lecture 1 Flashcards
Agonists,antagonists and potency
What is Pharmacology ?
study of drug action and mechanism underlying this action in living organisms
What is a drug ?
chemical substance of known structure that produces a biological effect when administered to a living organisms
Rang & Dale
eg) :paracetamol
Aspirin
Whats a chemical name ?
When its discovered fully organic chemitry name
Whats a generic name ?
given once a drug is approved
aka : paracetamol or acetaminophen
What is a trade or brand name ?
given my company for marketing purposes until patent runs out
panadol
tylenol
The origins of drugs ?
before 1800s most drugs were extracted from plants used as herbal remedies
eg.)Quinine
Digitoxin
Atropine
What is the receptor concept (Ehrlich and Langley ) ?
Receptors respond and recognise specific molecule
alters cell function and sensing molecules
Drugs that activate and bind = AGONIST
bind but prod no response =ANTAGONIST
Define receptor ?
used to denote a class of cellul;ar macromolecule that is involved in specific chemical ignalling between and within cells
Some eg of Receptors ?
- Ligand gated ion channels
2.G-protein coupled receptors
3.Tyrosine-kinase linked receptors
4.Nuclear receptors
Targets of drug action ?
Receptors are not enzymes
enzymes=protein catalysts of a biochemical reaction and substrate usually altered
DRUG INTERACTION DOES NOT CHANGE THE DRUG
Properties of Receptors ?
- Saturability
- Reversibility
- Encoded by a gene
- Specificity to a ligand
Define Saturability ?
majority of receptors
no of receptors are limited
only a certain concentration of drug that can be bound to a certain amount of tissue
Define Reversibility ?
interaction with receptor with the ligand is not permanent
act ina reversible way:removal leads to recovery of receptor in its natural function
assume they obey law of mass
What is encoded by a gene ?
specific populations of receptors proteins exist
these prod specific subtypes
affinity between subtypes of receptors and different agonists will be unique
essential to identify gene that encodes for specific receptor
Define Specificity to ligands ?
necessary to criticism
Relationship between against conc and receptor occupancy ?
law of mass action states that the rate of reaction is proportional to the product of the conc of reactants
Why do we care about the relationship between agonist concentration and receptor occupancy ?
predicts the relationship between receptor occupancy agonist concentration
How does receptor occupancy relate to tissue response ?
maximal response may occur when an agonist occupies less than 10% of available rececptors
shaope of cconcntrations repsons curve cannot be explained by these
relationship between agonist conc and tissue response can be described using this empirical (hill)
What is the Hill-Langmuir equation ?
describes the relationship between agonist-receptor occupancy vs agonist conc
What is the Hill equation ?
describes relationship between tissue response vs agonist concentration
What does the EC50 tell us ?
affected by affinity and efficacy
about agonist efficacy
What is agonist efficacy ?
the ability of to induce a response
What are EC50s are useful for comparing the potency of 2 agonists acting on a tissue ?
potency can be measured using EC50s
gives an indication of how efficient one drug is at eliciting a response compared to another
What does potency ratios allow us ?
allow us to compare the effects of standard and unknown drugs ?
