Randhawa Psychopharmacology Lecture Flashcards
(192 cards)
what does pharmacokinetics describe
how an organism affects the drug
person–> drug
what does pharmacodynamics describe
how a drug affects the organism
drug–> person
what determines the effect of a drug on a person
what 5 factors determine HOW MUCH drug is delivered to its target
Liberation
Absorption
Distribution
Metabolism
Elimination
what 4 CYP enzymes/system commonly affect psychiatric medications
1A2
2D6
2C19
3A
which CYP enzyme is related to cigarette smoking
1A2
what CYP enzyme is affected by fluoxetine and paroxetine
2D6
which CYP enzyme is inhibited by grapefruit juice
3A4
what 4 factors can affect individual variability in terms of drug response
Genetics
Age
Disease
Environment
where are the primary dopamine projections
from the ventral tegmental area and substantia migra (midbrain)
where are the primary noradrenergic projections
from the locus ceruleus
in which disease is there a substantial loss of locus ceruleus cells
alzheimers
where do the serotonergic projections originate
raphe nucleus
how do TCAs and SSRIs differ with regard to their effect on voltage gated sodium channels
TCAs block the voltage gated sodium channel in nerves/neurons–> SSRIs do not
this makes TCAs more toxic in overdose but may underlie their efficacy in neuropathic pain
*venlafaxine also blocks this channel
*the voltage gated sodium channel is responsible for generation of the action potential along the neuron/cell… it is the influx of sodium that generates the action potential
upon which channel do gabapentin/pregabalin act
the voltage gated calcium channel (which controls neurotransmitter release at the synapse)
what are SNARE proteins and why do we care about them in psychiatry
are altered in SCZ and bipolar d/o
does lithium affect CYP?
no
what happens when the action potential reaches the synapse in the neuron
influx of calcium through the voltage gated calcium channels (VGCC)–> activation of synaptotagmins–> activates SNARE proteins on the cells membrane and synaptic vesicles–> causes vesicles to merge with cell membrane
*SNARE proteins are altered in SCZ and bipolar
how do botulinum and tetanus toxins work to impair cell signalling?
they cleave the SNARE proteins and prevent vesicles from being able to release neurotransmitter
what are ionotropic receptors
post synaptic receptirs that are ion channels–> a binding of a ligand to the receptor changes the receptors permeability to particular ions–> typically have multiple subunits
name two examples of post synaptic ionotropic receptors
GABA and glutamate receptors
what are metabotropic receptors
work through second messenger systems–> most MONOAMINE receptors are metabotropic
what the role of presynaptic autoreceptors and heteroreceptors
decrease the chance that a synapse will fire–> by opening potassium or chloride channels to hyperpolarize the cell and decrease the likelihood that an incoming signal/action potential will reach threshold
how do G protein coupled receptors work
G proterins have 3 subunits (alpha, beta, gamma)–> when ilgand binds the G protein breaks apart and separates from the receptor