Quiz 1 Exam 2 Flashcards
Define drug resistance.
Drug resistance is the development of a reduced drug response.
What are the 5 causes for drug resistance?
- Increased efflux (PK)
- Decreased uptake (PK)
- Drug inactivation (PK)
- Mutations in the drug target (PD)
- Reversal of drug action (PD)
__________ is an example of intrinsic drug resistance.
MRSA (Methicillin-resistant Staphylococcus aureus)
Intrinsic in terms of drug resistance means it will have no initial response to the drug.
What is intrinsic drug resistance?
This is the innate ability of a species to resist the action of a drug as a consequence of the structural or functional characteristics of that species
What is acquired drug resistance?
Occurs when the species acquires the ability to resist the actions of a particular drug
What is an example of a ligand-gated ion channel?
The nicotinic receptor. This receptor is bound by acetylcholine and allows for the passage of Na+ into the cell.
How many subunits are on the nicotinic receptor?
5 subunits; 2 alpha, 1 beta, 1 gamma, and 1 delta unit.
Where does acetylcholine bind on the nicotinic receptor?
Acetylcholine molecules bind to the 2 alpha subunits on the nicotinic receptor.
In the human genome, ______- _______ genes code for transport proteins.
500-1200
What is a basolateral membrane?
The basolateral membrane has contact with the blood vessel and the epithelial cell.
What is an apical membrane?
The apical membrane is the surface of the cell that faces the lumen.
Are transporter/carrier proteins faster or slower than ion channels?
Transporter/carrier proteins are much slower than ion channels as they are more complex.
What are the two types of transporter-carrier proteins?
Active (require energy and go against conc. gradient) and passive (no energy and go with conc. gradient)
What is the main efflux transporter?
ABCs (ATP-Binding Cassette Proteins)
What are the main uptake/influx transporters?
SLCs (Solute Carrier Family)
Efflux transporters like the ABCs contribute to __________________.
Multi-drug resistance
Efflux transporters like ABCs typically contain __ nucleotide bindings domains and at least 2 _______________ domains.
2
Transmembrane
What do the transmembrane domains on efflux transporters like the ABCs define?
The transmembrane domains on ABCs define substrate specificity, which is typically very broad.
What is the evolutionary reason for the development of efflux transporters?
They prevent toxins from entering vital organs at BBB, BTB, placenta, and ovaries.
What are the 3 genes families of efflux transporters?
- MDR1 (ABCB1, p-glycoproteins)
- MRPs (Multi-drug Resistance Proteins)
- MXR (BCRP-breast cancer resistance protein)
Increased activity of multi-drug resistance pumps like ABCB1, ABCC1, and ABCG2 _________ resistance to anti-cancer drugs.
Increases
(B1, C1, and G2)
How do ABC efflux transporters transport things out of the cell?
They bind ATP and become a barrel shape to form a pore with a 5 nanometer diameter.
What are the general characteristics of substances effluxed by MDR1/ ABCB1/ p-glycoprotein?
Hydrophobic neutral and cationic compounds. Very broad in general though.
What are the 4 compounds discussed that inhibit MDR1?
Tamoxifen
Progesterone
Cyclosporin A
Quinidine