SCT II - Circulation Adrenergic Receptors

Question 1

What are the types of adrenergic receptors and what neurotransmitters do they prefer?

Answer 1

α: Norepi > Epi
β: Epi > Norepi

Question 2

Name the types of adrenergic alpha receptors and what G-coupled protein they use

Answer 2

α-1: Gq
α-2: Gi

Question 3

Name the types of adrenergic beta receptors and what G-coupled protein they use

Answer 3

β-1: Gs
β-2: Gs
β-3: Gs

Question 4

β-1 Receptor

G-Protein? Location? Agonists? Antagonists?

Answer 4

Gs protein: [cAMP]i INCREASES
Location: Heart - Positive tropic effect

Agonists: Isoproterenol, Adrenaline
Antagonists: -lol (Propranolol, Pindolol)

Question 5

β-2 Receptor

G-Protein? Location? Agonists? Antagonists?

Answer 5

Gs protein: [cAMP]i INCREASES
Location: Smooth muscle (airways, arterioles of skeletal muscle, coronaries, bladders) - RELAXATION

Agonists: Isoproterenol, Adrenaline, Salbutamol (Albuterol)
Antagonists: Propranolol

BRONCHODILATION & VASODILATION

Question 6

β-3 Receptor

G-Protein? Location? Agonists? Antagonists?

Answer 6

Gs protein: [cAMP]i INCREASES
Location: Adipose tissue

Question 7

α-1 Receptor

G-Protein? Location? Agonists? Antagonists?

Answer 7

Gq protein: Increasing [Ca2+]
Location: Smooth muscle, increase in calcium causes contraction

Agonists: Noradrenaline, Phenylephrine
Antagonists: Phenoxybenzamine, Phentolamine, Prazosin (Minipress)

Question 8

α-2 Receptor

G-Protein? Location? Agonists? Antagonists?

Answer 8

Gi protein: Inhibition! [cAMP]i DECREASES
Location: Neurons, form of negative feedback, where a neurotransmitter binds to this receptor to inhibit the neuron itself

Agonists: Clonidine, Noradrenaline
Antagonists: Phentolamine, Yohimbine (Aphrodisiac)