Exam 2 - Catecholamines

Question 1

The rate-limiting enzyme in the synthesis of catecholamines is:

Answer 1

tyrosine hydroxylase

Question 2

What is the synthesis of catecholamines?

Answer 2

tyrosine, need tyrosine hydroxylase -> DOPA, needs AADC -> Dopamine, needs dopamine betahydroxylase -> norepinephrine

Question 3

6-hyroxydopamine is a ________ used to ________.

Answer 3

neurotoxin, damage catecholamine neurons

Question 4

Catecholamines

Answer 4

include dopamine, norepinephrine, and epinephrine

Question 5

What transporter is responsible for the reuptake of catecholamines? What are the two types?

Answer 5

• vesicular monoamine transporter (VMAT)
• VMAT 1 and VMAT 2

Question 6

Resperine

Answer 6

• blocks reuptake of dopamine, blocks VMAT
• lowers BP and has a sedative effect

Question 7

What does the release of catecholamines cause?

Answer 7

an increase of locomotor activity

Question 8

What does inactivation of catecholamines depend on?

Answer 8

1) reuptake by dopamine transporter and norepi. transporter
2) metabolic breakdown by enzymes COMT and MAO

Question 9

What does the breakdown of catecholamines by COMT and MAO cause?

Answer 9

• dopamine gets turned into HVA
• norepi gets turned into MHPG and VMA

Question 10

What is the nigrostriatal pathway?

Answer 10

• originates in substantia nigra and goes to the caudate-putamen
• play an important role in the control of movement
• this pathway is damaged in parkinson’s disease

Question 11

Parkinson’s disease

Answer 11

• neurodegenerative disease
• occurs when the cells that produce dopamine (in substantia nigra) die
• no cure; L-dopa can be offered to replace dopamine; inhibition of dopamine metabolism by MAO type B inhibitors; anticholinergics that block ACH to prevent tremors; surgery

Question 12

What are the symptoms of Parkinsons?

Answer 12

• M - muscle rigidity
• I - impaired balance
• S - slowness and stiffness
• T - (resting) tremors

Question 13

MPTP

Answer 13

• neurotoxin that causes symptoms of parkinsons
• causes a loss of neurons in the substantia nigra

Question 14

Mesolimbic system

Answer 14

• originates in the ventral tegmental area and travels to the nucleus accumbens
• important in addiction

Question 15

Mesocortical system

Answer 15

• originates in ventral tegmental area and projects to the cerebral cortex
• important in addiction

Question 16

Explain Olds and Milners experiment

Answer 16

• identified the certain brain sites where direct electrical stimulation is reinforcing

Question 17

Dopamine receptors

Answer 17

• metabotropic
• D1 to D5

Question 18

What is the difference between the D1 and D2 receptors?

Answer 18

• D1 increased CAMP synthesis
• D2 decreased CAMP synthesis

Question 19

What are the dopamine agonists? What receptor do they affect?

Answer 19

• apomorphine - D1 and D2
• SKF 38393 - D1
• quinpirole - D2 and D3
• agonists cause an increase in activity, also caused by giving 6-OHDA

Question 20

Dopamine antagonists ________ locomotion. What is an example of a dopamine antagonist? What does high doses of this antagonist do?

Answer 20

• decrease
• haloperidol
• catalepsy (waxy flexbility)

Question 21

Noradrenergic system

Answer 21

• originates in the locus coeruleus and provides input to the cortex, limbic system, thalamus, and hypothalamus

Question 22

What is the role of the locus coeruleus?

Answer 22

vigilance/arousal

Question 23

Adrenergic receptors, what are the two subtypes? Which inhibit and enhance the release of CAMP?

Answer 23

• metabotropic
• alpha and beta
• beta receptors enhance the synthesis of CAMP
• alpha receptors inhibit the rate of CAMP

Question 24

Adrenergic agonists _________ arousal and eating behavior.

Answer 24

stimulate/increase

Question 25

Where are the neural mechanisms for eating located? What is responsible for responses in this area?

Answer 25

• hippocampus, specifically the paraventricular nucleus
• alpha 2 receptors

Question 26

What effect does norepi. have on eating?

Answer 26

• induces eating