VGLUT3

Question 21

What enzyme converts glutamine → glutamate?

Answer 21

Glutaminase.

Question 22

What proteins load glutamate into vesicles?

Answer 22

VGLUT1, VGLUT2, VGLUT3.

Question 23

What transporter handles 90% of glutamate uptake?

Answer 23

EAAT2 (on astrocytes).

Question 24

What enzyme converts glutamate → glutamine inside astrocytes?

Answer 24

Glutamine synthetase.

Question 25

What happens when EAAT2 is knocked out?

Answer 25

Seizures, excitotoxicity, early death.

Question 26

What precursor do neurons use to make glutamate?

Answer 26

Glutamine (converted inside neurons into glutamate)

Question 27

Which VGLUT transporter is responsible for vesicle loading and where

Answer 27

VGLUT1 → cortex & hippocampus VGLUT2 --> subcortical structures VGLUT3 --> special cases

Question 28

What transporter removes glutamate from the synapse

Answer 28

EAAT2 (astrocytes; accounts for ~90% of glutamate clearance)

Question 29

What happens to glutamate once it enters an astrocyte?

Answer 29

It is converted into glutamine by the enzyme glutamine synthetase, then released back to neurons.

Question 30

What are the ionotropic receptors for glutamate?

Answer 30

AMPA: GluA1–4 NMDA: GluN1 + GluN2 (A–D), ± GluN3 Kainate: GluK1–5

Question 31

Which glutamatergic receptors are primarily responsible for LTP?

Answer 31

NMDA AMPA

Question 32

Major pathways that use glutamate

Answer 32

Cerebral cortex Cerebellum Hippocampus

Question 33

2 families of Glutamate receptors

Answer 33

ionotropic (fast) metabotropic (slow)

Question 34

metabotropic glutamate receptors

Answer 34

mGLUR 1-8

Question 35

functions of ionotropic glutamate receptors

Answer 35

fast-acting, ligand-gated ion channels that mediate rapid excitatory neurotransmission in the CNS. contribute to key processes like learning, memory, synaptic plasticity, and regulation of neuronal excitability

Question 36

what is long-term potentiation?

Answer 36

a long-lasting increase in synaptic strength

Question 37

Why is LTP relevant?

Answer 37

shows how repeated activity strengthens synapses. It explains how learning and memory occur at the synaptic level. It shows how synapses become stronger through activity-dependent changes, which is the biological basis for forming long-lasting memories.

Question 38

Excitotoxicity

Answer 38

Too much glutamate → too much Ca²⁺ → neuron damage or death. Seen in: stroke trauma Alzheimer’s ALS

Question 39

Which substances modulate the effects of GABA via its receptors?

Answer 39

Neurosteroids and anesthetics Barbiturates and benzodiazepines Ethanol (alcohol)

Question 40

Inactivation of GABA

Answer 40

GABA is inactivated by reuptake via GAT transporters and by enzymatic breakdown via GABA-T. Some of the breakdown products enter a recycling cycle involving glutamine and glutamate, but this is not part of inactivation itself. 1)reuptake 2) enzyme breakdown

Question 41

function of GABAa receptor

Answer 41

When GABA binds, the channel opens and Cl⁻ ions flow into the neuron, causing hyperpolarization. This produces fast inhibitory neurotransmission, reducing the likelihood of an action potential. Extrasynaptic GABAA receptors generate tonic inhibition, while synaptic receptors produce phasic inhibition.

Question 42

function of GABAb receptor

Answer 42

Postsynaptically, GABAB activation opens K⁺ channels, producing slow hyperpolarization and decreased neuron excitability. Presynaptically, GABAB receptors inhibit Ca²⁺ channels, reducing neurotransmitter release (acting as autoreceptors or heteroreceptors). They also reduce cAMP formation, contributing to long-lasting inhibitory effects.

Question 43

what is GABAa receptor

Answer 43

A fast, ionotropic Cl⁻ channel producing quick inhibition and targeted by benzodiazepines and alcohol.

Question 44

What is GABAb receptor

Answer 44

A slow, metabotropic GPCR that inhibits neurons by opening K⁺ channels and blocking Ca²⁺-dependent neurotransmitter release.

Question 45

NTs and what do they do?

Answer 45

NE → Glu → DA → 5HT → ACh → GABA Wake up and GO get your REWARD to boost your MOOD, then REMEMBER to CHILL and finally STOP!