Part 1 Flashcards
Define a receptor
Target proteins through which endogenous regulatory ligands produce an effect
List the 4 types of drug targets
Enzymes
Physiologic receptors
Ion channels
Carrier transporters
Examples of common drug targets
Acetylcholine, adrenergic receptors , histamine, opioid, steroid, cytokine
Explain how methotrexate is used to fight cancer
Methotrexate binds to the target receptor, dihydropholate reductase which is important for the synthesis of purines which are building blocks of RNA and DNA. This reduces the rapid division of cells in cancer
Name 2 physiologic receptors and their agonists and antagonists
B-adrenoceptor
Agonist- noradrenaline, isoprenaline
Antagonist- propranolol
Opioate
Agonist- morphine
Antagonist- neloxone
Effects of adrenaline (epinephrine) on the heart
Adrenaline binds
List ion channels and their blockers and modulators
Voltage gated Na channels
Blockers - local anaesthetics, tetrodoxin
Modulator- veratridine
GABA gated Cl channels
Blockers-picrotoxin
Modulators-benzodiazepines
Which animal has tetrodoxin
Fugu(pupperfish)
Give examples of the types of transmembrane receptors
- Ligand-gated ion channel- cholinergic nicotinic receptors eg acetylcholine
- G-protein coupled- a and b adrenoceptors eg noradrenaline
*Enzyme-linked receptors- insulin eg insulin - Intracellular receptors- steroid receptors eg oestrosdial
Define activation of receptor
When the drug is bound to receptor and causes the receptor to elicit a cellular response
Differentiate between agonist and antagonist
Agonist- a drug that binds to a receptor and causes the receptor to become activated
Have high efficacy
Antagonist- a drug that binds to a receptor but does not cause activation and prevents the agonist from binding
Have zero efficacy
Efficacy
Ability to produce desired outcome
Affinity
The degree to which the drug binds to receptor
How much the drug wants to bind to receptor
Potency
How strong or effective the drug is
Differentiate between partial and full agonists
Partial- drugs with intermediate levels of efficacy such that even at 100% occupancy of the receptors, the drug only causes tissue response of submaximal effect
Full agonists- Have enough efficacy to cause maximal tissue response
Define the law of mass action
The rate of a chemical reaction is proportional to the concentration of reaction substances
KD
The amount of the drug that is not bound
Explain the lower the KD the higher the affinity
Because when KD is low then there are few drugs that are not bound meaning most of the drugs are bound so there is high affinity
Also binding (occupation) always associated with affinity
Equilibrium association constant
Reciprocal of dissociation contant
How much of the drug is bound
The higher the KA the higher the affinity
List drug transport proteins and their inhibitors
Noradrenaline transporter- tricylclic antidepressants
Proton pump-omeprazole
Name enzymes and inhibitors
Cyclo-oxygenase - aspirin and other NSAIDS
HMG-CoA reductase-simivistatin
Dihydrofolate reductase- methotrexate
