Receptor Classes, Structures, Signaling Mechanisms, and Drug Examples

Question 1

Ligand-gated ion channel receptors

Answer 1

• Nicotinic acetylcholine receptor
• plasma membrane
• 5 subunits
• 4 transmembrane domains each

Question 2

Ligand-gated ion channel receptors

Answer 2

Agonist binding to extracellular domain opens transmembrane ion pore allowing Na+ ions to enter cell

Question 3

G protein-coupled receptors

Answer 3

• B2-adrenergic receptor for epinephrine, norepinephrine
• in plasma membrane
• 7 transmembrane domains

Question 4

G protein-coupled receptors

Answer 4

agonists binding inside the transmembrane domains activates associated GTP-binding proteins that in turn regulate effector enzymes that generate intracellular second messenger molecules

Question 5

G protein-coupled receptors

Answer 5

Targets for OVER HALF OF ALL PRESCRIPTIONS

Question 6

Receptors with intrinsic enzyme activity

Answer 6

• insulin receptor
• cell surface
  2 single-transmembrane proteins

Question 7

Receptors with intrinsic enzyme activity

Answer 7

agonist binding to extracellular domain activates enzymatic activity of intracellular domain

Question 8

Receptors with intrinsic enzyme activity

Answer 8

• most commonly tyrosine kinase activity
• phosphorylated substrates then medicate effects
• “tyrosine kinase receptors”

Question 9

Receptors with intrinsic enzyme activity

Answer 9

regulate gene expression, cell growth, cancer, differentiation

Question 10

Nuclear transcription factor receptors

Answer 10

• estrogen receptor

- steroid hormone receptors

Question 11

Nuclear transcription factor receptors

Answer 11

agonist binds to ligand binding domain, allows DNA binding domain to bind specific DNA sequences, activation domain then increases/decreases transcription of associated genes

Question 12

Nuclear transcription factor receptors

Answer 12

regulate gene expression, cell growth, cancer, development