Dopamine Systems - 29

Question 1

What is Dopamine?

Answer 1

A Monoamine neurotransmitter

Question 2

What does dopamine do?

Answer 2

Translates thoughts into action : decision making, goal directed behavior, movement : affects mood

Question 3

What are the pathways of the brand for Dopamine?

Answer 3

Mesocortial, Mesolithic, Nigrostriatal, Tuberoinfundibular, Chemoreceptors trigger zone

Question 4

What is the Mesocortical pathway in control of?

Answer 4

Cognition

Question 5

What is the Mesolithic pathway in control of?

Answer 5

Integration of emotional responses; “complex reward-oriented behavior”

Question 6

What is the Nigrostriatal pathway in control of?

Answer 6

Motor; planning and execution; “automated behaviors”

Question 7

What is the Tuberoinfundibular pathway in control of?

Answer 7

Inhibits prolactin release and regulates growth hormone release from the pituitary

Question 8

What is the chemoreceptors trigger zone in control of?

Answer 8

Gag/vomit reflex - nausea

Question 9

Where is dopamine synthesized?

Answer 9

In the pre-synaptic terminals

Question 10

Where is dopamine stored?

Answer 10

In vesicles of the pre-synaptic terminals

Question 11

What controls the release of dopamine?

Answer 11

Action potentials

Question 12

What kind of receptors are dopamine receptors?

Answer 12

GPCRs

Question 13

Are dopamine receptors excitatory or inhibitory?

Answer 13

They can be either

Question 14

What does the dopamine transporter do?

Answer 14

Removes dopamine from the synapse for repackaging/use

Question 15

What are the molecules of the dopamine pathway?

Answer 15

Tyrosine, L-DOPA, Dopamine, DOPAC, HVA

Question 16

What are the enzymes of the Dopamine pathway?

Answer 16

Tyrosine hydroxylase, DOPA Decarboxylase, MAO, COMT

Question 17

What are the steps of the Dopamine pathway?

Answer 17

Tyrosine (Tyrosine Hydroxylase) L-DOPA (DOPA Decarboxylase) Dopamine (MAO) DOPAC (COMT) HVA

Question 18

What happens if you delete the Dopamine Transporter?

Answer 18

You’d have more dopamine in the clefts/increased motor activity

Question 19

What is Parkinson’s Disease?

Answer 19

A neurodegenerative disease resulting from a loss of dopamine neurons

Question 20

What would you notice in a brain with Parkinson’s?

Answer 20

Lack of pigmentation in the Substantia Nigra (no oxidation of dopamine)

Question 21

What motor features do Parkinson’s Disease patients have?

Answer 21

“TRAP” : Tremor (when at rest) : Rigidity : A(Brady)kinesia (absense of movement) : Postural instability :::: Also, trouble swallowing, difficulty initiating walking, “masked” facial expressions

Question 22

Does Parkinson’s Disease decrease life expectancy?

Answer 22

NO, but increased accidental death

Question 23

What are some NON-motor symptoms of Parkinson’s?

Answer 23

Depression/anxiety, pain, speech/swallowing problems, sleep disturbances, autonomic symptoms

Question 24

What are examples of “autonomic symptoms” of Parkinson’s?

Answer 24

Constipation, orthostasis (lightheaded upon standing), sexual dysfunction, sweating abnormalities

Question 25

Who gets Parkinson’s?

Answer 25

1-2% over 65, 3-5% over 85; ~4% <50yrs

Question 26

Is there an increased risk of PD in relatives?

Answer 26

Slight increase in first-degree relatives

Question 27

T/F All cases of Parkinson’s Disease are related to an identified single gene

Answer 27

F - <10% of cases are related to an identified single gene

Question 28

What are environmental causes of Parkinson’s?

Answer 28

pesticides, head injury, infection, MPTP, Manganese (may be viral/bacterial!!!)

Question 29

What are some things that decrease the risk of Parkinson’s?

Answer 29

Smoking, and Caffeine

Question 30

What are the genetic causes of Parkinson’s Disease?

Answer 30

Increased risk in family members, multiple genetic risk factors

Question 31

How do we treat Parkinson’s?

Answer 31

Treat the symptoms. Improve function/QoF. Replace brain dopamine (give L-Dopa)

Question 32

What can you do to slow/reverse the effects of Parkinson’s?

Answer 32

There is no known treatment to slow or reverse the progression of Parkinson’s

Question 33

What things can PD treatment help with?

Answer 33

Treat bradykinesia/rigidity, tremor, sometimes postural/gait treated

Question 34

What drug is given to replace Dopamine?

Answer 34

L-DOPA (Levodopa)

Question 35

Why cant we just give Dopamine instead of the precursor?

Answer 35

Dopamine will be broken down in the periphery before getting into the brain.

Question 36

What treatments are there that are aimed at the dopamine system?

Answer 36

Replace Dopamine : Enhance Dopamine : Dopamine receptor agonists

Question 37

How do you enhance Dopamine?

Answer 37

Prevent the conversion of L-DOPA to Dopamine in the periphery (Dopamine cant pass BBB)

Question 38

What drugs “enhance dopamine”?

Answer 38

Carbidopa, Entacapone, Rasagiline, Selegiline, and Low dose cocaine

Question 39

What is the name for the drug that combines Carbidopa and Levodopa? Why would you do this?

Answer 39

Sinemet; Carbidopa stops the breakdown of L-DOPA in the periphery, and Levodopa IS L-DOPA

Question 40

What is an example of a dopamine receptor agonist?

Answer 40

Pramipexole

Question 41

What effects does Levodopa have?

Answer 41

CNS effects: Reduced bradykinesia/rigidity, antidepressant ::: Endocrine effects: decreased prolactin release ::: GI: Nausea/vomiting (take w/ food) ::: CARDIOVASCULAR SYSTEM: Orthostatic hypotension, cardiac stimulation

Question 42

How do the motor complication of Parkinson’s progress from early to advanced?

Answer 42

Early: Long-duration of L-DOPA effect with little dyskinesias ::: Moderate: Short-duration of effect with some dyskinesias ::: Advanced: Short-duration with consistent dyskinesias

Question 43

What are some of the Pros and Cons to using a Dopamine Receptor Agonist?

Answer 43

Lasts longer than Levodopa (smooths wearing off feeling when used together); More side effects

Question 44

What are some side effects of Dopamine Receptor Agonists?

Answer 44

Sleep attacks, Impulse Control Disorders (compulsive gambling...)

Question 45

What are som “other Pharmacological approaches” to PD?

Answer 45

Benztropine (Cogentin) and Amantadine (Symmetrel)

Question 46

What is Benztropine?

Answer 46

Cogentin; Muscarinic antagonist : cognitive side effects/fatigue

Question 47

What is Amantadine?

Answer 47

Symmetrel; antiviral; increases dopamine release/reduces reuptake

Question 48

What is the most modern treatment for Parkinson’s? When is it used?

Answer 48

Deep Brain Stimulation : when pharmacological therapies fail

Question 49

Contraindications for Deep Brain Stimulation:

Answer 49

Cognitive impairment; postural instability; uncontrolled depression

Question 50

What is Huntington’s Disease?

Answer 50

Neurodegenerative disorder: Genetic disease

Question 51

What inheritance is there for Huntington’s?

Answer 51

Autosomal dominant: Trinucleotide repeat on Chromosome 4

Question 52

When does Huntington’s onset?

Answer 52

Between 20-40

Question 53

What are some characteristics of Huntington’s?

Answer 53

Demonstrates anticipation; Psychiatric disturbances (1st); Chorea; dystonia; dementia/DEATH

Question 54

What is Chorea?

Answer 54

Jerky/involuntary movements of the shoulder/hips/face

Question 55

What are some psychiatric symptoms of Huntington’s?

Answer 55

Depression, psychosis, bipolar

Question 56

How do we treat Huntington’s?

Answer 56

Treat Chorea with Dopamine ANTAGONISTS ::: Treat bradykinesia/rigidity with Dopamine AGONISTS

Question 57

What are the main dental implication of Huntington’s and Parkinson’s?

Answer 57

Exam difficulty, hygiene, and drug interactions