Drug Receptors Flashcards

1
Q

Bind substances called ligands (drugs or endogenous substances)

A

Receptors

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2
Q

Anticancer drugs; blocks normal metabolic pathways in the body

A

Antimetabolites

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3
Q

Pharmacological doses of vitamins; supplementing normal metabolized substances

A

Metabolites

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4
Q

Chemical reactions; a basic substance that reduces acidity

A

Antacids

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5
Q

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

A

Chelating Agents

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6
Q

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

A

receptor

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7
Q

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

A

Extracellular

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8
Q

These type of receptors usually bind ligands that are water soluble

A

Cell surface receptors

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9
Q

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

A

Intracellular receptors

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10
Q

The _____ component of the cell surface receptor mediates the action

A

Intracellular

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11
Q

Name 3 different linked cell membrane receptors

A
  1. Ion channels
  2. Enzymes
  3. Regulatory G-proteins
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12
Q

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

A

Ion channel

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13
Q

Receptor at the neuromuscular junction

A

Nicotinic

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14
Q

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

A

Enzyme

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15
Q

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

A

G-protein

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16
Q

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

A
  1. Alcoholism
  2. Diabetes mellitus
  3. Heart failure
  4. Certain tumors
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17
Q

What are the ligands for intracellular receptors and their characteristics?

A

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

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18
Q

Measure of attraction between drug and receptor

19
Q

Low concentration of drug needed to bind to unoccupied receptors

A

High affinity

20
Q

High drug concentration needed to bind to low unoccupied receptors

A

Low affinity

21
Q

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

22
Q

How specific a drug is for one type of receptor

A

Drug selectivity

23
Q

____________ 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

A

Dose-response

24
Q

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

A

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