Drug Receptors

Question 1

Bind substances called ligands (drugs or endogenous substances)

Answer 1

Receptors

Question 2

Anticancer drugs; blocks normal metabolic pathways in the body

Answer 2

Antimetabolites

Question 3

Pharmacological doses of vitamins; supplementing normal metabolized substances

Answer 3

Metabolites

Question 4

Chemical reactions; a basic substance that reduces acidity

Answer 4

Antacids

Question 5

Binds to heavy metals to prevent them from interacting with the body

Answer 5

Chelating Agents

Question 6

Component that binds the drug and determines the action of the drug or endogenous compound

Answer 6

receptor

Question 7

The _______ component of the cell surface receptor binds drug or endogenous compound

Answer 7

Extracellular

Question 8

These type of receptors usually bind ligands that are water soluble

Answer 8

Cell surface receptors

Question 9

These type of receptors bind ligands that are able to pass through the lipid-bilyare cell membrane

Answer 9

Intracellular receptors

Question 10

The _____ component of the cell surface receptor mediates the action

Answer 10

Intracellular

Question 11

Name 3 different linked cell membrane receptors

Answer 11

1. Ion channels
2. Enzymes
3. Regulatory G-proteins

Question 12

________-linked receptors are ion channels; ligand binding can open (or close) the ion channel and depolarize or polarize the cell membrane

Answer 12

Ion channel

Question 13

Receptor at the neuromuscular junction

Answer 13

Nicotinic

Question 14

_______-linked receptors where the binding of ligand to extracellular domain activates the enzyme component of the receptor

Answer 14

Enzyme

Question 15

_______- linked receptors affect cells through intermediate regulatory proteins; these regulatory proteins are activated by binding to guanine nucleotides

Answer 15

G-protein

Question 16

What are 4 common causes in alterations in the G-protein in its synthesis and function?

Answer 16

1. Alcoholism
2. Diabetes mellitus
3. Heart failure
4. Certain tumors

Question 17

What are the ligands for intracellular receptors and their characteristics?

Answer 17

steroids and steroid-like substances; small, hydrophobic and lipophilic

Question 18

Measure of attraction between drug and receptor

Answer 18

Affinity

Question 19

Low concentration of drug needed to bind to unoccupied receptors

Answer 19

High affinity

Question 20

High drug concentration needed to bind to low unoccupied receptors

Answer 20

Low affinity

Question 21

A drug affects only one type of cell or tissue and produces a specific physiological response

Answer 21

Selective

Question 22

How specific a drug is for one type of receptor

Answer 22

Drug selectivity

Question 23

____________ curve related to the number of receptors which have bound the drug; percent is related to percent occupancy of receptors but is not an absolute correlation

Answer 23

Dose-response

Question 24

The ability of a drug to have an effect on a cell

Answer 24

Efficacy

Remember: efficacy does NOT necessarily relate to the affinity of a drug

Question 25

Binds to a receptor and has an effect; has affinity; has efficacy

Answer 25

Agonist

Question 26

Binds to a receptor and does not have an effect; blocks effects of normal chemicals; has affinity; does not have efficacy

Answer 26

Antagonist

Question 27

Bind to the same site on the receptor as the agonist, but have no efficacy

Answer 27

Competitive Antagonist

Question 28

Bind to the receptor at a site other than where the agonist binds; binds to a receptor and stays bound, which essentially inactivates the receptor; long-lasting effects

Answer 28

Noncompetitive Antagonist

Question 29

Act as agonists, but do not produce a maximal response, even if all receptors are binding the drug; appear to bind but not to fully activate the receptor

Answer 29

Partial agonists

Question 30

Increased receptor stimulation by agonists can result in (increased/decreased) sensitivity or a (increase/decrease) in receptor numbers

Answer 30

Decreased; decrease

Question 31

Decreased receptor stimulation [lack of agonist or treatment with antagonist] can result in (increased/decreased) sensitivity or a (increase/decrease) in receptor numbers

Answer 31

Increased; increase

Question 32

The response to overstimulation of receptors; due to prolonged stimulation of receptors by agonist or chemical modification of receptor proteins; return to normal state may occur within minutes after agonist is removed

Answer 32

Desnesitization

Question 33

Slower, more prolonged response compared to desensitization; number of receptors is decreased due to increased receptor removal or decreased receptor synthesis; can last several days

Answer 33

Receptor down-regulation

Question 34

Desensitization and down-regulation are examples of ______ feedback system

Answer 34

Negative

Question 35

________ may be the mechanism for the action of several drug categories such as antidepressants

Answer 35

Down-regulation

Question 36

Two responses to decreased activation of receptors

Answer 36

1. Supersensitivity | 2. Receptor up-regulation

Question 37

Increase in sensitivity of receptors; fairly rapid and transient response

Answer 37

Supersensitivity

Question 38

Slower and longer lasting increase in number of receptors; making new receptors

Answer 38

Receptor up-regulation

Question 39

In peripheral nervous system when a nerve is severed; a reversible condition where axons can grow back and NMJ is formed

Answer 39

Denervation

Question 40

When individual muscle fibers spontaneously depolarize and contract in a non-coordinated function due to loss of innervation to those muscle cells; happens in polio as well

Answer 40

Fibrillations

Question 41

When a nerve is severed, the total number of ACh receptors on the muscle fiber _______; this happens _____ in denervation

Answer 41

increases; first

Question 42

In a denerved muscle fiber, ACh receptors are found __________; this happens ______ in denervation

Answer 42

Over the whole surface; second

Question 43

True or false: Similar changes that occur in the end plate of the NMJ that has been denerved also happens with long-term antagonist treatment

Answer 43

True; such as with beta-blockers