lecture 4 - pharmacodynamics Flashcards
know the diagram in lecture
what is a ligand?
molecule that binds to a receptor with some selectivity
what are receptors?
proteins on cell surfaces or within cells
what are types of receptors?
- heteroreceptors: regulate the release of neurotransmitters other than their own (pre and post)
- autoreceptors: regulate the release of their own neurotransmitter (pre)
what are allosteric binding sites?
distinct site on the surface of the receptor different from where the neurotransmitter binds – impacts function of receptor
what is binding affinity?
refers to strength of the bond between drug and receptor
when changes can occur when a drug (ligand) binds?
produced an EPSP (depolarizes - more likely for an AP)
produced and IPSP (hyperpolarizes - less likely for an AP)
what are characteristics of the receptors of the drug itself?
- have a particular life span
- number and sensitivity of receptors can also change
what is up regulation?
making MORE receptors - so more receptors available to interact with drugs
what is down regulation?
make LESS receptors in response to absence of ligand or chronic activation
what is a receptor efficacy?
drug’s ability to alter the activity of the receptor (ex. can the key actually turn the lock)
basically comparing the response that the drug produces compared to what an endogenous ligan would normally produce there
what are full agonists interactions?
- has binding affinity (drug fits into lock)
- has receptor efficacy
- produced SAME biological response as the endogenous ligand would and ACTIVATES the neurotransmitter receptor
if an agonist binds to a neurotransmitter receptor, what occurs?
depends on type of receptor
so either EPSPs or IPSPs
what are receptor antagonist interactions?
- binding affinity (a stick fits in the lock)
- low or NO receptor efficacy (the stick jams it)
- can prevent the active ligands from binding
if an antagonist binds to an excitatory receptor, what happens?
nothing happens
if an antagonist binds to an inhibitory receptor, what happens?
EPSP - the activity continues
what interaction does a competitive antagonist do?
- binds to same site as neurotransmitter
- prevent neurotransmitter from binding
BLOCKS
- they can be overwhelmed if too much agonist drug is given*
what interaction does a non competitive antagonist do?
- binds to allosteric sites and makes conformational change
- prevents neurotransmitter binding or prevents activation of the receptor
- irreversible
DISTORTS
what are partial agonists?
- binding affinity
- lower receptor efficacy than full agonist
what are inverse agonist?
- binding affinity
- initiate a biological action that is opposite to that produced by an agonist
what are allosteric modulators?
- positive modulators (PAM)
- negative modulators (NAM)
what are positive modulators?
- bind to allosteric sites
- increase the ability of a neurotransmitter to bind to and/or activate the receptor
what are negative modulators?
- bind to allosteric sites
- decrease the ability of a neurotransmitter to bind and/or activate the receptor
what are indirect agonists?
- enhances receptor activity without directly binding to receptor
how..
1. RELEASING AGENTS - more transmitter release from presynaptic neuron (ex. amphetamine)
2. REUPTAKE INHIBITORS - makes them stay in the synaptic cleft and not taken back in
3. ENZYME INHIBITORS - keeps them in synaptic cleft
4. PRESYNAPTIC REGULATOR - interact with auto/hetero receptors on presynaptic neuron