Agonists And Antagonists

Question 1

What is a agonist?

Answer 1

Thet are molecules capable of inducing a physiological response when binding to a receptor.

Question 2

Agonists are classified according to their _________ and their __________.

Answer 2

Potency and efficacy

Question 3

Full agonists do what?

Answer 3

Elicit a full response equivalent to the endogenous agonist. (100% response)

Question 4

Partial agonist do what

Answer 4

elicit partial response (<100%)

Question 5

What do inverse agonists do?

Answer 5

have intrinsic activity but elicit a response opposite response to that of an agonist.

Question 6

What is a dose response curve?

Answer 6

is typically a plot of log[dose] vs the biological response.

Question 7

The magnitude of the maximum response is termed the ________ and the ED50 is termed the __________.

Answer 7

efficacy, potency

Question 8

Agonists are identified by?

Answer 8

exposing a cell or tissue to the drug then measuring a response.

Question 9

Agonist conc. Is plotted on the ________ of a dose/response curve with the magnitude of the measured response plotted on the _______

Answer 9

X axis and y axis

Question 10

administration of an antagonist by itself will elicit __________

Answer 10

No response

Question 11

Antagonists act by?

Answer 11

altering the effect of a co-administered or endogneous agonist

Question 12

Antagonists inhibit the response produced by an agonist.

TRUE OR FALSE

Answer 12

TRUE

Question 13

To assay for antagonist potency, typically the ________ concentration is held constant and the _________ concentration is slowly increased to inhibit the stimulating effect of the agonist

Answer 13

Agonist, antagonist

Question 14

To analyze this data, the concentration of the antagonist is plotted on the x-axis and the fractional response remaining is plotted on the y - axis. This creates an ?

Answer 14

Inhibition curve

Question 15

IN A INHIBITION CURVE. Instead of an ED50, an IC50, or the concentration required to inhibit the agonist response, is measured as an indication of antagonist potency

Answer 15

TRUE

Question 16

A competitive antagonist does what?

Answer 16

blocks activity of an agonist by binding to the same exact site as the agonist.

Question 17

A non- competitive antagonist does what?

Answer 17

binds to a binding site other than the one that binds the agonist.

Question 18

Typically a _________________________ will produce an apparent decrease in the Emax (maximum elicited response or the asymptote of the dose /response curve

Answer 18

Competitive antagonist

Question 19

Agonists produce an effect when binding to a receptor by stimulating a ______________________?

Answer 19

signal transduction pathway

Question 20

The signal transduction pathway includes conformational changes in the receptor that then produce secondary effects such as______________?

Answer 20

binding of other proteins, activation of enzymes, ion channel conductance and self modification (for example autophosphorylation) among many others

Question 21

The range of ultimate effects is dictated by the?

Answer 21

receptor activated, the metabolism of the cell stimulated, competing signals from other receptors and the number and subtype of the many receptors in the cell.

Question 22

__________ typically replicate the action of the endogenous agonist while _______________ typically block these effects.

Answer 22

Agonists and antagonists

Question 23

Intrinsic activity

Answer 23

Intrinsic activity is the ability of a drug to induce an effect. It is an inherent ability based on the result of a drug binding to a receptor. If the drug can activate the receptor, it is said to have “intrinsic activity”. A drug with intrinsic activity is generally termed an agonist, while a drug that binds to a receptor with no intrinsic activity is called an antagonist.

Question 24

Intrinsic efficacy

Answer 24

While the ability of a drug to elicit a response at a receptor is called “intrinsic activity”, the ability of a drug to elicit a specific amplitude of a response is called “intrinsic efficacy”. The efficacy of a drug is the magnitude of the response it produces; hence, intrinsic efficacy is the ability of a specific receptor/drug interaction to elicit a specific magnitude of response. A drug that elicits the maximum possible response is called a full agonist, while a drug that elicits a smaller response is known as a partial agonist.

Question 25

Structure activity relationship

Answer 25

The relationship between the structure of the drug and its ability to produce a physiological effect.