Antipsychotics - Physio and Pathophys Flashcards
What are the 4 Dopaminergic Tracts?
Mesolimbic
Mesocortical
Nigrostriatal
Tuberoinfundibular
Describe the normal Mesolimbic System
DA neurons project from ventral tegmental area to subcortical structures (ex: nuc accumbens)
Symptoms of mesolimbic system involve?
Source of psychosis (hallucinations, delusions) -mesolimbic dopamine hyperactivity
Describe the normal Mesocortical system
DA neurons project from ventral tegmental area to frontal cortex
Describe the normal nigrostriatal system
DA neurons project from substantia nigra (pars compacta) to striatum
Describe the normal tuberoinfundibular system
DA neurons projecting from hypothalamus to anterior pituitary
Blockade of D2 receptors in what dopamine tract may worsen the negative symptoms of Schizo?
Mesocortical System
Blockade of D2 receptors in what dopamine tract may lead to EPS (extrapyramidal side effects)?
Nigrostriatal system
Blockade of D2 receptors in what dopamine tract may lead to hyperprolactinemia?
Tuberoinfundibular System
Blockade of D2 receptors in the nigrostriatal system may lead to?
EPS (extrapyramidal side effects)
Blockade of D2 receptors in the tuberoinfundibular system may lead to?
Hyperprolactinemia
Blockade of D2 receptors in the mesocortical system may lead to?
Schizo NEGATIVE symptoms (mainly) due to mesocortical DA dysfunction
Describe the dopamine hypothesis.
Increased activity of DA neurotransmitter pathways (and DA receptors) is seen in Schizo
What are 4 pieces of evidence for the DA hypothesis?
- Antipsychotics block DA receptors
- Drugs that inc DA activity give psychosis (cocaine, amphetamines, levodopa)
- Inc DA receptors seen in schizo
- Treated schizo patients have dec DA breakdown products
What are limitations of the DA hypothesis?
FGAs are more effective against schizo positive symptoms (vs negative)
Some fail to respond to antipsychotics
Some treated with anti-psychotics relapse
