Anti-Parkinsonian Drugs and Neuroleptics Flashcards
Describe DA synthesis
- L-tyrosine -> (tyrosine hydroxylase) ->L-DOPA -> (DOPA decarboxylase) -> Dopamine (DA)
What is the rate limiting step in DA synthesis
Tyrosine hydroxylase
What removes DA from the synapse (2)
DA transporter and NA transporter
What metabolises DA (3)
Monoamine oxidase A (MAO-A) - metabolises DA, NE & 5-HT
MAO-B - metabolises DA
Catechol-O-methyl transferase (COMT) - wide distribution (glial cell, presynaptic terminal, CM of other cells), metabolises all catecholamines
What enzymes metabolises all catecholamines
COMT
What does MAOA metabolise?
DA, NE, 5-HT
4 major dopaminergic pathways?
- Nigrostriatal pathway - susbstantia nigra pars compacta (SNc) to the striatum Inhibition results in movement disorders (Parkinsons)
- Mesolimbic pathway - ventral tegmental area (VTA) to the Nucleus Accumbens (NAcc) Brain reward pathway (Schizophrenia)
- Mesocortical pathway - VTA to the cerebrum/frontal lobe. Important in executive functions & complex behavioural patterns (Schizophrenia)
- Tuberoinfundibular pathway - arcuate nucleus to the median eminence. Inhibition results in hyperprolactinaemia
Where is Nigrostriatal pathway from/to
susbstantia nigra pars compacta (SNc) to the striatum
What does inhibition of the Nigrostriatal pathway result in
Movement disorders (Parkinsons)
Where is Mesolimbic pathway from/to
ventral tegmental area (VTA) to the Nucleus Accumbens (NAcc)
Where is mesocortical pathway from/to
VTA to the cerebrum/frontal lobe
Where is tuberoinfundibular pathway from/to
arcuate nucleus to the median eminence
What is the pathway from susbstantia nigra pars compacta (SNc) to the striatum known as
Nigrostriatal pathway
What is the pathway from arcuate nucleus to the median eminence known as
tuberoinfundibular pathway
What is the pathway from VTA to the cerebrum/frontal lobe known as
mesocortical pathway
What is the pathway from ventral tegmental area (VTA) to the Nucleus Accumbens (NAcc) known as
Mesolimbic pathway
What does inhibition of the susbstantia nigra pars compacta (SNc) pathway to the striatum lead to
Movement disorders (Parkinsons)
What does dysfunction of the Mesolimbic pathway lead to
Schizophrenia
What does dysfunction of the mesocortical pathway lead to
Schizophrenia
What does dysfunction of the tuberoinfundibular pathway lead to
hyperprolactinaemia
What does pathway dysfunction of ventral tegmental area (VTA) to the Nucleus Accumbens (NAcc) lead to
Schizophrenia
What does pathway dysfunction of VTA to the cerebrum/frontal lobe lead to
Schizophrenia
What does pathway dysfunction of susbstantia nigra pars compacta (SNc) to the striatum lead to
Parkinsons and other motor diseases
What is the Mesocortical pathway important for
executive functions & complex behavioural patterns
