Cell Communication Lecture 4 – How drugs Act (general principles)
What is a drug?
“a chemical that produces a biological effect when given to a living organism”
(Though note FDA definition includes,
its structure must be known
not a nutrient or essential dietary ingredient)
A medicine is... “a chemical preparation usually containing one or more drugs but also including
other components e.g. stabiliser, solvent”
Where do drugs come from?
From plants - e.g. opioids, aspirin, cocaine
From fungi – e.g. penicillin, cyclosporins, statins
From microorganisms – e.g. rapamycin
Synthetic chemicals – e.g. benzodiazepines, local anaesthetics
From animals (often chemically modified to improve their pharmacological properties) – e.g.
insulin
Biologics/Biopharmaceuticals - a wide range of medicinal products such as vaccines, humanised
monoclonal antibodies and hormones created by biological processes, usually involving recombinant
DNA technology.
Principles of Drug interactions with their targets – Agonists
Selectivity and specificity of Drug Action:
Drugs must have a selective action on a tissue or cell type.
Selective drug action reflects specific expression patterns of protein drug targets.
The interaction (“binding”) between drug and drug target must show a high degree of
specificity.
Thus, drug targets only recognise chemical structures of a precise type ignoring closely
related molecules.
Specificity is never absolute.
Drugs often interact with more than one protein target, particularly at high doses. This is one source
of unwanted actions or “side-effects” of some drugs.
“Receptors” as Drug Targets
Receptor = “A protein or protein complex whose function is to recognise and respond to
endogenous chemical signals” !!!!
i.e. Ligand-gated ion channel, G protein-coupled receptor, catalytic receptors, nuclear receptors
(Broader definition of a receptor)
drug target = Any target molecule with which a drug must combine in order to elicit its specific
effect” i.e receptors, ion channels, enzymes, transporters
Properties Of Ligand – Receptor Interactions
Ligand= Any drugs which binds with specificity to a molecular (protein) target.
What is a drug?
“a chemical that produces a biological effect when given to a living organism”
(Though note FDA definition includes,
its structure must be known
not a nutrient or essential dietary ingredient)
A medicine is... “a chemical preparation usually containing one or more drugs but also including
other components e.g. stabiliser, solvent”
Where do drugs come from?
From plants - e.g. opioids, aspirin, cocaine
From fungi – e.g. penicillin, cyclosporins, statins
From microorganisms – e.g. rapamycin
Synthetic chemicals – e.g. benzodiazepines, local anaesthetics
From animals (often chemically modified to improve their pharmacological properties) – e.g.
insulin
Biologics/Biopharmaceuticals - a wide range of medicinal products such as vaccines, humanised
monoclonal antibodies and hormones created by biological processes, usually involving recombinant
DNA technology.
Principles of Drug interactions with their targets – Agonists
Selectivity and specificity of Drug Action:
Drugs must have a selective action on a tissue or cell type.
Selective drug action reflects specific expression patterns of protein drug targets.
The interaction (“binding”) between drug and drug target must show a high degree of
specificity.
Thus, drug targets only recognise chemical structures of a precise type ignoring closely
related molecules.
Specificity is never absolute.
Drugs often interact with more than one protein target, particularly at high doses. This is one source
of unwanted actions or “side-effects” of some drugs.
“Receptors” as Drug Targets
Receptor = “A protein or protein complex whose function is to recognise and respond to
endogenous chemical signals” !!!!
i.e. Ligand-gated ion channel, G protein-coupled receptor, catalytic receptors, nuclear receptors
(Broader definition of a receptor)
drug target = Any target molecule with which a drug must combine in order to elicit its specific
effect” i.e receptors, ion channels, enzymes, transporters
Properties Of Ligand – Receptor Interactions
Ligand= Any drugs which binds with specificity to a molecular (protein) target.
