Mechanisms of Drug-Receptor Interaction Flashcards
What does pharmacology include?
There are two main domains of pharmacology: medical pharmacology and toxicology, and environmental toxicology.
Medical pharmacology and toxicology can be further divided into pharmacokinetics (PK) and pharmacodynamics (PD)
Describe the history of pharmacology
Our first drugs most likely came from roots, berries, leaves and tree bark, etc. as evidenced by ancient well drawings and carvings.
We learned through trial and error.
Now we have evidence-based medicine (controlled clinical trials)
What is a drug?
Drug defined as any substance that brings about a change in biologic function through its chemical actions
What’s a substance?
A chemical species, pure element or species of matter
Describe the naming convention of drugs
Chemical name: e.g., acetylsalicylic acid
Code name: short hand method for defining a drug
Generic name: given by the government (Health Canada, FDA)
Trade/Brand name: given by the company
What is pharmacodynamics?
The actions of the drug on the body
Drug-receptor interaction
What is pharmacokinetic?
The actions of the body on the drug
ADME (main pillars of PK)
What are the two main mechanisms of drug action?
Non-receptor mechanisms (e.g., anti-infectives) Receptor mechanisms (e.g., NDMA)
What are 3 characteristics of a receptor?
- They determine the relationship between dose and effect
- Receptors are responsible for selectivity (if it’s not selective, you’re going to have all these other, most likely unwanted, biological responses)
- Receptors are responsible for the agonist or antagonist activity
What are the classifications of receptors?
Ion channels
G-protein-coupled receptors
Enzyme-linked receptors
Steroid receptors
Describe ion channel receptors
There’s a receptor that goes through the lipid bilayer. It’s selective as to what can pass through it. Most ion channel receptors have a gaiting mechanism (they only open when stimulated). E.g., NMDA is closed by the presence of Mg ion. When activated, the Mg ion dissociates and the receptor opens, allowing calcium to flow through
Describe G-protein-coupled receptors
When a ligand binds to the receptor, this causes the activation of a G-protein. The alpha subunit of the G-protein acts on the effector protein, causing a change in the cell
What are the three subtypes of enzyme-linked receptors?
Guanylyl cyclase
Tyrosine kinase receptors
Tyrosine kinase-associated receptors
Describe guanylyl cyclase
The receptor is located within the cell (not in the lipid bilayer) which means the drug has to get passed the lipid membrane (filtering process). It binds to the binding domain and the catalytic domain has some enzymatic conversion
Describe tyrosine kinase receptors
The span the membrane
Activation causes phosphorylation of a Tyr residue on a second messenger