Question

Discuss the role of dopamine in psychotic alterations. How does the role of first-generation and second-generation antipsychotics differ? Please provide an example of at least one of each type and discuss its mechanism of action.

Answer 1

Role of Dopamine in Psychotic alterations:

• Dopamine also called as hydroxytyramine.
• It plays a role in daily behavior.
• It is a precursor for hormones epinephrine and norepinephrine.
• It acts as a chemical messenger called neurotransmitters which inhibit the transmission of nerve impulses such as basal ganglia, substantia nigra, corpus striatum.
• In the absence of neurotransmitter, dopamine-receptor antagonist increases the dopaminergic activity.
• If any abnormalities in the dopamine transmission result in psychotic alterations of altered behavior.
• It affects the mood and loss of interest in activities of eating, drinking.

How does the role of first-generation and second-generation antipsychotics differ?

First generation antipsychotic	Second generation antipsychotic
Typical antipsychotics	Atypical antipsychotics
Used to treat hallucinations and delusions.	Used to treat schizophrenia.
Also called as conventional antipsychotics.	The drugs are also known as dopamine- serotonin antagonist.
It is D2 antagonist act on the mesolimbic, mesocortical, tuberoinfundibular pathways.	It acts by block D2 receptor and 5HT2A receptors.
It is associated with a high risk of EPS.	It is associated with low risk of EPS.
Higher generation of neurological side effects.	Higher risk of metabolic side effects.
Examples are Chloropromazine, Haloperidol, Loxapine.	Examples are Clozapine, Olanzapine, Lurazidone.