1. antipsychotics Flashcards
true or false: antipsychotics are mainly antagonists
true - there are some instances where they may be a partial agonist
what is the amino acid precursor of dopamine
tyrosine
what are the two types of degrading enzymes found in the dopaminergic presynaptic axon terminal?
MAO and COMT
true or false: MAO degrading enzymes can be found intracellularly and extracellularly
true
true or false: COMT degrading enzymes can be found intracellular and extracellularly
false - only extracellular
What is the purpose of the dopamine transporter (DAT) or reuptake pump?
Transport dopamine back up into presynaptic neuron from the synaptic cleft therefore regulating the amount of dopamine in the cleft
What are the three fates of DA in the presynaptic axon terminal?
- DA can be stored in vesicles inside the neuron
- If the vesicle fuses with the neurons membrane, DA can get back out into the cleft
- DA can be broken down by MAO
Where in the synaptic cleft do drugs normally target?
Dopamine transporter (DAT)
This regulates the release of dopamine from the presynaptic neuron
Presynaptic D2 receptor
This is a post synaptic DA receptor involved in psychosis, movement and prolactin regulation. All antipsychotics has an action on this receptor
D2
Clozapine is a potent antagonist of this post synaptic DA receptor
D4
What are the 4 main DA pathways in the brain
- Nigrostriatal
- Mesolimbic
- Mesocortival
- Tuberoinfundinular
What kind of symptoms occur if there is too much DA present in mesolimbic pathway
Positive symptoms (e.g. hallucinations, hearing voices)
What symptoms occur if there is too little DA in the mesocortical pathway?
dorsolateral PFC & ventromedical PFC = negative sx’s
dorsolsteral PFC = cognitive sx’s (trouble focusing, learning)
Ventromedicsl PFC = Mood symptoms (depression)
True or false: treatment goals include increasing DA in nigrostriatal and tuberoinfundibular pathways
False - these pathways should be left alone
What type of antipsychotics are the following:
Chlorpromazine, perphenazine, loxapine, zuclopenthixol, fluphenazine, trifluoperazine, haloperidol
1st generation or typical/conventional antipsychotics
What type of antipsychotics are the following:
Risperidone, quetiapine, olanzapine, paliperidone, ziprasidone, clozapine, asenapine, lurasidone.
2nd generation
What type of antipsychotics are the following:
Aripiprazole, brexpiprazole, cariprazine
3rd generation antipsychotics
First generation antipsychotics may have different affinities and potencies for blocking what four receptors?
D2, M1, H1 and alpha1
If an FGA has a high potency for blocking D2, it will have inverse affinities for blocking M1, H1 and alpha1
True
What will happen if you add a D2 antagonist when there is too much dopamine in the mesolimbic tract
Decrease positive symptoms
What will happen if you add a D2 antagonist when there is too little dopamine in the mesocortical pathway
May aggravate negative symptoms