Week 4 - Summary of Selected Neurotransmitters (Word Doc)

Question 1

Where do you find Acetylcholine? (5x)

Answer 1

1) Lower motor neuron synapses at neuromuscular junction (skeletal muscle fibers) to bring about contraction
2) Autonomic Ganglia: Preganglionic neuron synapses with postganglionic neurons
3) Parasympathetic neuron synapses with target organs and tissues
4) Some selected sympathetic postganglionic synapses with target organs
5) Many CNS (brain and spinal cord) synapses

Question 2

How is Acetylcholine released?

Answer 2

By exocytosis secondary to opening of voltage-gated calcium channels and inward calcium ion flow (calcium-dependent exocytosis)

Question 3

What 2x types of cholinergic receptors does Acetylcholine bind to?

Answer 3

1) Nicotinic
2) Muscarinic

Question 4

What receptors does Acetylcholine bind to?

Answer 4

Cholinergic Receptors

Question 5

What are Nicotinic receptors divided into?

Answer 5

1) Nicotinic Type-1
2) Nicotinic Type-2

Question 6

What are Nicotinic Receptors?

Answer 6

Very fast responding ligand-gated ion channels with short duration of activity (1-2 msec)

Question 7

Where do you find Nicotinic Type-1 receptors?

Answer 7

Neuromuscular Junction

Question 8

Where do you find Nicotinic Type-2 receptors?

Answer 8

Autonomic Ganglionic Synapses

Question 9

What are Muscarinic Receptors?

Answer 9

G-protein coupled receptors that have a long duration of activity (100-250 msec)

Question 10

What are 3x examples of Muscarinic Receptors?

Answer 10

1) Diacylglycerol (DAG)
2) Inositol triphosphate (IP3)
3) Protein Kinase

Question 11

What inactivates Acetylcholine?

Answer 11

Acetylcholinesterase

Question 12

Where do you find Norepinephrine? (2x)

Answer 12

1) Sympathetic postganglionic neuron synapses with target organ and tissue synapses
2) Many central nervous system synapses (i.e. synapses of locus coeruleus pathways – causes alertness)

Question 13

Where do you find Dopamine?

Answer 13

Central nervous system: Nigrostriatal pathways (i.e. synapses of neurons from substantia nigra with corpus striatum)

Question 14

Where do you find Epinephrine?

Answer 14

Synthesized and secreted from Adrenal Medulla gland (only place)

Question 15

What is the role of Epinephrine? (2x)

Answer 15

• Released from the Adrenal Medulla into the bloodstream and makes its way to sympathetic synapses
• Intensifies the overall sympathetic response

Question 16

What happens if a patient has an Adrenalectomy?

Answer 16

No synthesis of Epinephrine
(norepinephrine is converted to epinephrine in the adrenal gland)

Question 17

What is Epinephrine classified as?

Answer 17

Neurohormone
(neurotransmitter and hormone)

Question 18

How are Catecholamines synthesized? (5x)

Answer 18

Tyrosine → Dihydroxyphenylalanine (L-DOPA) → Dopamine → Norepinephrine → Epinephrine (only in the adrenal medulla)

*Each arrow represents an enzymatic conversion

Question 19

How are Catecholamines released?

Answer 19

By Calcium-Dependent Exocytosis

Question 20

What receptors do Norepinephrine and Epinephrine bind to?

Answer 20

Adrenergic Receptors

Question 21

Adrenergic Receptors mostly operate through what?

Answer 21

G-proteins that stimulate or inhibit second messengers and protein kinases

Question 22

What are the 4x specific Adrenergic Receptors?

Answer 22

1) Alpha-1 (α-1)
2) Alpha-2 (α-2)
3) Beta-1 (β-1)
4) Beta-2 (β-2)

*There is a Beta-3, but it’s not listed

Question 23

What does Dopamine bind with?

Answer 23

Dopaminergic Receptors
(G-protein coupled receptors)

Question 24

There are at least how many Dopamine receptors that have been identified?

Answer 24

5

Question 25

What are the 2x primary Dopamine receptors and what do they do?

Answer 25

1) D1: activate adenyl cyclase 2) D2: inhibit adenyl cyclase

Question 26

What percentage of Catecholamines are taken up into axoplasm of presynaptic neuron and restored in synaptic vesicles?

Answer 26

80%

Question 27

What metabolizes Catecholamines?

Answer 27

Monoamine Oxidase (MAO)

Question 28

How are Catecholamines taken up into the axoplasm of the presynaptic neuron?

Answer 28

By a Re-Uptake Pump

Question 29

Where do you find Serotonin? (2x)

Answer 29

In the Central Nervous System (CNS), specifically: - Brainstem (Raphe nuclei -- which projects to higher brain centers, lower brain centers, and spinal cord) - Various synapses in the limbic system (emotions & memory)

Question 30

What is another name for Serotonin?

Answer 30

5-hydroxytryptamine (5HT)

Question 31

How is Serotonin released? (2x)

Answer 31

- By Calcium-Dependent Exocytosis - Often released with other neurotransmitters (intensifies or inhibits the response in post-synaptic membrane)

Question 32

What other 6x possible neurotransmitters is Serotonin released with?

Answer 32

1) Acetylcholine 2) Norepinephrine 3) Dopamine 4) Substance P 5) Enkephalins 6) Prostaglandins

Question 33

What is the name of a substance that is often released along with other neurotransmitters?

Answer 33

Neuromodulator

Question 34

There are at least how many Serotonin receptors?

Answer 34

7

Question 35

How is Serotonin synthesized? (4x)

Answer 35

L-tryptophan --> 5-hydroxytryptophan --> Serotonin --> Melatonin (pineal gland only)

Question 36

Most of the Serotonin receptors are excitatory or inhibitory?

Answer 36

Inhibitory

Question 37

Serotonin is taken back up into the axoplasm by what?

Answer 37

A Re-Uptake Pump

Question 38

What is the full name of SSRI?

Answer 38

Selective Serotonin Re-Uptake Inhibitors

Question 39

What does an SSRI do? (4x)

Answer 39

- Decreases uptake from the synapse - More available Serotonin in the synapse - Causes increase in post-synaptic responses (inhibitory) - Improves mood by decreasing symptoms of depression/anxiety

Question 40

What is the full name of GABA?

Answer 40

Gamma Aminobutyric Acid

Question 41

Where do you find GABA?

Answer 41

- Widely throughout the Central Nervous System (CNS) - Some axoaxonal synapses in the Peripheral Nervous System (PNS)

Question 42

What 2x specific locations are GABA found?

Answer 42

1) Diencephalon 2) Telencephalon

Question 43

What 4x specific sub-locations are GABA found in the Diencephalon?

Answer 43

1) Thalamus 2) Subthalamus 3) Epithalamus 4) Hypothalamus

Question 44

What 3x specific sub-locations are GABA found in the Telencephalon?

Answer 44

1) Cerebral hemispheres 2) Basal nuclei 3) Olfactory bulb

Question 45

How is GABA released?

Answer 45

By Calcium-Dependent Exocytosis

Question 46

How many GABA receptors have been identified?

Answer 46

2

Question 47

What are the 2x GABA receptors?

Answer 47

1) GABA-A 2) GABA-B

Question 48

Where are GABA-A receptors and what do they do?

Answer 48

- Where: Post-synaptic membranes - What: Opens ligand-gated chloride channels (results in membrane hyperpolarization) [inhibition]

Question 49

Where are GABA-B receptors and what do they do?

Answer 49

- Where: Presynaptic membranes - What: Modulates neurotransmitter release (norepinephrine, dopamine, serotonin, glutamate) -- Decreases amount of neurotransmitter released into the synapse

Question 50

What drugs take advantage of GABA receptors?

Answer 50

- Propofol - Benzodiazepines

Question 51

GABA is always _________

Answer 51

INHIBITORY!

Question 52

Glutamate is always _________

Answer 52

EXCITATORY!

Question 53

What is Glutamate?

Answer 53

An excitatory neurotransmitter that is the primary neurotransmitter for transmission of acute, fast, prickling pain

Question 54

Where do you find Glutamate?

Answer 54

Throughout Central Nervous System (CNS)

Question 55

How is Glutamate released?

Answer 55

By Calcium-Dependent Exocytosis

Question 56

What are the 3x receptors that Glutamate binds to?

Answer 56

1) NMDA 2) QA 3) KA *Rapid ligand-gated ion channels that increase sodium inflow and excite post-synaptic membrane

Question 57

What drug is an NMDA antagonist?

Answer 57

Ketamine

Question 58

What is the full name of NMDA?

Answer 58

N-methyl-D-aspartate

Question 59

What is the full name of QA?

Answer 59

Quisqualate Receptors

Question 60

What is the full name of KA?

Answer 60

Kainate Receptors

Question 61

Blocking NMDA receptors does what to pain?

Answer 61

Decreases pain

Question 62

What is Substance P?

Answer 62

A primary neurotransmitter for the transmission of slow, long-term, suffering pain (maintains the transmission)

Question 63

How is Substance P released?

Answer 63

By Calcium-Dependent Exocytosis

Question 64

What receptors does Substance P bind to?

Answer 64

Neurokinin Type-1 receptors (NK1-receptor)

Question 65

What are Neurokinin Type-1 receptors (NK1-receptor)?

Answer 65

Coupled G-proteins that leads to prolonged excitation of postsynaptic neuron

Question 66

What is another name for Inhibitory Neuropeptides?

Answer 66

Endogenous Opioid Peptides

Question 67

What are the 3x types of Inhibitory Neuropeptides/Endogenous Opioid Peptides?

Answer 67

1) Endorphins 2) Enkephalins 3) Dynorphins

Question 68

Where do you find Inhibitory Neuropeptides/Endogenous Opioid Peptides?

Answer 68

- Widely throughout the Central Nervous System (CNS) - EX: Cerebral cortices, brain stem, diencephalon, limbic system, basal nuclei, cerebellum, pituitary gland, gray matter of spinal cord, and others

Question 69

How are Inhibitory Neuropeptides/Endogenous Opioid Peptides released?

Answer 69

By Calcium-Dependent Exocytosis

Question 70

What 3x receptors do Inhibitory Neuropeptides/Endogenous Opioid Peptides bind to? What are the receptors each specific for?

Answer 70

1) Mu (µ) -- specific for endorphins 2) Kappa (κ) -- specific for dynorphins 3) Delta (δ) -- specific for enkephalins

Question 71

What type of response does the Inhibitory Neuropeptides/Endogenous Opioid Peptides cause?

Answer 71

INHIBITORY! Through G-protein coupled receptors

Question 72

What 2x receptors activate the potassium channels (cell membrane hyperpolarization)?

Answer 72

1) Mu 2) Delta

Question 73

What receptors inactivate calcium channels (decreased inflow of calcium ions and decreased activity of intracellular calcium-dependent processes)?

Answer 73

Kappa

Question 74

True or False: All neuropeptides have little potency and cause a prolonged target cell response, sometimes for days, weeks, or months

Answer 74

FALSE! *All neuropeptides are VERY potent!

Question 75

What causes a release of the endogenous opioid peptides?

Answer 75

Anything that makes you happy (i.e. working out, eating amazing food, etc)

Question 76

How do you take advantage of the Mu, Delta, and Kappa receptors?

Answer 76

Opioids *Give exogenous opioids that binds to these receptors, which inhibits pain transmission

Question 77

What are some other neurotransmitters and neuromodulators? (7x)

Answer 77

1) Glycine 2) Nitric Oxide 3) Angiotensin II 4) Cholecystokinin 5) Bradykinin 6) Histamine 7) Adenosine Triphosphate (ATP)