Exam 2 (Lecture 12/13)

Question 1

Sympathetic

Answer 1

Fight or flight

Thoracolumbar

Question 2

Parasympathetic

Answer 2

Rest and Digest

Craniosacral

Question 3

Neuron

Answer 3

fundamental units of the nervous system for transforming and relaying the electrical signals

Question 4

Astrocyte

Answer 4

provides biochemical support of endothelial cells that form the blood–brain barrier (BBB),
supplies nutrients to the nervous tissue

Question 5

Oligodendrocyte

Answer 5

provides he axon of long-range projection neurons insulation by a myelin sheath

Question 6

Vasculature

Answer 6

supplies oxygen and nutrients, the brain would quickly suffer damage from any stoppage
in blood supply

Question 7

Myelin Sheath

Answer 7

insulates the projections of neurons and increases conductivities.

Question 8

Schwann Cells found in

Answer 8

PNS

Question 9

Oligodendrocytes found in

Answer 9

CNS

Question 10

Blood Brain Barrier

Answer 10

functions as a border that prevents solutes in the circulating blood from non-selectively to avoid toxic substance coming in.

Question 11

Soma

Answer 11

cell body; perikaryon

contains nucleus and most of cytoplasm
features of active secretory cell (large nucleus, lots of endoplasmic reticulum, prominent Golgi)

Question 12

Dendrites

Answer 12

information “receiving” elements

fine processes extending from soma in tree-like arrangement;

can be many along with soma comprises receptive field of neuron

Question 13

Axon

Answer 13

information “transmitting” element

a thin process extending from axon hillock (initial segment of axon as it leaves soma) along which action potential is conducted

one per neuron: can be long or short, single or branched, myelinated or not myelinated

Question 14

Axon Terminal

Answer 14

(terminal boutons; presynaptic terminals)
swelling of axon at its terminal end, enriched with vesicles containing neurotransmitter

forms “synaptic contact” with receptive region of
a second neuron (i.e. a postsynaptic neuron)

swellings filled with vesicles can also occur along length of axon giving rise to a beaded appearance (these swellings are called varicosities); may form synapses

Question 15

Basic Elements of chemical neurotransmission

Answer 15

1. Arrival of action potential at axon terminal
2. Depolarization of axon terminal membrane
3. Influx of Ca++ into terminal via voltage-gated Ca++ channels
4. Fusion of vesicles with terminal membrane
5. Extrusion of vesicle contents into synapse: exocytosis
6. Binding of transmitter to postsynaptic receptors
7. Opening of chemically-gated ion channel
8. Change in membrane potential
   EPSP if Na+ Channels open (depolarization)
   IPSP if K+ or Cl- channels open (hyperpolarization)
9. Termination of transmitter action by re-uptake into presynaptic terminal, or by enzymatic degradation, or both

Question 16

Criteria for Neurotransmitter

Answer 16

1. Substance must be present in presynaptic neuron and its terminals (precursors and synthetic enzymes should also be present)
2. Substance must be released from presynaptic terminals with neuronal activity
3. Effects of the applied substance on a target neuron (postsynaptic cell) must be same as effects of stimulating the presynaptic neuron
   - antagonist of the substance should also block both
4. Mechanism for the transmitter candidate’s inactivation must be present in the synapse

Question 17

SNARE Cycle

Answer 17

1. Synaptobrevin interacts with two plasma membrane target proteins, the transmembrane protein syntaxin and the peripheral membrane protein SNAP-25.
2. The three proteins form a tight complex bringing the vesicle and presynaptic membranes in close apposition (see part B). Munc18 binds to the SNARE complex.
3. Calcium influx triggers rapid fusion of the vesicle and plasma membranes; the SNARE complex now resides in the plasma membrane.
4. Two proteins, NSF and SNAP (unrelated to SNAP-25), bind to the SNARE complex and cause it to dissociate in an ATP-dependent reaction.

Question 18

Neurotransmitter structures

Answer 18

Amines
Purines
Monoamines
Amino Acids
Endocannabinoids
Peptides

Question 19

Linked to cationic channels (excitatory)

Answer 19

Glutamate

Aspartate

Question 20

Linked to anionic channels (inhibitory)

Answer 20

GABA

Glycine

Question 21

Glycine

Answer 21

• Receptor antagonist: strychnine
• Mechanism of action: similar to GABA (i.e.
increases Cl- conductance)
• Major inhibitory transmitter in spinal cord

Question 22

γ-Aminobutryic acid (GABA) cycle

Answer 22

• Reuptake (GAT1)
• Transport into glial cells (GAT3)
• Conversion to glutamine (GS)
• Transport into GABAergic neuron (SAT)
• Package into vesicles (VGAT)

Question 23

Glutamic acid (glutamate) cycle

Answer 23

• Reuptake (GLT)
• Transport into glial cells (GLT/GLAST)
• Conversion to glutamine (GS)
• Transport into GABAergic neuron (SAT)
• Package into vesicles (VGLUT)

Question 24

Glutamate synthesis

Answer 24

a dietary amino acid, also synthesized in neurons from precursor glutamine

Question 25

Glutamate receptor subtypes

Answer 25

NMDA, AMPA, Kainate = ligand-gated | mGLuR 1-8 = metabotropic

Question 26

Glutamate receptor angonists

Answer 26

``` monosodium glutamate (MSG, food additive, flavor enhancer) Kainic acid (potent neurotoxin, excites neurons to death) ```

Question 27

Glutamate mechanism of action

Answer 27

increases in membrane cation (Na+ and Ca++) permeability thereby depolarizing neuronal membrane

Question 28

LTP

Answer 28

Long Term potentiation Increase AMPA Synaptic strengthening Post synaptic end senses Glutamate, increases receptors to adjust, they stay for a period

Question 29

LTD

Answer 29

Long term depression Synaptic weakening decreasing AMPA receptors get internalized, fewer at surface

Question 30

Acetylcholine (ACh) synthesis

Answer 30

Choline + Acetyl Coenzyme A = Acetylcholine + Coenzyme A via Choline acetyltransferase

Question 31

ACh inactivation

Answer 31

Acetyle Choline = Choline + Acetate via acetylcholinesterase

Question 32

2 Classes Cholinesterase enzymes

Answer 32

acetylcholinesterase "true" - neural tissue, in synaptic cleft Butyrlcholinesterase "pseudo" - plasma, liver

Question 33

ACh receptors

Answer 33

Nicotinic = ligand-gated ion channel, agonist is nicotine Muscarinic = g-protein coupled M1-M5 subtypes, agonist is muscarine

Question 34

ACh cycle

Answer 34

* Degradation (AChE) * Transport into presynaptic site (CHT) * Conversion to ACh (ChAT) * Package into vesicles (VAChT)

Question 35

Catecholamine synthesis

Answer 35

Tyrosine -> Dopa via Tyrosine Hydroxylase (TH) Dopa -> Dopamine via AADC (or DOPA decarboxylase) Dopamine -> Norepinephrine vis DBH Norepinephrine -> Epinephrine via PNMT

Question 36

Catecholamine inactivation

Answer 36

1. Re-uptake = Rapid (blocked by cocaine and tricyclic antidepressants 2. Enzymatic Degradation = slower 2 enzymes MAO and COMT

Question 37

MAO

Answer 37

Monoamine oxidase blocked by drugs known as MAO inhibitors primarily intraneuronal, cytoplasm of nerve terminal

Question 38

COMT

Answer 38

Catechol-o-methyltransferase Extraneuronal metabolism

Question 39

Catecholamine Cycle

Answer 39

Reuptake (DAT/NET) | Package into vesicles (VMAT2)

Question 40

dopamine receptors

Answer 40

All G-protein coupled, D1-D5

Question 41

Norepinephrine receptors

Answer 41

two families, designated α and β, all G- protein coupled

Question 42

Serotonin (5-HT) synthesis

Answer 42

Tryptophan -> 5-hydroxytryptophan via TPH | 5-hydroxytryptophan - > Serotonin via AADC

Question 43

Serotonin cycle

Answer 43

Reuptake (SERT) | Package into vesicles (VMAT2)

Question 44

Serotonin receptors

Answer 44

5HT3 - ligand-gated ion | All others are G-protein

Question 45

Histamine Synthesis

Answer 45

Histidine -> Histamine via Histidine Decarboxylase

Question 46

Histamine Metabolism

Answer 46

histamine N-methyltransferase

Question 47

Glutamate apoptosis (Excitotoxicity

Answer 47

All signaling activated by calcium, leading to cell death

Question 48

Ultra Short neurons

Answer 48

retina and olfactory bulb neurons

Question 49

Intermediate length neurons

Answer 49

Hypothalamus to pituitary (mediate endocrine functions)

Question 50

dopaminergic pathways

Answer 50

A9, motor functions, substantia nigra pars compact to striatum A10, mediate pleasure and reward, Ventral Tegmental area to limbic areas of brain

Question 51

Norepinephrine pathways

Answer 51

A1,A2,A5,A7

Question 52

Serotonergic pathway

Answer 52

begins Raphe nuclei

Question 53

H1 receptor

Answer 53

antihistamine target

Question 54

H2 receptor

Answer 54

Gastric acid secretion target

Question 55

Peptide transmitters

Answer 55

mRNA -> rough ER to make -> Golgi to pack -> move to synapse via large dense-core vesicles -> no reuptake, catabolic peptidases turn into inactive metabolite once released in synapse. Need more control/ high frequency for release not CA like other neurotransmitters.

Question 56

GABA A/C

Answer 56

ionotropic receptor - fast

Question 57

GABA B

Answer 57

G protein receptor

Question 58

Cholinergic Pathways

Answer 58

Originate in Nucleus Basalis of Meynert

Question 59

Where do Norepinephrine neurons originate?

Answer 59

Locus Ceruleus