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Flashcards in Drug Action Deck (14)
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1
Q

What is a quantal response? (1)

A

All or nothing response

2
Q

What are some factors that affect response? (5)

A
  1. Age
  2. Genetics
  3. Previous Exposure
  4. Enzyme Activity
  5. Body Composition
3
Q

How can Affinity be represented in chemical equation? (2)

A

Association contant/Dissociation constant

4
Q

What are the differences between competitive Antagonist and non-competitive Antagonist? (4)

A

Competitive antagonist - Competes with agonist for same receptor. This slows than effect of agonist but eventually agonist out-competes to produce maximum response.

Non-competitive antagonist - Binds irreversibly with receptor (at active site or different site) so agonist cannot bind. This is allosteric effect to inactivate receptor. Therefore maximum response is NOT obtained.

5
Q

What is a constitutively-active receptor? What are some examples? (3)

A

A receptor that produces background activity even without agonist.

The receptor has a slightly more active state than other receptors.

e.g some GABA receptors, histamine receptors.

6
Q

At what state do agonists have more affinity on receptors? (2)

A

Agonists have more affinity for receptors when they are in their active state, and less affinity in resting state.

Therefore in active state, the receptor produces increased response.

7
Q

What is an inverse Agonist? (2)

A

Opposite effect of agonist, has increased affinity for receptor in resting state, than in active state.

8
Q

What effect do neutral Antagonists have on receptors? (2)

A

They have equal affinity for both resting and active states of receptors, hence slow down or stop effect.

Does not have effect on Resting to Active equilibrium.

9
Q

What does GABA stand for? What does it do?

How does it prevent Action Potential in Brian Cells?

A

GABA - Gamma aminobutyric acid. It is the predominant inhibitory neurotransmitter in brain.

It binds to GABAa (Ion Channel (Type 1 Recptor)) Receptor in brain and allows Cl- to enter cell to make depolarisation difficult.

This stabilises tissue and produces sedation.

10
Q

What agonists bind to G-coupled proteins with Beta2 Receptors (Type 2 receptors)?

How does this work and what effect does it produce? (5)

A

Noradrenaline and Adrenaline.

They bind to Beta 2 receptor, causing activation of G protein.

G Protein activates Adenylyl cyclase.

Adenylyl cyclase activates cAMP (second messenger), which activates Protein Kinase

This leads to Smooth muscle relaxation and Bronchodilation.

11
Q

How does Asthma lead to Bronchoconstriction?

What drug reverses this? (3)

A

In Asthma the beta 2 receptor and the intracellular pathway is unresponsive to agonists.

This leads to less smooth muscle relaxation hence bronchoconstriction.

Salbutamol acts as a synthetic agonist to stimulate receptor and leads to Bronchodilation.

12
Q

What receptors are Type 3 receptors?

How do they work? (3)

A

Enzyme-linked receptors.

When agonist binds to receptor, this triggers a cascade of phosphorylation intracellularly leading to cellular effect.

13
Q

What receptors are type 4 receptors?

How do they work? (3)

A

Nuclear (intracellularly) Receptors. Also called Steroid Hormone receptors.

They normally inactive in cytosol but when activated by agonist, they move into nucleus to control gene expression and protein synthesis.

14
Q

What is the time difference between all the receptor types? (2)

A

Type 1 receptor (Ion channel linked) acts in milliseconds

Type 2 receptor (G coupled protein) acts in seconds

Type 3 receptor (Enzyme linked) acts in minutes

Type 4 receptors (Nuclear) acts in hours.