Introduction.

Question 1

What is an agonist?

Answer 1

A substance that binds to a receptor and activates it.

Question 2

What is an antagonist?

Answer 2

A substance that binds to a receptor and either blocks it from functioning or it reduces the effects of that receptor.

Question 3

Adrenergic agonists will stimulate what kind of receptors?

Answer 3

Adrenergic receptors.

Question 4

What physiological responses are produced when an adrenergic agonist binds to an adrenergic receptor?

Answer 4

Physiological responses that are similar to those of catecholamines.

Question 5

What are the 2 classes of actions that adrenergic agonists can have?

Answer 5

Direct effects.

Indirect effects.

Question 6

What are the effects of direct adrenergic agonists?

Answer 6

They bind to and stimulate adrenergic receptors.

Question 7

What are the effects of indirect adrenergic agonists?

Answer 7

They lead to the release of catecholamines from adrenergic neurons.

Question 8

What is the major neurotransmitter of adrenergic neurotransmission?

Answer 8

Norepinephrine.

Question 9

Where is norepinephrine synthesised and stored?

Answer 9

At the terminal end of the pre-synaptic neuron.

Question 10

What is the first step of norepinephrine synthesis in the pre-synaptic neuron?

Answer 10

Tyrosine is taken from the extracellular environment and converted to DOPA within the cell.

Question 11

What is the rate limiting step in tyrosine formation?

Answer 11

The conversion of tyrosine to DOPA.

Question 12

What enzyme converts tyrosine to DOPA?

Answer 12

Tyrosine hydroxylase.

Question 13

What is the 2nd step of norepinephrine formation after DOPA has been formed?

Answer 13

DOPA is converted by DOPA decarboxylase to dopamine.

Question 14

What is the 3rd step of norepinephrine formation after dopamine has been formed?

Answer 14

Dopamine is converted to norepinephrine by dopamine beta-hydroxylase.

Question 15

What steps of norepinephrine formation are carried out in the cytoplasm?

Answer 15

All of the steps that lead to the formation of dopamine.

Question 16

What steps of norepinephrine formation are carried out in the synaptic vesicle?

Answer 16

The conversion of dopamine to norepinephrine takes place in the synaptic vesicle.

Question 17

When will the vesicles containing norepinephrine be released?

Answer 17

Following an action potential.

Question 18

What happens after norepinephrine has been released into the synaptic cleft?

Answer 18

It travels to the post synaptic neuron and binds to adrenergic receptors on the cell membrane.

Question 19

What happens once norepinephrine has bound to to adrenergic receptors on the post-synaptic cell membrane?

Answer 19

It causes an action potential to be generated in the post-synaptic neuron and this leads to cellular effects.

Question 20

What happens to norepinephrine in the synaptic cleft after it has induced cellular responses in the post-synaptic neuron?

Answer 20

It is either taken back into the pre-synaptic neuron or it is metabolised by certain enzymes.

Question 21

What name is given to the process where norepinephrine is taken back into the pre-synaptic neuron?

Answer 21

Re-uptake 1

Question 22

What is the function of the pre-junctional receptor on the pre-synaptic cell of adrenergic neurons?

Answer 22

It detects norepinephrine in the synaptic cleft and provides negative feedback to stop the release of norepinephrine.

Question 23

What are the 2 classes of adrenergic receptors?

Answer 23

Alpha receptors.

Beta receptors.

Question 24

What are the 2 types of alpha receptors?

Answer 24

Alpha-1 receptors.

Alpha-2 receptors.

Question 25

What are the 2 types of beta receptors?

Answer 25

Beta-1 receptors. Beta-2 receptors. Beta-3 receptors.

Question 26

What kind of adrenergic receptors are of no medical significance?

Answer 26

Beta-3 receptors.

Question 27

Where are alpha-1 receptors located?

Answer 27

On the post synaptic membrane of the effector organ.

Question 28

Where are alpha-2 receptors located?

Answer 28

On pre-synaptic nerve endings. On post synaptic neurons of the beta cells of the pancreas and on blood vessels.

Question 29

What happens when alpha-1 receptors are activated in blood vessels?

Answer 29

Vasoconstriction.

Question 30

Alpha-1 receptors are mostly affected by what 3 hormones and in what level of potency?

Answer 30

Epinephrine. Norepinephrine. Isoproterenol.

Question 31

What kind of receptors are alpha-1 receptors?

Answer 31

GCPR’s.

Question 32

What protein are the GCPR's of alpha-1 receptors connected to?

Answer 32

A GQ protein.

Question 33

What happens to the GQ receptor when alpha-1 receptors are activated?

Answer 33

It is activated and the activates phospholipase C which cleaves PIP-3 to form IP-3 and DAG to act as 2nd messengers.

Question 34

What is the function of IP-3 and DAG in alpha-1 receptors?

Answer 34

AG activates a protein kinase. IP-3 releases calcium which activates smooth muscle.

Question 35

Alpha-2 receptors are linked to what protein?

Answer 35

A GI protein.

Question 36

What is the function of the GI protein that is bound to alpha-2 receptors?

Answer 36

It prevents calcium ions being released into the pre-synaptic neuron so no neurotransmitter can be released. It inhibits adenylyl cyclase and this leads to smooth muscle contraction.

Question 37

What protein are beta-1 and beta-2 receptors linked to?

Answer 37

The stimulatory G protein which is GS.

Question 38

What is the function of the GS protein that is bound to beta-1 and beta-2 receptors?

Answer 38

It activates adenylyl cyclase which converts ATP to cyclic AMP.

Question 39

What are the effects on the body once the GS protein that is bound to beta-1 and beta-2 receptors has been activated?

Answer 39

It stimulates heart muscle contraction. It stimulates smooth muscle relaxation. It stimulates glycogenolysis.

Question 40

Where are beta-1 receptors located?

Answer 40

In the heart. In the juxta-glomerular apparatus of the kidney. In fat cells.

Question 41

Will beta-1 receptors have a higher affinity for epinephrine or norepinephrine?

Answer 41

It has equal affinity for both.

Question 42

Increases in heart rate will always be due to what kind of receptors?

Answer 42

Beta-1 receptors.

Question 43

Where are beta-2 receptors located?

Answer 43

In the blood vessels of skeletal muscle. In the liver. In the smooth muscles of the bronchus. In the GI tract. In the uterus.

Question 44

Will beta-2 receptors have a higher affinity for epinephrine or norepinephrine?

Answer 44

Epinephrine.

Question 45

Epinephrine binding to the beta-1 receptors of the heart will have what 3 effects on the heart?

Answer 45

Increased heart rate. Increased contractility of the heart. Increased cardiac output.

Question 46

Norepinephrine binding to the beta-1 receptors of the heart will have what 2 effects on the heart?

Answer 46

Initial increase in heart rate before it is reduced by vagal stimulation. Increased contractility of the heart.

Question 47

Epinephrine binding to the beta-1 receptors of the heart will have what 2 effects on blood pressure?

Answer 47

Increase in systolic pressure. Decrease in diastolic pressure.

Question 48

Norepinephrine binding to the beta-1 receptors of the heart will have what 2 effects on blood pressure?

Answer 48

Increase in systolic pressure. Increase in diastolic pressure.

Question 49

What receptors are found in the blood vessels of the skin, the mucosa and the kidneys?

Answer 49

Alpha-1 receptors. Alpha-2 receptors.

Question 50

Epinephrine binding to the alpha-1 receptors and alpha-2 receptors of the blood vessels will have what effects on blood vessel size?

Answer 50

Vasoconstriction.

Question 51

Norepinephrine binding to the alpha-1 receptors and alpha-2 receptors of the blood vessels will have what effects on blood vessel size?

Answer 51

Vasoconstriction.

Question 52

What receptors are found in the blood vessels of the splanchnic organs and heart?

Answer 52

Alpha receptors. Beta-2 receptors.

Question 53

Epinephrine binding to the alpha receptors and beta-2 receptors of the blood vessels will have what effects on blood vessel size?

Answer 53

Vasodilation.

Question 54

Are the compensatory changes to the heart rate following the release of epinephrine?

Answer 54

No, the heart will continue to beat at a high rate.

Question 55

What adrenergic receptors are found in the bronchial muscle?

Answer 55

Beta-2 receptors.

Question 56

What effect will epinephrine have on the beta-2 receptors of the bronchial muscle?

Answer 56

Relaxation of the muscle.

Question 57

What adrenergic receptors are found in the smooth muscle of the GIT?

Answer 57

Alpha-1 receptors. Alpha-2 receptors. Beta-2 receptors.

Question 58

What effect will epinephrine have on the receptors that control the smooth muscle of the GIT?

Answer 58

Relaxation of the muscles.

Question 59

What effect will norepinephrine have on the receptors that control the smooth muscle of the GIT?

Answer 59

Relaxation of the muscles.

Question 60

What receptors are found on the detrusor muscle of the bladder?

Answer 60

Beta-2 receptors.

Question 61

What receptors are found on the sphincter muscle of the bladder?

Answer 61

Alpha-1 receptor.

Question 62

What effect will epinephrine have when it binds to the detrusor muscle of the bladder?

Answer 62

Relaxation.

Question 63

What effect will epinephrine have when it binds to the sphincter of the bladder?

Answer 63

Contraction.

Question 64

What effect will norepinephrine have when it binds to the sphincter of the bladder?

Answer 64

Contraction.

Question 65

What adrenergic receptors are found on the uterus?

Answer 65

Alpha-1 receptors. Alpha-2 receptors. Beta-2 receptors.

Question 66

What effect will epinephrine have when it binds to the adrenergic receptors of the uterus?

Answer 66

Relaxation/contraction of the uterus.

Question 67

What adrenergic receptors are found on the vas deferens of the male?

Answer 67

Alpha-1 receptors.

Question 68

What effect will epinephrine have when it binds to the adrenergic receptors of the vas deferens of the male?

Answer 68

Ejaculation.

Question 69

What effect will norepinephrine have when it binds to the adrenergic receptors of the vas deferens of the male?

Answer 69

Ejaculation.

Question 70

What adrenergic receptors are found on the pilomotor muscles of the skin?

Answer 70

Alpha-1 receptors.

Question 71

What effects will norepinephrine have on the adrenergic receptors of the pilomotor muscles of the skin?

Answer 71

Contraction.

Question 72

What effects will epinephrine have on the adrenergic receptors of the pilomotor muscles of the skin?

Answer 72

Contraction.

Question 73

What adrenergic receptors are found on the radial muscle of the iris?

Answer 73

Alpha-1 receptors.

Question 74

What effects will norepinephrine have on the adrenergic receptors of the radial muscle of the iris?

Answer 74

Contraction/pupil dilation.

Question 75

What effects will epinephrine have on the adrenergic receptors of the radial muscle of the iris?

Answer 75

Contraction/pupil dilation.

Question 76

What adrenergic receptors are found on the ciliary muscles of the eye?

Answer 76

Beta-2 receptors.

Question 77

What effects will epinephrine have on the adrenergic receptors of the ciliary muscles of the eye?

Answer 77

Relaxation.

Question 78

What effects will norepinephrine/epinephrine have when it binds to beta-2 and alpha-1 receptors of the liver?

Answer 78

Glycogenolysis.

Question 79

What effects will norepinephrine/epinephrine have when it binds to alpha-2 and beta-2 receptors on the beta cells of the pancreas?

Answer 79

Alpha-2 receptors lead to decreased secretion. Beta-2 receptors lead to increased secretion.

Question 80

What are the major functions of alpha-1 receptors?

Answer 80

Vasoconstriction of blood vessels. Increasing the muscle tone in sphincter muscles.

Question 81

What is the major function of alpha-2 receptors?

Answer 81

Vasoconstriction of blood vessels.

Question 82

What is the major function of beta-1 receptors?

Answer 82

An increase in cardiac output. Vasodilation within skeletal muscle.

Question 83

What is the major function of beta-2 receptors?

Answer 83

Relaxation of smooth muscle in certain areas of the body. Glycogenolysis.

Question 84

Are catecholamines well absorbed via the oral route?

Answer 84

No.

Question 85

Are catecholamines well absorbed via the subcutanous route?

Answer 85

Yes, but they are absorbed very slowly.

Question 86

What enzymes will metabolise catecholamines?

Answer 86

Mono-amine oxidase. Catechol-O-methyltransferase.

Question 87

How are catecholamines excreted?

Answer 87

In urine.