Sympathetic Pharmacology

Question 1

State the different types of adrenoreceptors

Answer 1

Alpha 1, alpha 2, beta 1 and beta 2

Question 2

Give the location, effect and endogenous ligand of alpha 1

Answer 2

Alpha 1 are found on smooth muscle, bladder, blood vessels and anal sphincter
They cause contraction via the release of adrenaline

Question 3

Give the location, effect and endogenous ligand of alpha 2

Answer 3

Alpha 2 are found in the sympathetic nerve varicosities (where they inhibit noradrenaline release) and central nervous system (where they inhibit sympathetic nervous system)
Ligand is noradrenaline

Question 4

Give the location,effect and endogenous ligand of beta 1

Answer 4

Beta 1 are found in the heart where they increase heart rate, conduction velocity and contractility via the release of noradrenaline

Question 5

Give the location, effect and endogenous ligand of beta 2

Answer 5

Beta 2 are found in bronchial smooth muscles and SM of arteries and veins

Question 6

Give examples of alpha-adrenoceptor agonists

Answer 6

Naphazoline, xylometazoline, oxymetazoline

Question 7

Give an example of an alpha-adrenoceptor antagonist

Answer 7

Phentolamine

Question 8

Example of beta adrenoceptor agonist

Answer 8

Isoprenaline

Question 9

Example of beta adrenoceptor antagonist

Answer 9

Propranolol, timolol, oxyprenolol

Question 10

What are the selective alpha 1 agonists?

Answer 10

Phenylephrine, methoxamine, metaraminol

Question 11

What are selective alpha 1 antagonists?

Answer 11

Tamsulosin, prazosin, doxazosin

Question 12

What are selective alpha 2 agonists?

Answer 12

Clonidine, dexmedetomedine, brimonidine, lofexidine

Question 13

What are beta 1 selective agonist?

Answer 13

Dobutamine

Question 14

What are beta 1 selective antagonists?

Answer 14

Atenolol, bisoprolol

Question 15

What re beta 2 selective agonists?

Answer 15

Salbutamol, salmeterol

Question 16

State the therapeutic uses of directly acting sympathomimetics

Answer 16

Cardiac arrest
Sepsis
Anaphylactic shock

Question 17

How does agonist act at beta 2 adrenoceptor?

Answer 17

Binds to GPCR to cause increase adenylate cyclase, increase cAMP levels which ultimately lead to bronchodilatation.

Question 18

Give examples and explain mechanism of action of indirectly acting sympathomimetics

Answer 18

Tricyclic antidepressant (clomipramine, imipramine, amitriptyline and reboxetine)
They enhance the function of NA and 5-HT in brain (and NA in varicosities) by blocking their reuptake

Question 19

What is the effect of cocaine and amphetamine on CNS?

Answer 19

Stimulates it by preventing neuronal reuptake of NA to heighten sympathetic excitation
Also inhibit DA uptake
Amphetamine are taken up via neuronal uptake and causes exocytotic NA

Question 20

What are adrenoceptor antagonists used for?

Answer 20

IHD, reduce cardiac load during heart beat

Question 21

When are beta blockers contraindicated?

Answer 21

Asthmatic patients

Question 22

What are alpha adrenoceptor antagonists used for?

Answer 22

Hypertension
Side effect: postural hypotension as it decreases reflex of vasoconstriction that occurs a when standing up
Benign prostatic hypertrophic