Synapse, NT

Question 1

What are the two classes of neurotransmitter receptors?

Answer 1

Fast ionotropic receptors and slow metabotropic receptors[1]

Question 2

What is the role of calcium in synaptic transmission?

Answer 2

Calcium influx stimulates vesicles to fuse with the membrane and release neurotransmitter into the synaptic cleft (exocytosis)[1]

Question 3

What are SNARE proteins and their function?

Answer 3

SNARE proteins mediate fusion of synaptic vesicles with the presynaptic membrane. They include v-SNARE (synaptobrevin) and t-SNAREs (syntaxin and SNAP25)[1]

Question 4

What is the function of synaptotagmin?

Answer 4

Synaptotagmin acts as a calcium sensor and fusion clamp in synaptic vesicle exocytosis[1]

Question 5

List the primary excitatory and inhibitory neurotransmitters in the CNS

Answer 5

Excitatory: Glutamate; Inhibitory: GABA (brain) and Glycine (spinal cord)[1]

Question 6

What are the two ways neurotransmitter effects are terminated?

Answer 6

1. Removal from synaptic cleft by reuptake or glial cell transporters, 2. Extracellular destruction (e.g., diffusion)[1]

Question 7

What are the three main groups of metabotropic glutamate receptors?

Answer 7

Group I (mGlu1

Question 8

What is the primary function of ionotropic receptors?

Answer 8

Ionotropic receptors are coupled to ion channels and control ion flux across the cell membrane for rapid signaling in nerve and muscle[1]

Question 9

What is the typical width of the synaptic cleft?

Answer 9

20-40 nm[1]

Question 10

What is a quantum in neurotransmitter release?

Answer 10

A quantum represents the release of the contents of one synaptic vesicle[1]

Question 11

What is a miniature post-synaptic current (mPSC)?

Answer 11

A small postsynaptic signal produced by the release of a single synaptic vesicle[1]

Question 12

What is the typical delay for synaptic transmission?

Answer 12

Approximately 1 millisecond[1]

Question 13

What type of calcium channels regulate synaptic release in most CNS neurons?

Answer 13

P/Q (CaV2.1) or N (CaV2.2) calcium channels[1]

Question 14

What is Lambert-Eaton myasthenic syndrome?

Answer 14

An autoimmune disorder targeting P/Q channels in motor nerve terminals

Question 15

What is ziconotide and its use?

Answer 15

Ziconotide is a selective blocker of N-type calcium channels derived from marine snail toxins

Question 16

How many proteins are estimated to be in presynaptic terminals?

Answer 16

More than 1000 proteins[1]

Question 17

How many proteins are typically found on a single synaptic vesicle?

Answer 17

More than 80 proteins[1]

Question 18

What is the typical concentration of glutamate in a synaptic vesicle?

Answer 18

Approximately 100 mM[1]

Question 19

How do vesicles concentrate neurotransmitters?

Answer 19

Through active transport using a proton pump and vesicular neurotransmitter transporter[1]

Question 20

What is the difference in vesicular uptake between anionic and cationic neurotransmitters?

Answer 20

Anionic transmitters (e.g., glutamate) use vesicular membrane potential, while cationic transmitters (e.g., serotonin) are exchanged for protons[1]

Question 21

What protein helps assemble the SNARE complex?

Answer 21

Munc18-1[1]

Question 22

What is the function of complexin in synaptic vesicle fusion?

Answer 22

Complexin helps synaptotagmin clamp the SNARE complex to prevent spontaneous fusion[1]

Question 23

What is acetylcholine’s role in the nervous system?

Answer 23

Acetylcholine is the excitatory neurotransmitter at neuromuscular junctions, used by motor neurons, and in various parts of the CNS[1]

Question 24

How is acetylcholine synthesized?

Answer 24

Acetylcholine is synthesized in one reaction catalyzed by choline acetyltransferase

Question 25

What are the symptoms of organophosphate poisoning related to muscarinic receptor overstimulation?

Answer 25

Salivation

Question 26

How is glutamate recycled in the brain?

Answer 26

After release, glutamate is taken up by neurons and glia, converted to glutamine in astrocytes, then transferred back to neurons and reconverted to glutamate[1]

Question 27

What is the primary function of GABA in the CNS?

Answer 27

GABA is the primary inhibitory neurotransmitter in the CNS[1]

Question 28

How does glycine function in the nervous system?

Answer 28

Glycine is an inhibitory neurotransmitter, particularly in inhibitory interneurons of the spinal cord, but also acts as a co-agonist with glutamate for NMDA receptors[1]

Question 29

What are the four major dopamine tracts in the CNS?

Answer 29

1. Mesolimbic-Mesocortical, 2. Nigrostriatal, 3. Tubero-infundibular, 4. Medullary-periventricular[1]

Question 30

Where is dopamine β-hydroxylase located and what does it do?

Answer 30

Dopamine β-hydroxylase is bound to the inner surface of synaptic vesicles and converts dopamine to norepinephrine[1]

Question 31

How is epinephrine synthesized from norepinephrine?

Answer 31

Epinephrine is made by methylating norepinephrine using S-adenosyl methionine (SAM) as the methyl donor[1]

Question 32

What is the precursor for serotonin synthesis?

Answer 32

Tryptophan is the precursor for serotonin synthesis[1]

Question 33

How do neuropeptides differ from small molecule neurotransmitters?

Answer 33

Neuropeptides are synthesized in the cell body, stored in large dense core vesicles, have higher potency, longer-lasting effects, and often act through G-protein coupled receptors[1]

Question 34

What are the main differences between ionotropic and metabotropic receptors?

Answer 34

Ionotropic receptors are fast-acting and directly coupled to ion channels, while metabotropic receptors are slower-acting and coupled to G proteins[1]

Question 35

Name five types of ionotropic receptors

Answer 35

Acetylcholine, glutamate (NMDA, AMPA, & Kainate), GABA, glycine, and serotonin receptors[1]

Question 36

What are the three groups of metabotropic glutamate receptors and their effects?

Answer 36

Group I (mGlu1, mGlu5) potentiate NMDAR-induced Ca2+ influx; Groups II and III (mGlu2-4, mGlu6-8) reduce NMDAR-induced Ca2+ influx[1]

Question 37

What is the function of choline acetyltransferase?

Answer 37

Choline acetyltransferase catalyzes the synthesis of acetylcholine from acetyl-CoA and choline[1]

Question 38

How does organophosphate poisoning affect the nervous system?

Answer 38

Organophosphates inhibit acetylcholinesterase

Question 39

What is the role of glutamic acid decarboxylase in neurotransmitter synthesis?

Answer 39

Glutamic acid decarboxylase catalyzes the synthesis of GABA from glutamate[1]

Question 40

What are the main catecholamine neurotransmitters?

Answer 40

Dopamine

Question 41

How does the mesolimbic-mesocortical dopamine tract function?

Answer 41

The mesolimbic-mesocortical dopamine tract is involved in emotional (mesolimbic) and cognitive (mesocortical) circuitry[1]

Question 42

What is the role of the nigrostriatal dopamine tract?

Answer 42

The nigrostriatal dopamine tract is involved in the control of movement and is affected in Parkinson's Disease[1]

Question 43

How does the tubero-infundibular dopamine tract affect hormone secretion?

Answer 43

The tubero-infundibular dopamine tract is involved in regulating hormone secretion

Question 44

What is the function of the medullary-periventricular dopamine tract?

Answer 44

The medullary-periventricular dopamine tract is involved in the regulation of eating and may be related to obesity and diabetes[1]

Question 45

Where are norepinephrine-producing neurons primarily located in the CNS?

Answer 45

Norepinephrine-producing neurons are primarily located in the locus coeruleus[1]

Question 46

How do Selective Serotonin Reuptake Inhibitors (SSRIs) work?

Answer 46

SSRIs block the reuptake of serotonin from the synapse

Question 47

What are the main differences between small molecule neurotransmitters and neuropeptides?

Answer 47

Neuropeptides are synthesized from mRNA in the cell body, stored in large dense core vesicles, and generally have higher potency and longer-lasting effects than small molecule neurotransmitters[1]

Question 48

How many subtypes of muscarinic acetylcholine receptors are there?

Answer 48

There are five subtypes of muscarinic acetylcholine receptors (m1 - m5)[1]

Question 49

What are the main types of adrenergic receptors?

Answer 49

The main types of adrenergic receptors are alpha (α1, α2) and beta (β1, β2, β3)[1]

Question 50

How do Group I metabotropic glutamate receptors affect intracellular signaling?

Answer 50

Group I mGluRs (mGlu1, mGlu5) activate phospholipase C (PLC), leading to increased inositol triphosphate (IP3) and calcium signaling[1]