Lecture 1 Flashcards
What is a receptor?
A biological molecule whose function is modulated (changed in some way) by a chemical combination with the drug. Another term for a drug receptor is target.
What is a drug?
An agent that alters the rate or extent of a biological process. Often referred to as a ligand. In modern pharmacology, drugs and receptors can be switched in that the receptor can be administered to change a response. But for the most part drugs refer to the ligand acting on the receptor. In some cases, receptors can have multiple binding sites.
What is pharmacokinetics?
Study of drug distribution, metabolism, and elimination in a living system. Adsorption, Distribution, Metabolism, Excretion.
What is pharmacodynamics?
Study of the interaction between drugs and receptors at the molecular level. Study of the binding of drugs to receptors.
What are some examples of drug receptors?
GPCR: Hormones: Neurotransmitters
Ligand-Gated Ion Channels: Neurotransmitters
Enzymes (COX)
Cotransporters
DNA (Nucleic Acids)
Signal Transduction Proteins (e.g. Kinases: potential target for cancer)
Structural Proteins (Microtubules)
Membranes and Bacterial Cell Walls
Ribosomes
Proteosomes: large macromolecular complex that degrades proteins
that are either misfolded or not meant to be expressed/ active at
certain points of the cell cycle. Proteosome inhibitors could be useful
in cancer therapeutics. Proteosome stimulators could be useful
in neurodegenerative diseases that involve aggregations of insoluble
misfolded proteins.
What are important parameters used to characterize a drug?
Potency, affinity, and efficacy.
What is drug potency?
The amount of drug required to elicit a certain biological response. Often described as the dose of a drug given. Can be quantified by the concentration of drug in some body fluid e.g. blood plasma. The lower the dose or concentration required to solicit a biological effect, the greater the potency.
What were Paul Ehrlichs important conceptual contributions to pharmacology?
- ) affinity: the attractive force between substances that causes them to enter into and remain in chemical combination.
- ) chemotherapy: using chemicals not created in the body to fight diseases.
- ) magic bullet: a drug that can kill microbes but not the person with the disease.
- ) lock and key: the idea that a drug molecule has a shape that fits the shape of the receptor site.
What’s a requirement for a magic bullet?
In order for a therapeutic agent to work, it has to be somewhat selective for the microbe so as to not kill the host too.
What is the idea of template action?
Idea of template action: A drug can modify the receptor by changing its structure in whats
called induced fit. Probably not the best explanation for how the immune system works, but
prions may utilize template action to convert folded proteins into misfolded aggregates.
How do you know that there is enough drug getting to where it needs to be?
Could take a biopsy,
grind it up, and measure the amount of drug present. An easier way would be to take a sample
of bodily fluid such as blood plasma. Can then measure the drug concentration and calculate
the concentration of drug present in the area of interest.
Methylene blue as a dye
Stain is not retained in the cytoplasm. Methylene blue intercalates the DNA and also binds to the phosphate backbone.
Methylene blue as a drug
Useful in the treatment of malaria. Was an early treatment. Could be used when the malaria is resistant to all of the other drugs. . When its exposed to light it undergoes a conformational change that makes it useful as an antibacterial agent. There are many other options for antibacterial agents, but as drug resistance becomes
more prevalent, it can be used more and more. Its backbone was used
to develop tricyclic antidepressants. Tricycs are also used to treat
anxiety and other psychiatric disorders.
Why do most drugs interact through non-covalent interactions? Give an example of a drug that acts through a covalent interaction.
You want a reaction that is reversible because most of the target molecules are essential to normal function. If using a covalent interacting drug, you may inhibit these target molecules too much. The exception is if the body can easily churn out more of the target relatively fast so as to minimize the negative impact the
covalent drug would have on the bodies normal function. Aspirin is an example of an acetylating acting drug that works to “kill” COX enzymes. The body can make more COX back to normal levels in about 4 hours so its ok. Platelets cant make new COX though, so they are permanently inhibited so there is still potential for overdose.
What is the lock and key model?
Interacting groups in the structure of a drug and it’s receptor must be positioned very close to each other in order for the chemical bonds that hold the two together to form. This requires that the drug must fit tightly into the 3-D structure of the receptor.