Basic Drug Pharmacology Flashcards
1
Q
What 4 main kinds of regulatory proteins are commonly involved as primary drug targets ?
A
• Receptors
• Enzymes
• Carrier molecules (transporters)
• Ion channels
2
Q
What is a receptor ?
A
- a target molecule through which soluble physiological mediators produce their effect
3
Q
What is the process of drug-receptor interaction?
A
- Ligand binds to a receptor.
- Forms a ligand-receptor complex.
- Triggers a response or multiple responses.
4
Q
What are the 4 main receptor classes + their response times in drug-receptor interactions ?
A
- ligand-gated ion channels = minutes
- G - protein coupled receptors = seconds
- enzyme - linked receptors = hours
- intracellular receptors = hours
5
Q
What are key points about drug-receptor interactions ?
A
- drugs exhibit high structure and specificity to produce pharmacological effects.
- interact with receptor sites located in macromolecules with protein-like properties and specific 3D shapes
- a minimum three-point attachment is required for a drug to bind effectively to a receptor site.
6
Q
What types of bonds are involved in drug-receptor interactions, and how common are covalent bonds?
A
- any bond can be involved in drug-receptor interactions
- covalent bonds are very tight and practically irreversible
- so they are rare because drug-receptor interaction is reversible , except in a toxic situation
7
Q
What are the 3 main types of receptor binding experiments ?
A
- Kinetic experiments = measure binding of one or more radioligand concentrations over a series of time points
- Saturation experiments = measure binding of increasing concentrations of radioligand
- Competition/modulation experiments = measuring radioligand binding at equilibrium in the presence of increasing concentrations of a non-labeled compound
8
Q
What is an agonist in drug-receptor interactions ?
A
- a substance that interacts with a specific cellular constituent
- elicits an observable biological response
- can be endogenous (neurotransmitter) or exogenous (outside body )
9
Q
What is a partial agonists in drug-receptor interactions ?
A
- acts on the same receptor as agonists,
however, regardless of its dose it cannot produce the same maximal biological response as a full agonist
10
Q
What is an inverse agonist (negative antagonist) ?
A
- acts on the same receptor of the agonist yet produces an inverse effect
11
Q
What is a spare receptor in drug-receptor interactions ?
A
- receptor that exists in excess of what is needed to produce a full biological effect
- not different from other receptors
12
Q
What is intrinsic activity in drug-receptor interactions ?
A
- proportionality constant of the ability of the agonist to activate the receptor compared to the maximally active compound ( most effective) in the series being studied
13
Q
What is an antagonist ?
A
- Inhibits the effect of an agonist but has no
biological activity of its own. - may compete on the same receptor site that the agonist occupies or it may act on allosteric site.
14
Q
What are the 4 types of antagonists ?
A
- Competitive: antagonist binds to same site as agonist in a reversible manner.
- Noncompetitive: antagonist binds to the same site as agonist irreversibly.
-
Allosteric: antagonist and agonist bind to different site on same receptor
• Physiologic: Two drugs have opposite effects through differing mechanism
15
Q
What is a heteroreceptor in drug receptor interactions ?
A
- receptor that regulates the synthesis and/or
the release of chemical mediators other than its own ligand.
16
Q
What is an autoreceptor ?
A
- macromolecule typically found in the nerve
ending that regulates the synthesis and/or the release of its own ligand
17
Q
What is receptor down-regulation ?
A
- agonist induces a decrease in no of receptors available for binding
18
Q
What is receptor up regulation ?
A
- agonist induces an increase in the number of receptors available for binding
19
Q
What is affinity ?
A
- the ability of a drug to combine with a receptor
- it is proportional to the binding equilibrium constant KD
- ligand of low affinity requires higher conc of drug to produce the same effect
- both agonists and antagonists have affinity to the receptor
20
Q
What is efficacy ?
A
- measure of the biochemical or physiological effect that results from the drug binding to the target
- represents the maximum effect the drug can produce
21
Q
What is potency + what does it depend upon ?
A
- refers to the dose of a drug required to produce a specific effect, usually 50% of the maximum effect
- depends upon both affinity + efficacy
22
Q
What are ligands ?
A
- substances, molecules or compounds which bind to receptors present in the body
- eg acetyl chole, adrenaline, noradrenaline, neurotransmitters
23
Q
What are the effects of ligands on the receptor ?
A
- resemble the natural ligand, activating the receptor in a similar way
- block the natural ligand, preventing it from binding and activating the receptor
24
Q
What are 2 properties do agonists have ?
A
- Affinity for receptor
• Capability to produce chain reactions in the cells having capability of intrinsic activity or efficacy
25
What do agonists cause ?
- when binding to receptors they cause activation of receptors
26
What is the action of a drug ?
- biochemical or physiological mechanisms by which the drug produces a response in the body.
- e.g - the action of penicillin is to interfere with cell wall synthesis in bacteria.
27
What is the effect of a drug ?
- the observable consequence of a drug action
- e.g - the effect of penicillin is the death of the
bacteria.
28
What does a dose-response curve represent?
- shows the relationship between the dose of a drug and the magnitude of its effect
29
What is the threshold in a dose-response curve?
- threshold is the smallest dose of a drug that produces a measurable effect.
30
What is the ceiling in a dose-response curve?
- the maximum effect that a drug can produce, even with increasing doses.
31
What does ED50 stand for?
- ED50 stands for Effective Dose 50
- the dose of a drug required to produce 50% of the drug’s maximal response.
