PBL 8 Flashcards
What are the 4 main dopamine pathways?
Where to they project from and to?
Nigrostriatal - substantia nigra to striatum of basal ganglia
Mesolimbic - VTA to nucleus amcubens
Mesocortical - VTA to dorsolateral prefrontalcortex
Tuberoinfundibular - tuberal region to infundibular region (pituitary stalk)
What is the action of dopamine on the tuberoinfundibular pathway?
Inhibits prolactin release from the pituitary gland
Which dopamine receptors are in the D1 and D2 receptor families?
D1: D1, D5
D2: D2, D3, D4
What are the two types of schizophrenia?
Paranoid schizophrenia - dominated by delusions and hallucinations
Residual schizophrenia - predominantly negative symptoms
What are some examples of delusions in the positive symptoms of schizophrenia?
Reference - think people are always talking about me
Persecution - people mean me harm
Control - I am under control from outside spirit
Grandiosity - I am a genius
Hypochondriacal - there is an insect under my skin
What are positive symptoms in schizophrenia?
Delusions
Hallucinations
Thought disorder
Catatonic behaviour
What are the 3 categories of symptoms in schizophrenia?
Positive
Negative
Cognitive
What is the difference in prevalence in schizophrenia between men and women?
Slightly higher prevalence in men
Age of onset in men is earlier (12-25)
Age of onset in women is later (20-30)
Men have a poorer response to treatment
What are the 1st rank symptoms for diagnosing schizophrenia?
Thought echo/insertion/broadcasting
Delusions of control
Auditory hallucinations
Persistent delusions
What are the 3 phases of schizophrenia?
Prodromal - patient becomes withdrawn
Active - severe positive symptoms occur
Residual - patients show cognitive symptoms
What is alogia
Poverty of speech/lack of content in speech
What is avolition?
Decrease in motivation
What are the dopamine abnormalities seen in schizophrenia?
Excessive dopamine in the associative striatum in the nigostriatal pathway
Inadequate dopamine in the prefrontal cortex and ventral striatum
What is the glutamate-dopamine hypothesis of schizophrenia?
- Hypo-functional glutamate NMDA receptor present on GABA interneurons
- GABA release is low and cannot suppress glutamate outflow from the cortex
- excessive glutamate stimulation of substantia nigra pars compacta
- direct stimulation of sensorimotor and associative striatum leads to an increase in dopamine release
- indirect inhibition of VTA via GABA interneuron - leads to a decrease in dopamine in the cortex
How is hyperprolactinemia caused and what are the symptoms?
Increased production of prolactin due to D2 receptor blockage: leads to decreased dopamine which usually inhibits prolactin release
- sexual dysfunction (decreased arousal)
- breast pathology
- hypogondism (decreased BMD) leading to hip fractures
- ache
- excessive hair growth
