Receptors/Ligands/CNS

Question 1

antagonistic cathecholamine

Answer 1

Beta adrenergic blocker

Question 2

what kind of receptor is α1 ?

Answer 2

G_q

activates phospholipase C (PLC)

second messenger: IP₃ and DAG

effect: elevated PKC and free Ca⁺⁺

Question 3

Syntetic agonist cathecholamine

Answer 3

Isoprotenerol (Isuprel, Medihaler-Iso)

Dobutamine

Question 4

what are the main areas where you can find serotonin receptors

Answer 4

wall of interstine

blood

CNS

Question 5

alpha 1 (α1) activation

Answer 5

• peripheral blood vessels (smooth muscle) → vasoconstriction
• heart → increased force of contraction (synergistic wih Beta 1)
• gut → relaxation of muscles
• sphincters (smooth muscle) → contraction
• bronchi (smooth muscle)→ contraction
• iris (radial mucle)→ contraction → mydriasis (dilation of pupil)
• prostate and uterus → contraction
• pancreas → decrease insulin secretion (opposite of beta 2)

Question 6

activation of dopaminergic 2 receptors

Answer 6

presynaptic:

• inhibition of NE release
• nausea and vomiting (affecting the stomach, nucleus tractus solitarus, chemoreceptor trigger zone)

postsynaptic:

• constriction
  
  • stomach contraction = vomiting

Question 7

what serotonin receptors do we target pharmacologically?

Answer 7

the CNS ones

Question 8

ß receptor cathecholamine affinity

Answer 8

isoprotenerol > epi > norepi

(ß2 - no response to norepi)

Question 9

which receptor does not react to neorepinephrine?

Answer 9

Beta 2 receptor

Question 10

postsynaptic α2 receptor activation

Answer 10

• coronaries → constriction
• CNS → sedation and analgesia (via decreased SNS outflow from brainstem)
• platelets → aggregation

Question 11

what kind of receptor is α2 ?

Answer 11

G_i

inactivates adenyl cyclase

decreases cAMP and increases K⁺ conductivity

Question 12

what kind of organic compounds are cathecholamines?

Answer 12

mono-amines

has catechol - a benzene with 2 hyroxyl side groups

Question 13

where do you find dopaminergic 1 receptors?

Answer 13

postsynaptic in:

• renal smooth muscle
• mesenteric smooth muscle
• splenic smooth muscle
• coronary vessel smooth muscle
• cerebral blood vessels

Question 14

presynaptic α2 receptor activation

Answer 14

• peripheral vascular smooth muscle → vasodilation (if you inhibit the inhibition of adenyl cyclase you end up with more cAMP)
• coronaries→ vasodilation
• adrenergic and cholinergic nerve terminals → inhibits NE release → inhibits sympathetic outflow → decerased BP and HR
• inhibits CNS activity
• GI tract→ relaxation

Question 15

α receptor cathecholamine affinity

Answer 15

norepi > epi > isoprotenerol

Question 16

who makes catecholamines?

Answer 16

neurons and adrenal gland

Question 17

what type of receptor is dopaminergic 1 receptor?

Answer 17

G_s

activates adenyl cyclase

increased cAMP

Question 18

what type of receptor is dopaminergic 2 receptor?

Answer 18

G_i

inhibits adenyl cyclase

decreased cAMP

Question 19

natural agonist cathecolamines

Answer 19

Epi

Norepi

Dopamine

Question 20

What kind of receptor is the serotonin receptor?

Answer 20

5-hydroxytryptamine receptors or 5-HT receptors

there are at least 14 subtypes - different kinds of receptors, different functiomn, all over the body

some are GPCR and some are ligand-gated ion channels

Question 21

where do you find dopaminergic 2 receptors?

Answer 21

presynaptic

• nerve endings
• CNS (nucleus tractus solitarus, chemoreceptor trigger zone)

postsynaptic

• smooth muscle

Question 22

beta 2 activation

Answer 22

1. bronchial (smooth muscle) → bronchodilation
2. vascular (visceral smooth muscle) → vasodilation
3. GI, GU (visceral smooth muscle) → decreased motility, delayed digestion, contract sphincters
4. uterine (visceral smooth muscle) → relaxation (inhibits labor)
5. skin (smooth muscle)
6. mast cells → decreased histamine release
7. myocardium → increased atrial contractility, increased HR (but less than ß1)
8. coronaries → vasodilation
9. kidneys → delay micturition; release renin
10. skeletal muscle → vasodilation and increased K⁺ uptake
11. liver → glycogenolysis and gluconeogenesis
12. pancreas → increased insulin secretion
13. adrenergic terminal → increased release of NE

Question 23

activation of dopaminergic 1 receptors

Answer 23

vasodilation

• renal smooth muscle
• mesenteric smooth muscle
• splenic smooth muscle
• coronary vessel smooth muscle
• cerebral blood vessels

Question 24

where do you find beta 2 receptors?

Answer 24

1. bronchial (smooth muscle)
2. vascular (visceral smooth muscle)
3. GI, GU (visceral smooth muscle)
4. uterine (visceral smooth muscle)
5. skin (smooth muscle)
6. mast cells
7. myocardium
8. coronaries
9. kidneys
10. skeletal muscle
11. liver
12. pancreas
13. adrenergic terminal

Question 25

where is α1 found?

Answer 25

Postsynaptic in * peripheral blood vessels (smooth muscle) * heart * gut - sphincters (smooth muscle) * glands * bronchi (smooth muscle) * iris (radial mucle) * prostate and uterus * pancreas

Question 26

dopamine receptor affinity?

Answer 26

dopamine ONLY )no other catecholamines)

Question 27

what kind of receptors are beta 1 receptors?

Answer 27

G_s activation of adenyl cyclase increased cAMP

Question 28

what kind of receptors are beta 2 receptors?

Answer 28

Gs activation of adenyl cyclase increased cAMP

Question 29

where do you find beta 1 receptors?

Answer 29

* myocardium * SN node * ventricular conduction system * coronaries * kidneys

Question 30

where is postsynaptic α2 receptor found?

Answer 30

* coronaries * CNS * platelets

Question 31

beta 1 activation

Answer 31

* myocardium → increased **inotropy** * SN node → increased **chronotropy** * ventricular conduction system → increased **conduction velocity** * coronaries → **relaxation** * kidneys → **renin release**

Question 32

where is presynaptic α2 receptor found?

Answer 32

* peripheral vascular smooth muscle * coronaries * brain (especially in brainstem - adrenergic and cholinergic nerve terminals) * GI tract