psychopharmacology Flashcards
what is a drug
an exogenous chemical
they work by altering certain functions
what is an Agonist drug
Facilitate or mimic action of a NT
so facilitates postsynaptic effects
what is an antagonist drug
inhibit action of a NT so it blocks postsynaptic effects
Mechanics of drug action- how drugs affect synthesis
-without synthesis it cannot be released
Drugs can alter synthesis of NT inside the presynaptic neuron
-it does this by modifying the concentration of NT in the synaptic cleft
- drugs cause a lack of synthesis which reduces Nt concentration
It can be antagonist- inactivate enzymes
it can be agonist- introduce precursor molecules
mechanics of drug action- storage
vesicles are needed and stored
drugs can alter NT storage in presynaptic membrane
- it does this by modifying concentration in the synaptic cleft
- this means vesicles remain empty/ they don’t contain NT
mechanics of drug action- release
drugs change NT release from presynaptic cell- by modifying conc in synaptic cleft
antagonist- prevent release
agonist- trigger NT release
mechanics of drug action - receptors
drugs act on receptors
they modify post synaptic potentials
agonists open ion channels
antagonists block NT causing ion channels to remain closed
mechanics of drug action- reuptake
drugs modifies removal of NT from synaptic cleft by changing conc in the synaptic cleft.
agonist= reduce or block reuptake
mechanics of drug action- destruction
drugs modifies destruction
Agonist= enzymes typically inactivate NT
what is tolerance
effects of drugs diminish
This can be because cell receptors in the body that become active when the drug binds to them stop responding or your body clears the drug at a higher rate. If the user stops taking the drug they would experience withdrawal symptoms.
cell receptors stop resonding
body clears drugs at a higher rate
What is sensitisation?
Drugs become more and more effective the more it is prescribed- this can occur after neurogenic inflammation when neurones become more responsive to painful and not painful stimuli. This can happen with the major drugs such as cocaine and heroin.
What produces withdrawal symptoms?
compensatory mechanisms that produce the opposite reaction to the drug e.g. agitation instead of relaxation
for example down regulation/ process that couples the receptor to ion channels in the membrane or to the production of second messengers
after prolonged stimulation of the receptors one or more steps on the coupling process become less effective
What is the main toxic effects of opioid use?
respiration difficulties due to the drug depressing neurons in the medulla responsible for HR and respiration
what is a treatment for opioids?
Naloxone
it wokrs as an opioid antagonist by binidng to the opioid receptors like opiate drugs- this enables them to push off any existing opioid off the receptors. This stops opioids causing toxic effects as they can no longer access the receptors.
