Drug receptor interactions

Question 1

Pharmacodynamics basics

Answer 1

Drugs are molecules Drugs act at a molecular level (tend to act on receptor molecules)

Question 2

Drugs acting on receptor

Answer 2

Receptor is like the keyhole and the drug is the key *Epinephrine acts on receptor and turns on a cellular action Drugs can mimic this action

Question 3

Agonists

Answer 3

Drugs that ACTIVATE the receptor

Question 4

Antagonists

Answer 4

Drugs that BLOCK the receptor, preventing natural substance from acting

Question 5

Enzymes as receptors

Answer 5

Sometimes the receptor is an enzyme Drug blocks its action which interferes with creation of the product

Question 6

Most common types of receptors

Answer 6

Membrane-bound Drug interacting with a cellular protein Drug and enzyme Drug and ion channels

Question 7

Membrane-bound receptors

Answer 7

Receive drugs, trigger internal process

Question 8

Drug interacting w/cellular protein

Answer 8

Drug enters the cell and interacts with an internal protein **Usually go to the nucleus

Question 9

Drug-enzyme

Answer 9

Drug interferes with enzyme, altering production of a product

Question 10

Drug and ion channels

Answer 10

Drug blocks or opens ion channel

Question 11

The other 1% of drugs that do NOT act on cellular receptors

Answer 11

Osmotics Antacids Chelating agents (bind to toxins) Other compounds that bind (cholesterol binding agents)

Question 12

Steps to drug action: Agonists

Answer 12

1. Drug binds receptor 2. Receptor initiates cellular process 3. Group of cells have a tissue effect 4. Tissue effects leads to physiological effect 5. Body may respond with compensatory effect

Question 13

Examples of agonist action (BV= blood vessel) (BP= blood pressure)

Answer 13

1. Drug binds receptor 2. Releasing of calcium= mm fibre contraction 3. Sm mm contraction=BV constriction 4. BV constriction= higher BP 5. Raised BP= reflex bradycardia

Question 14

Binding of agonists

Answer 14

reversible: degree of binding depends on local drug concentration more drug=more effect

Question 15

Binding of antagonists: reversible

Answer 15

MAY be reversible: degree of local drug concentration=degree of effect

Question 16

Binding of antagonists: irreversible

Answer 16

Knocks out the receptor Local drug concentration does NOT need to be maintained to continue effect

Question 17

Action of an agonist and antagonists at a G protein receptor

Answer 17

Agonist fits into receptor, changes receptor conformation to activate G protein (think dirty here, take off the underwear, change the conformation) An ANTAGONIST fits in the receptor, does not have an effect and blocks the agonist’s access (cock-block’s agonist)