1. Receptors I Flashcards
Define an Agonist.
A chemical causing a conformational change in a receptor causing a specific biological characteristic.
Define an Antagonist.
A chemical not causing a conformational change in a receptor but blocking it.
Define a Receptor.
A macromolecular component of a cell with which a drug interacts with to produce its characteristic biological effect.
Give the 4 properties of a Receptor.
-Present in low concentrations in a tissue and shows saturable binding.
- Drug receptor complexes are usually fully reversible.
- Receptors show selectivity.
- Receptors have a binding site with complementary structure to the drug.
Give the three properties of Drugs in relation to Receptors.
- Many drugs have high affinities for their receptors.
- Drugs are usually small molecules.
- Drugs are only held by weak binding forces so a close fit is required.
Define Saturable binding.
This means there are a finite number of binding sites so at a high concentration, all receptors will be fully saturated.
Define Efficacy.
The strength of a biological characteristic created from an agonist.
Define the Affinity of a drug.
The drugs ability to bind to its receptor measured by the equilibrium constant Kd.
Define Selectivity of Receptors.
The receptor is capable of binding similar agonists or different isomers with different affinities.
Describe Nicotine’s effect on muscle.
Agonist, when applied to muscle causes a contraction.
Describe Curare’s effect on muscle.
antagonist by applying to muscle then nicotine elicited no response but when an electrical charge was put into muscle it did contract.
Define a Micromole.
Mol 10^-6.
Define a Nanomole.
Mol 10^-9
Define a Picomole.
Mol 10^-12
Define a Femtomole.
Mol 10^-15
