Lec 2

action

**Ibuprofen inhibits the cyclooxygenase enzyme.**

This is the *(action/effect)* of the Ibuprofen drug.

effect

**Ibuprofen relieves pain & fever and reduces inflammation.**

These are the *(actions/effects)* of the Ibuprofen drug.

Drug action

The mechanism by which a drug produces an effect

Drug effect

The biological response after a drug is administered

subtherapeutic, therapeutic/beneficial, harmful

Drug effect may be:

toxic & lethal

two types of harmful effects of drugs

receptor-mediated, nonreceptor-mediated

Drug action may be:

receptor

a specialized macromolecule involved in cell signaling that binds a ligand

protein or glycoprotein

nature of receptors

enzyme-linked receptor

receptors with a kinase domain

G-protein-coupled receptors (GPCRs)

largest family of receptors

guanine nucleotide-binding protein

G-protein

Ion channel receptor

modulated the passage of ions and hydrophilic molecules

ligand-gated, voltage-dependent

types of ion channel receptor

ligand-gated ion channel receptor

opens in response to a chemical signal/ligand

voltage-dependent ion channel receptor

opens in response to voltage, i.e. when the membrane gets depolarized

transcription factor receptor

receptors for fat-soluble signaling molecules

cytosol

transcription factor receptors are located in the ___ and migrates to the nucleus after binding with the ligand

transcription factor

what is the receptor class of the steroid hormone estrogen?

ionic bond

formed by the attraction between 2 ions of opposite charge

ionic bond

the most commonly occurring bond

hydrogen bond

arises from the ability of a proton (H+) to accept an electron pair from a donor (e.g. oxygen) & another donor (oxygen or N)

van der waals

form a very weak bond between dipoles or induced dipoles

covalent bond

tight and practically irreversible

covalent bond

rare during drug-receptor interactions except in toxic situations

ionic bond, hydrogen bond, van der waals

the principal bond forces involved in drug action

20-40°C

at what temperatures do the principal bond forces become easily reversible?

50-100 kcal/mol

What amount of energy is required to break covalent bonds?

cell signaling

relates to cell communication and the intracellular responses generated in response to drugs and endogenous ligands

reception

during this process, a chemical message/ligand binds to a cell surface receptor

transduction

a cascade of reactions that elicit cellular response

signal transduction

a mechanism by which cell surface receive information & amplify this information through action of second messengers

second messengers

molecules produced in response to ligand-receptor binding that translate the extracellular signal into a response that may be further propagated or amplified within the cell

response

may vary from activating a gene or an enzyme, or rearranging the cytoskeleton

neutralization reactions, nonspecific perturbation of cell membrane, binding with small molecules and ions (chelation)

non receptor-mediated drug action

enzyme-linked, G-protein-coupled, Ion channel

cell-surface receptors

transcription factor receptors

intracellular/cytoplasmic receptors