name the first antipsychotic… when was it introduced
chlorpromazine –> 1955
*antipsychotics considered the single greatest advance in the treatment of mental disorders
names of the psychiatrists who introduced chlorpromazine as the first antipsychotic
pierre deniker
jean delay
*french
what dopaminergic pathway to antipsychotics target to treat the positive symptoms of schizophrenia
mesolimbic
list the 4 key dopaminergic pathways that antipsychotics affect
mesocortical
mesolimbic
nigrostriatal
tuberoinfundibular
what areas does the mesocortical pathway connect
prefrontal cortex
to the
ventral tegmental areas
what areas does the mesolimbic pathway connect
nucleus accumbens
to the
ventral tegmental area
what areas does the nigrostriatal pathway connect
substantia nigra
to the
basal ganglia (striatum)
what areas does the tuberoinfundibular pathway connect
hypothalamus–arcuate (infundibular) nucleus
to the
hypothalamus–median eminence
why do we care about the MESOCORTICAL pathway in schizophrenia
DECREASED dopamine leads to NEGATIVE SYMPTOMS
cognitive symptoms are also thought to be due to a HYPOACTIVE mesocortical pathway
why do we care about the MESOLIMBIC pathway in schizophrenia
INCREASED dopamine leading to POSITIVE symptoms
**same pathway for nicotie-reward
why do we care about the NIGROSTRIATAL pathway in schizophrenia
also gets blocked by antipsychotics leading to EPS and akathesia
why do we care about the TUBEROINFUNDIBULAR pathway in schizophrenia
the decrease of dopamine in this pathway (thru use of antipsychotics) can cause elevated PROLACTIN
what is the regular role of dopamine in the tuberoinfundibular pathway
to tonically inhibit prolactin release
where is the tuberoinfundibular pathway found
entirely in the hypothalamus
what is the physiologic action of the normal mesolimbic pathway
motivation
emotion
reward
what is the physiologic action of the normal mesocortical pathway
cognition and executive function (dorsolateral PFC)
emotion and affect (ventromedial PFC)
the nigrostriatal system contains what % of the brains dopamine
about 80%
what two structures make up the striatum
caudate and putamen
what is the physiologic action of the normal nigrostriatal pathway
motor planning
(dopaminergic neurons stimulate purposeful movement)
the therapeutic action of an antipsychotic occurs when what % of brain dopamine (D2) receptors are occupied
65-85%
what happens when more than 80% of D2 receptors are occupied
hyperprolactinemia
parkinsonism
*CAN happn
what factors influence the likelihood of a patient experiencing EPS (or other side effects)
% receptor occupancy + amount of time the antipsychotic remains bound to the receptor
does serum level of antipsychotics correlate to brain receptor occupancy?
no–> due to the blood brain barrier
name an antipsychotic that remains bound to D2 receptors for quite a long time?
name two antipsychotics that are bound to D2 receptors for only a very short time
haldol–> bound for about 38 min
clozapine, quetiapine–> bound for about 15 seconds (“kiss and run hypothesis”)
*suggested reason for why haldol has more EPS than clozapine and quetiapine