Pharmacology-Agonists-Part 2 & Anatagonist

Question 1

Thalomid

Answer 1

• Risk out weigh benifit as previously used to treat nausea in pregnant women causes deformity to children

Question 2

Antagonist response

Answer 2

• Antagonist binding to receptors on the cell
• Opposes the agonist binding therefore cannot produce physological response

Question 3

What is kD

Answer 3

• Concentration of the drug required to occupy 50% of the receptor measuring drug affinity (dissociation constent

Question 4

What is kA

Answer 4

• Association constent which is the reciprocal of kD
• Lower kD value higher affinity

Question 5

Sigmond curve

Answer 5

• Convert concentration of dose to log dose
• Calculate the 50% receptor occupency

Question 6

Agonist potency

Answer 6

• Effective concentration of agonist 50% response

Question 7

Maximal effect

Answer 7

• Saturate the receptor
• How well the receptor can produce the conformation

Question 8

Potency lower han affinity

Answer 8

• At EC50 the drug effect occour when the drug binding just starts to occour

Question 9

Amplification of signals

Answer 9

• Ions flow through channels second messenger mRNA molecules for new protiens
• Reserve receptors only need 50% bind for physological response

Question 10

Partial agonist

Answer 10

• Produces less than 100% max response with all receptors bound
• Left shift on graph for partial agonist so more potent

Question 11

Non-competitive antagonism

Answer 11

• Glutamate (endogenous hormone) binding site at ligand gated ion channel (NMDA receptor)
• Enable calcium and sodium influx
• Mementine blocks the ion channel pore not allowing movement of sodium and calcum inside (antagonist)
• Don’t need matching chemical signature

Question 12

Where does the non-competitive antagonist bind

Answer 12

• Allosteric binding site place elsewere to the active site
• Modulate endogenous agonist response

Question 13

Reversible antagonist

Answer 13

• Can dissociate from the receptor compete with the agonist
• Reduction of physological response rate
• Increase in agonist concentration - maximal response achived increase potency

Question 14

Irreversible competitive antagonist

Answer 14

• Irreversible antagonists form covalent link with receptor
• This means that occupancy for maximum agonist decreases as it cannot bind to the receptor
• No more receptor reserve, agonist response declines

Question 15

non-surmountable antagonism

Answer 15

• The agonist EC50/potency is first declines as receptor reserve decreases.
• Further, the agonists maximum response drops

Question 16

Chemical antagonism

Answer 16

• Base neutralise the acid, to
  relief acid reflex, heart burn
• Heavy metal chelators
• Antibody therapy
• Avastin

Question 17

Pharmocokenetic antagonism

Decreased absorption

Answer 17

• Anti-diarrhoeal drugs inhibit gut absorption of other drugs
• vasoconstriction by adrenaline restricts distribution of local anaesthetics

Question 18

Pharmocokenetic antagonism

Increased metabolism

Answer 18

Phenobarbital increases liver enzyme activity and
stimulates metabolism of many drugs, including warfarin

Question 19

Physological antagonism

Answer 19

• blood pressure regulation by DIURETICS
• diuretics increases the urine output and by which it reduces the sympathetic control of blood pressure (by adrenaline)