Antipsychotics Flashcards
How do antipsychotics work?
Interfere with amine NTs because of imbalances.
Neural symptoms of Schizophrenia
Disturbance in the areas of the brain associated with thought, perception, attention, motor behavior and emotion.
Unstable moods and delusions may occur.
What causes Schizophrenia?
Imbalance of dopaminergic signalling as well as other amine NTs.
Some drugs e.g. cocaine, amphetamine, meth etc can heighten the effects of Schizophrenia because they induce dopaminergic signalling
Positive symptoms of Schizophrenia
These symptoms are frightening and consist of hallucinations (voices), delusions (paranoia), irrational/wild delusions, bizzare behaviour, including stereotyped movements, aggression, defects in attention and catatonia (comatose). More common in younger people
Negative symptoms of Schizophrenia
Blunting of emotions, withdrawal from social contacts, flattening of emotional responses, anhedonia, reluctance to perform everyday tasks.
More common in older patients.
Common symptoms of Schizophrenia
Cognitive deficits such as attention/memory, anxiety, depression, self-punishment and suicide.
Factors causing Schizophrenia
No single gene responsible. Can be hereditary as a result of abnormalities which disrupt the development of the brain.
Schizophrenic brains tend to have larger ventricles and a smaller volume of tissue in the left temporal lobe.
Drugs which enhance DA signalling increase positive symptoms.
D2 receptor signalling- blocking this decreases symptoms.
Role for glutamate (NDMA receptors).
What does dopamine do?
Implicated in many body functions- movement, attention, learning and reward reinforcement (highly associated with positive symptoms).
Primary NT pathway affected by illegal drugs
Dopamine pathways-
Nigrostriatal- motor function- is impaired in Parkinson’s disease
Mesocortical and Mesolimbic pathways- behaviours, pleasure/euphoria pathways (motivation), compulsion
Also affects pituitary hormone release and can cause vomiting and nausea as a result of its effect on the Medullary chemoreceptor trigger zone
Which dopaminergic pathway is affected in Schizophrenia
Mesocortical and Mesolimbic- affects compulsion behaviors
How is Dopamine produced?
Comes from tyrosine which is an AA. Goes to DOPA and then this gets turned into dopamine.
Dopamine is also a precursor for noradrenaline and adrenaline.
Why is it important to have very specific drug binding to the DA receptors.
Dopamine is the precursor for NorA and A- this means that their structures are very similar and so their receptors are very similar- don’t want the drugs to have an effect on the NorA and A recptors
How is Dopamine action terminated?
Reporters which take the DA back to the synapse where it is broken down my MAO and COMT.
Why do some Parkinson’s patients experience hallucinations when on their treatment.
The drugs will aim to increase the levels of DA to help alleviate the symptoms of Parkinson’s.
How do Amphetamines work?
They can be taken up into the nerve terminal by the same pathway as the DA and NorA.
They stimulate the secretion of DA and NorA, and inhibit their metabolism via inhibiting MOA and COMT.
They can also replace the DA and NorA in the vesicles and cause re-uptake transporters to work in reverse.
All leads to an increase in DA signalling.
