Introduction to Pharmacology - Lecture 1 Flashcards
What does a Endogenous substance mean?
Refers to a substance from within the body
What does a Exogenous Substance mean?
Refers to a substance from outside the body
What does Pharmacology comprise of?
Pharmacodynamics
Phamcokinetics
What is Pharmacodynamics?
This is what a drug does to the body (Biological effects and mechanism of action)
What is Pharmacokinetics?
This is what the body does to a drug (Absorption, distribution, Metabolism, Elimination)
What is a drug?
Any synthetic or natural substance that is used in the treatment or prevent of disease
What must a drug have to be effective as a therapeutic agent?
A degree of selectivity
- Targets a particular biological process
How do drugs act?
Act by binding to target molecules
- Lock and Key Hypothesis
How is selectivity achieved for drugs?
The Chemical structure of the drug is only recognised by the target receptors
What do drugs general bind to, to cause an effect?
Enzymes Carrier Molecules Ion Channels Receptors RNA DNA
What is a receptor?
Receptors are macromolecules that mediate the biological actions of hormones and neurotransmitters
Drugs acting on receptors can act in two ways - what are these ways?
As an Agonist
As an Antagonists
What is a ligand?
A molecules that binds to another l(usually larger) molecule
What is an agonist?
A substance that binds to a receptor to produce a cellular response
What is an antagonist?
A substance that blocks the actions of an agonist. `
What does an agonist do to the receptor?
Agonist binding causes a conformation change in a receptor
What is the equation to define an agonist’s reaction with a receptor?
A + R AR AR* (activated)
What is the efficacy of a reaction?
Efficacy is the ability of an agonist to evoke a cellular response
What is the affinity of a reaction?
Affinity is the strength of association between a ligand and a receptor
(The longer the agonist stays on the receptor the higher the affinity)
What is the term used when the receptors are 100% occupied?
Saturation point
What is the relationship between receptor occupancy and agonist concentration?
Hyperbolic
What is the Effective Concentration 50?
EC50 is the concentration of agonist that elicits a half maximal response (At which 50% of the receptors are occupied)
What is the symbol given for Effective Concentration 50?
EC50
What type of graph is often used instead of a hyperbola?
Semi-logarithmic plot (Response % vs Agonist concentration)
EC50 can still be calculated