Sympathomimetics

Question 1

Drugs with sympathomimetic activity will be

Answer 1

interacting with GPCrs metaboprotpic

Question 2

All adrenergic receptors are

Answer 2

GPCRs (alpha and beta) (metaboptropic)

Question 3

Two main types of

Answer 3

alpha

Question 4

three main types of

Answer 4

beta

Question 5

Alpha 1 is associated with

Answer 5

Gq which activates phospholipase C and cleaves DAG and IP3 which both function as secondary messengers.

Question 6

All beta receptors are associated with

Answer 6

Gs G proteins

Question 7

Gs proteins are associated with

Answer 7

Adenyl cyclase the increased cAMP, then further activation into the cell.

Question 8

Alpha 2 is associated with

Answer 8

Gi- which are associated with Adenyl Cylase, but they actually block Adenyl cyclase.

So, a lot of alpha 2 receptors will be expressed presynaptically and activation of these recptors will be inhibitory and block a lot of things.

Question 9

Alpha 2 is less common in

Answer 9

periphery , but can be found in the CNS.

Question 10

Phenylephrine and methoxamine

Answer 10

(alpha agonist ) a1>a2»»»»»B (almost none to beta)

Question 11

Norepinephrine

Answer 11

(mixed) a1=a2; B1»B2

Question 12

Epinephrine

Answer 12

(mixed)a1=a2; B1=B2 this activates all alphas and all betas and is why can be a lifesaving drug. Released from adrenal medulla so it gets distributed in the entire system and effects all its receptors.

Question 13

Dobutamide

Answer 13

B1>B2»»>a this is a beta agonist

Question 14

Isoproterenol

Answer 14

B1=B2»»>a (beta agonist )

Question 15

Albuterol, terbutaline, metaproterenol

Answer 15

B2»»B1»»>a (beta agonist) mostly beta 2

Question 16

Dopamine

Answer 16

D1=D2»B»a (dopamine agonist )

Question 17

Fenoldopam

Answer 17

D1»D2 (dopamine agonist)

Question 18

If treating a condition that is specific to beta , you want to be more

Answer 18

selective

Question 19

Catchcholamines with two hydroxyl groups on the molecule

Answer 19

norepinephrine

epinephrine

isoproterenol

dopamine

“DINE”

won’t have CNS effects because they are polar

Question 20

Noncatecholamines sympathomimetics

Answer 20

phenylephrine

ephedrine

amphetamine

metamphetamine

these do have CNS effects

“MEAP”

Question 21

What effects do noncatecholamines sympathomimetics have on the periphery?

Answer 21

increase BP

increase heart contractions

increase risk of MI

does this because it affects receptors on the periphery.

Question 22

Alpha 1 effects which organs

Answer 22

Most vascular smooth muscle (innervated)

Pupillary dilator muscle (contraction dilated pupils)

Pilomotor smooth muscle (hair)

Prostate (contraction)

Heart (increase force of contraction)

Question 23

Beta 1 effects

Answer 23

heart, juxtaglomerular cells (increases force and rate of contraction; increases renin release)

Question 24

Beta 2 effects

Answer 24

Respiratory, uterine, and vascular smooth muscle (promotes smooth muscle relaxation)

Skeletal muscle (promotes potassium uptake)

Human liver (activates glycogenolysis)

Question 25

Beta 3 effects

Answer 25

bladder ( relaxes detrusor muscle)

fat cells (activates lipolysis)

Question 26

D1 effects

Answer 26

smooth muscle (dilates renal blood vessels)

Question 27

D2 effects

Answer 27

nerve endings (modulates transmitter release)

Question 28

These receptors are extremely highly expressed in the heart

Answer 28

Beta 1

Question 29

So, if epi /ephidrine is used, it will activate all receptors and cause contraction

Answer 29

this is desired with anaphylaxis

Question 30

Nasal spray contains

Answer 30

alpha 1 agonist which causes vasoconstriction

same principle is used to stop eye watering

Question 31

Alpha one agonist can

Answer 31

raise BP

Question 32

Nasal sprays are contraindicated in patients with

Answer 32

high blood pressure because they contain alpha 1 agonist which can raise blood pressure even more

Question 33

Alpha 1 decongestants are prohibited with prostate hyperplasia, why?

Answer 33

Because they cause contraction of the prostate gland which can squeeze the urethra and cause problems.

Question 34

Activation of Beta 1 ?

Answer 34

causes increase force and rate of contraction.

If force and rate increases then it requires more oxygen which could lead to MI in patients with atherosclerosis

Question 35

Isoproterenol activates ?

Answer 35

B1=B2 and is used to induce MI in model organisms because it increases the force of contraction requiring the heart to need more oxygen which leads to MI, so B1 agonist is not used very often.

Question 36

Beta 2 receptors are very common in

Answer 36

respiratory tract, uterus, and vascular and smooth muscles

Drugs that activate B2 promote smooth muscle relaxation which is desired in the respiratory tract.

Question 37

B2 agonist are used to treat

Answer 37

Asthma because they instantly open up the airway by activating B2 receptors. Also sometimes used to stop premature labor.

Question 38

When treating asthma, you want to be sure that the drug is very

Answer 38

selective for B2 because you do not want to activate B1, otherwise you would increase BP and increase cardiac demand.

It is almost not possible to be this selective, so B2 agonist are contraindicated in patients with HTN or remarkable cardiac history such as (MI)

So, how do we treat these patients with asthma?

We go on the fact that apart from adrenergic receptors, we also have muscarinic receptors in our airways, so instead of a B2 agonist, we could use cholinolytics because these will cause bronchodilation whereas cholinomimetics will induce bronchoconstriction.