Week 2: Pharmacodynamics Flashcards
What is pharmacodynamics?
What the drug does to the body - almost all drugs act through receptors located on or in the cells - drugs combine to a receptor and produce an effect
What is a ligand?
a molecule that binds with a molecular target (receptor) - also called a 1st messenger or a signaling molecule
What are 2 types of ligands?
Endogenous (comes from within the body) ex: hormones, neurotransmitters
Exogenous (comes from outside the body) ex: drugs
What type of ligand can be both endogenous and exogenous?
Insulin - is produced by the body, but can also be given exogenously to diabetics
What is an example of a drug that acts through a chemical reaction other molecules?
antacids that neutralize stomach acids - act directly
Can a drug create an effect?
No - drugs modulate functions already present in the cell or tissue
What things can affect pharmacodynamics?
- age
- sex
- ethnicity
- individual characteristics of a person
What are the three steps of pharmacodynamics/cellular communication?
1) Signal recognition
2) Signal transduction
3) Cellular response
What are the four types of cellular communication?
1) Ion Channel Receptors / Ligand Gated Ion Channel
2) G-protein coupled Receptors
3) Transmembrane Receptors
4) Intracellular Receptors
How do ion channel receptors transmit signals across the cell membrane?
a signal molecule activates the ion channel receptor which increases the flow of ions across the cell membrane which alters the electrical potential of the cell or by separating changed ions across the membrane. - Example: acetylcholine which momentarily opens a central channel allowing sodium to enter a cell and potassium to leave the cell
How do G Protein Coupled Receptors (GPCR) transmit signals across the cell membrane?
a G-protein receptor is activated when specific drug interact with the binding site which causes a conformational change, a sort of twist of the G-protein - activation of the receptor produces intracellular changes in the G-protein receptor to other proteins that control response through other molecules called second messengers
What is one type of second messenger involved in G-Protein Coupled Receptor cellular communication?
Cyclic adenosine monophosphate (cAMP)
G-proteins are made up of what three major subunits?
1) alpha agonist
2) beta agonist
3) gamma agonist
How do transmembrane receptors transmit signals across the cell membrane?
And extracellular hormone binding domain is bound by a ligand - when an active hormone binds to the binding site, the receptor conformation changes and two receptors bind to each other, activating the intracellular enzyme domain and causing the receptors to catalyze the phosphorylation of tyrosine residues on various downstream signaling proteins
How do intracellular receptors work to regulate gene expression?
Hormones that are lipid-soluble and able to readily cross the cell membrane into the cell bind to glucocorticoid receptors in the cell’s cytoplasm. This binding displaces a stabilizing protein and permits the receptor to change into it’s active conformation - the receptor moves into the cell’s nucleus where it binds to specific DNA sequences and alters the transcription of genes