Kaplan Chapter 2

Question 1

How do pharmacologic antagonists work on receptors?

Answer 1

they work on same receptor

Question 2

How do physiologic antagonists work on receptors?

Answer 2

different receptors

2 agonists with opposing action antagonize each other

Question 3

How do chemical antagonists work on receptors?

Answer 3

They form a complex between effector drug and another compound; no receptor involved

Question 4

How does potentiation of a drug work?

Answer 4

They increase the potency of another drug

Question 5

Formula for TI (therapeutic index).

Answer 5

TI = TD50/ED50

(TD stands for toxic dose)

Question 6

What are some things that act as intracellular receptors?

Answer 6

thyroid hormones
gonadal steroids
vit D.

Question 7

Gs pathway has what downstream messengers?

Answer 7

AC (adenylyl cyclase)
cAMP (second messenger)
protein kinase A

Question 8

Which receptors work through the Gs pathway?

Answer 8

B1, B2, B3, D1

Question 9

Gi pathway has what downstream messengers?

Answer 9

AC (adenylyl cyclase)
cAMP (second messenger)
protein kinase A

Question 10

Which receptors act through Gi pathway?

Answer 10

the “MAD 2”

muscarinic M2

alpha 2

Dopamine 2

Question 11

The Gq pathway acts through what messengers?

Answer 11

IP3 DAG pathway

Question 12

Describe IP3 DAG pathway?

Answer 12

Phosphlipase C cleaves PIP2 into IP3 and DAG
IP3 releases Ca2+ from SR
DAG activates protein kinase C which causes phosphorylation of tissue specific enzymes

Question 13

Which receptors act through the Gq pathway?

Answer 13

M1
M3
alpha 1

Question 14

Nicotinic receptors are coupled to what types of channels?

Answer 14

directly to ion channels

Question 15

Describe JAK STAT pathway?

Answer 15

transmembrane receptor activates JAK

JAK activates STAT (signal transducers and activators of transcription)

STATs dimerize, dissociate and cross nuclear membranes and modulate gene transcription.

Question 16

cGMP messengers act on what?

Answer 16

vascular smooth muscle to cause vasodilation

Question 17

cGMP is associated with what messengers in its signaling pathway? How does it work to cause vasodilation?

Answer 17

GC
cGMP (second messenger)

then cGMP dephosphorylates myosin light chain preventing interaction with actin and causing vasodilation

Question 18

What molecules act on cGMP pathway? Also what is an example of drug associated with this molecule.

Answer 18

NO (nitric oxide) which activates GC thus increasing cGMP in smooth muscle

i.e nitroglycerin

Question 19

What endogenous compounds increase synthesis of NO?

Answer 19

the vasodilators bradykinin and histamine

Question 20

What are examples of compounds that bind to receptors that function as transmembrane enzymes?

Answer 20

insulin and growth factor

Question 21

How do hormones that act on transmembrane enzymes work?

Answer 21

Membrane-spanning macromolecules with recognition sites for binding of insulin and growth factors located externally and a cytoplasmic domain that usually functions as tyrosine kinase.

Binding of ligand causes conformation change (dimerization) so the tyrosine kinase domain becomes activated

This leads to phosphorylation of tissue specific substrate enzymes

Question 22

Formula for clearance that factors in area under the curve?

Answer 22

Cl= (f x dose)/AUC

Question 23

Formula for clearance that doesn’t factor in AUC?

Answer 23

Cl= amount drug cleared/cleared from plasma

Question 24

Hendersohn-Hasselback equation?

Answer 24

pH= pKa + log ionized conc./unionized concentration

Question 25

What is the formula for clearance when given GFR?

Answer 25

Clearance = ff x GFR