fundamental neuropharmacology Flashcards
what is neuropharmacology?
the study of drugs that affect the NS and how they affect the NS.
what aspects of the NS do drugs effect?
sensory perception,
motor function,
seizure activity,
mood,
higher cognitive function,
what is picrotoxin?
a non-competitive GABA-A receptor antagonist.
what is tetratoxin (TTX)?
a potent neurotoxin that is poisonous to humans.
what can TTX be treated with?
a neostigmine
what are symptoms of TTX poisoning?
paralysis,
muscle weakness,
bradycardia,
cardiac arrest.
what is d-tubocurarine?
an alkaloid,
and an antagonist of acetylcholine.
which type of plant, often used to make spears, contains d-tubocurarine?
curare vine - liana.
what is novichok, what does it affect, and what does it cause?
a nerve agent.
inhibits acetylcholinesterase.
causes spasms, prevents relaxation of muscles (cardiac and respiratory).
very fast acting.
what did the leech test find?
that
NT criteria:
NT’s must be …
synthesised and released from neurons.
NT criteria:
NT should be released from nerve terminals in a …
… chemically or pharmacologically identifiable form.
NT criteria:
A NT should reproduce …
… at the postsynaptic cell the specific events that are seen after stimulation at the presynaptic neuron.
NT criteria:
Effects of NT should be blocked …
… by competitive antagonists of the receptor for that transmitter in a dose-dependent manner.
what are the 2 classes of receptors?
- ionotropic.
- metabotropic or G-protein coupled.
what is a ligand?
any chemical that binds/combines with a receptor.
what is a receptor?
a cellular macromol/mols that is concerned in chemical signalling between and within cells.
what type of process is the binding of ligands and receptors?
an active process.
what are endogenous ligands?
ligands that are naturally produced by the body.
what are exogenous ligands?
endogenous ligands that are modified or designed by chemists.
what were radioligands binding assays used for?
they were used to quantify the amount of ligand bound to receptors.
what is non-specific binding?
binding in a place other than the binding site that it under investigation.
it is unsaturable.
how can specific binding be calculated?
by calculating the difference between total and nonspecific binding.
what does specific binding in a radioligand assay reflect?
it reflects the amount of radioligand bound to specific binding site.
what is total binding?
the total binding observed - specific and non-specific.
what shape would non-specific binding be on a graph? why?
linear - because its constantly happening.
what shape would specific binding be on a graph? why?
curve then levels out - happens as max is eventually reached.
Bmax
maximum saturated binding which is achievable.
kd
dissociation constant = the affinity of binding that results in 50% of maximal binding (Bmax).
what are the 2 types of ligands?
agonist,
antagonist.
what does an agonist do?
produces effects in bio tissues
what are the 3 types of agonists and what effects do they have?
full = produce max effect.
partial = effect but not maximal.
inverse = produces effects that are opposite from the original. can be partial or full.
what do antagonists do?
they prevent the effect of an agonist but have no effect themselves.
what are the 2 types of antagonists?
competitive and non-competitive.
what do competitive antagonists do?
compete with the agonist for the same binding site on the receptor.
do competitive antagonists effect the efficacy of the agonist? why?
no, they do not as the same number of receptors are available to both.
what do non-competitive antagonists do?
they bind to a different binding site and alter the configuration of the receptors for agonists so they can’t bind.
do non-competitive antagonists effect the efficacy of agonists?
yes they do as they reduce the number of receptors available for agonists to bind to.
what happens when agonists are repeatedly used?
desensitisation.
what can partial agonists act as? how do they do this?
as a functional antagonist because when they are in the presence of a full agonist, it reduces the ability of the full agonist to produce maximal effects.
what does efficacy mean?
the ability of a drug to produce a max response of effect when binding.
what does potency mean?
the amount of drug needed to produce a certain effect.
Emax
maximal response that drugs produce.
EC50
effective concentration in vivo.
ED50
the does needed to produce 50% max response.
what do psychotropic drugs do?
they influence behaviour
what is pharmacodynamics?
the study of drugs that looks at what the drug does to the body - the time course of its effects the intensity of them.
what is pharmacokinetics?
the study of what the body does to a drug - how it is absorbed, metabolised, etc.
movements of drugs in the body.
what is bioavailability?
the ability of a drug to produce an effect of an organism is dependent on many properties
what are the 6 stages of pharmocokinetics?
- route of administration.
- release/liberation.
- absorption.
- distribution (dosing regiments).
- metabolism (metabolite kinetics, clearance).
- excretion (clearance).
what are the 3 most popular routes of administration?
oral, intravenous, subcutaneous.
what is the bioavailability of a drug affected by?
by the absorption of a drug.
by metabolism and excretion.
Cmax
peak plasma conc of drug after administration.
tmax = time to reach Cmax.
what are the 3 fundamentals of clearance?
- vol of distribution.
- clearance.
- elimination half-life.
