Drug Receptors Flashcards Preview

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Flashcards in Drug Receptors Deck (43):
1

Bind substances called ligands (drugs or endogenous substances)

Receptors

2

Anticancer drugs; blocks normal metabolic pathways in the body

Antimetabolites

3

Pharmacological doses of vitamins; supplementing normal metabolized substances

Metabolites

4

Chemical reactions; a basic substance that reduces acidity

Antacids

5

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

Chelating Agents

6

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

receptor

7

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

Extracellular

8

These type of receptors usually bind ligands that are water soluble

Cell surface receptors

9

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

Intracellular receptors

10

The _____ component of the cell surface receptor mediates the action

Intracellular

11

Name 3 different linked cell membrane receptors

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

12

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

Ion channel

13

Receptor at the neuromuscular junction

Nicotinic

14

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

Enzyme

15

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

G-protein

16

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

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

17

What are the ligands for intracellular receptors and their characteristics?

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

18

Measure of attraction between drug and receptor

Affinity

19

Low concentration of drug needed to bind to unoccupied receptors

High affinity

20

High drug concentration needed to bind to low unoccupied receptors

Low affinity

21

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

Selective

22

How specific a drug is for one type of receptor

Drug selectivity

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

Dose-response

24

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

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

25

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

Agonist

26

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

Antagonist

27

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

Competitive Antagonist

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

Noncompetitive Antagonist

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

Partial agonists

30

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

Decreased; decrease

31

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

Increased; increase

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

Desnesitization

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

Receptor down-regulation

34

Desensitization and down-regulation are examples of ______ feedback system

Negative

35

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

Down-regulation

36

Two responses to decreased activation of receptors

1. Supersensitivity
2. Receptor up-regulation

37

Increase in sensitivity of receptors; fairly rapid and transient response

Supersensitivity

38

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

Receptor up-regulation

39

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

Denervation

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

Fibrillations

41

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

increases; first

42

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

Over the whole surface; second

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

True; such as with beta-blockers