ANTAGONISTS 2

Question 1

WHAT IS THE KD MEASURING

Answer 1

THE BACK REACTION/FORWARD REACTION

Question 2

WHAT RELATIONSHIP DOES THE KD HAVE WITH AFFINITY

Answer 2

INVERSE RELATIONSHIP

THE SMALLER THE KD THE HIGHER THE AFFINITY

Question 3

WHAT IS THE TERM USED TO DESCRIBE THE CONCENTRATION OF DRUG IT TAKES TO OCCUPY 50% OF RECEPTORS

Answer 3

KD

Question 4

WHY DO WE MEASURE RECEPTORS

Answer 4

TO DEFINE RECEPTORS
TO UNDERSTAND THE RATE OF LIGAND DRUG ACTION
TO FIND HOW MANY RECEPTORS ARE IN A GIVEN TISSUE
TO FIND HOW RECEPTOR NUMBERS CHANGE IN DISEASE

Question 5

WHAT IS EC50

Answer 5

THE EFFECTIVE CONCENTRATION GIVING 50% MAXIMAL RESPONSE

Question 6

WHAT IS A RECEPTOR RESERVE

Answer 6

MORE RECEPTORS EXIST THAN ARE NEEDED, IN THIS WAY NOT ALL RECEPTORS NEED TO BE OCCUPIED TO GIVE A MAXIMUM RESPONSE

Question 7

WHAT PERCENTAGE OF RECEPTORS IN THE GUT ARE RESERVE RECEPTORS

Answer 7

95%

Question 8

ON WHAT KIND OF DATA IS THE HILL EQUATION USED

Answer 8

CONCENTRATION RESPONSE CURVE

Question 9

WHEN MEASURED AGAINST OTHER DRUGS, THE DRUG WITH THE LOWEST EC50 IS CONSIDERED TO BE MOST ………..

Answer 9

POTENT

Question 10

THE POTENCY OF AN AGONIST DEPENDS ON WHAT 3 FACTORS

Answer 10

AFFINITY, EFFICACY AND SPARE RECEPTORS

Question 11

WHAT EFFICACY DOES AN AGONIST HAVE

Answer 11

1

Question 12

WHAT EFFICACY DOES A PARTIAL AGONIST HAVE

Answer 12

<1

Question 13

FOR A PARTIAL AGONIST, IN ORDER TO ELICIT A MAXIMUM RESPONSE THAT THE SPECIFIC DRUG IS CAPABLE OF, WHAT OCCUPANCY MUST IT HAVE

Answer 13

100%

Question 14

SINCE 100% OCCUPANCY IS REQUIRED FOR A SPECIFIC DRUG MAXIMUM WHEN THE DRUG IS A PARTIAL AGONIST, WHAT CAN BE SAID ABOUT KD

Answer 14

KD=EC50

Question 15

FOR A PARTIAL AGONIST WHERE KD=EC50, WHAT DOES THIS MEAN FOR ACQUIRING THE AFFINITY

Answer 15

YOU CAN USE A DOSE RESPONSE CURVE TO ACQUIRE THE AFFINITY OF A PARTIAL AGONIST

Question 16

WHAT DETERMINES THE EFFECT OF A DRUG IN A LIVING SYSTEM

Answer 16

SPECIFICITY
AFFINITY
EFFICACY

Question 17

WHAT IS ANTAGONISM

Answer 17

A DRUG THAT PREVENTS THE RESPONSE OF AN AGONIST

Question 18

WHAT ARE THE 5 CLASSES OF ANTAGONISM

Answer 18

1. CHEMICAL
2. PHARMACOKINETIC
3. PHYSIOLOGICAL
4. NON COMPETITIVE
5. COMPETITIVE BY RECEPTOR BLOCK

Question 19

WHAT IS CHEMCAL ANTAGONISM

Answer 19

SUBSTANCES COMBINE IN SOLUTION SO THE EFFECTS OF THE DRUG ARE LOST

Question 20

WHAT IS PHARMACOKINETIC ANTAGONISM

Answer 20

REDUCES THE AMOUNT OF ACTIVE DRUG BY CHANGING ABSORPTION, METABOLISM, CONSTIPATION

Question 21

WHAT IS PHYSIOLOGICAL ANTAGONISM

Answer 21

WHEN ONE DRUG ACTION COUNTERACTS ANOTHER DRUG ACTION

Question 22

WHAT IS NON COMPETITIVE ANTAGONISM

Answer 22

PREVENTS THE ACTION OF AN AGONIST BY ACTING DOWNSTREAM OF THE BINDING SITE OR IN A LOCATION OTHER THAN THE BINDING SITE

Question 23

WHAT IS COMPETITIVE ANTAGONISM BY RECEPTOR BLOCK

Answer 23

WORKS AT THE SAME SITE AS THE AGONIST TO REDUCE OCCUPANCY OF THE AGONIST

Question 24

HOW CAN COMPETITIVE ANTAGONISM BE OVERCOME

Answer 24

INCREASE THE CONC OF THE AGONIST TO REOCCUPY RECEPTOR AND DISPLACE THE ANTAGONIST

Question 25

GIVE AN EXAMPLE OF CHEMICAL ANTAGONISM

Answer 25

CHELATING AGENTS BIND TO HEAVY METALS TO INACTIVATE THEM

Question 26

GIVE AN EXAMPLE OF PHARMACOKINETIC ANTAGONISM

Answer 26

DIURETICS INCREASE URINATION THEREBY DECREASING THE CONC OF DRUG AS LOST IN URINE

Question 27

GIVE AN EXAMPLE OF PHYSIOLOGICAL ANTAGONISM

Answer 27

BRONCHODILATORS ARE COUNTERACTED BY BRONCHOCONSTRICTORS

Question 28

IN WHAT CASE COULD COMPETITIVE ANTAGONISM NOT BE OVERCOME

Answer 28

IF THE ANTAGONIST IS IRREVERSIBLE

Question 29

WHAT WOULD A CONCENTRATION RESPONSE CURVE LOOK LIKE FOR AN IRREVERSIBLE COMPETITIVE ANTAGONIST

Answer 29

MAXIMUM RESPONSE WILL ONLY BE ACHIEVED AS LONG AS THERE IS A RECEPTOR RESERVE BUT THIS IS TIME CONC DEPENDENT

Question 30

WE CAN MEASURE THE SHIFT OF A DOSE RESPONSE CURVE AT DIFFERENT CONCENTRATIONS OF AN ANTAGONIST ADDED TO AN AGONIST – WHAT IS THIS CALLED AND HOW IS IT CALCULATED

Answer 30

DOSE RATIO = CONC OF AGONIST IN PRESENCE OF ANTAGONIST/ CONC OF AGONIST IN ABSENCE OF ANTAGONIST

Question 31

WHAT EQUATION CAN SHOW THE RELATIONSHIP OF ANTAGONIST AFFINITY, DR AND AGONIST CONC.

Answer 31

DOSE RATIO = ([ANTAGONIST]/KD)+1

Question 32

WHAT IS A SCHILD ANALYSIS

Answer 32

THE RELATIONSHIP OF ANTAGONIST AFFINITY, DR AND AGONIST CONC.

Question 33

TO PLOT A SCHILD GRAPH, WHAT DR DO WE USE

Answer 33

DR=2

Question 34

WHAT AXES ARE ON A SCHILD GRAPH

Answer 34

LOG(ANTAGONIST) AGAINST LOG(DR-1)

Question 35

WHAT HAPPENS IN THE CASE OF IRREVERSIBLE COMPETITIVE ANTAGONISM

Answer 35

THE ANTAGONIST FORMS A COVALENT BOND AT THE RECEPTOR SITE

Question 36

THE POINT AT WHICH THE LINE CROSSES THE X AXIS IS CALLED WHAT

Answer 36

PA2

Question 37

WHAT DOES THE PA2 REPRESENT

Answer 37

A MEASURE OF AFFINITY - THE MOLAR CONCENTRATION OF ANTAGONIST THAT GIVES A DOSE RATIO OF 2

Question 38

WHAT IS THE PA2 EQUAL TO

Answer 38

-1LOGKD

Question 39

WHY MIGHT DESENSITISATION OCCUR

Answer 39

WHEN GIVEN CONTINUOUSLY OR REPEATEDLY

1. LOSS OF RECEPTORS FROM THE SURFACE
2. CHANGE IN THE RECEPTOR ITSELF
3. EXHAUSTION OF MEDIATORS
4. INCREASED METABOLIC DEGRADATION/EXTRUSION OF DRUG
5. PHYSIOLOGICAL ADAPTATION