- Human behaviour, dopamine and DNA
- Dopamine acts as a NEUROTRANSMITTER and a HORMONE.
- It is a precursor molecule in production of ADRENALINE & NORADRENALINE.
- Abnormally LOW levels of dopamine are associated with Parkinson's disease.
- HIGH levels of dopamine resulting from treatment/occurring naturally have been linked to mental health conditions such as Schizophrenia.
- Dopamine increases general AROUSAL and decreases INHIBITION, leading to an increase in creativity in conjunction with cerebral activity.
- There are 5 different dopamine RECEPTORS referred to as DRD1 to DRD5. Each of these is coded for by a separate GENE.
- BINDING of dopamine to its receptors is involved in motivation and leaning and linked to regulatory effects on other neurotransmitter release.
- A number of ANTIPSYCHOTIC DRUGS work by BLOCKING dopamine receptors.
- The DRD4 receptor gene:
- Studies have shown variants of the DRD4 gene affect the level and action of dopamine in the brain.
- Drugs e.g. RITALIN used to treat ADHD affect dopamine levels in brain. One variant of DRD4 shown to be more frequent in individuals with ADHD.
- Variants pf DRD4 cause increased likelihood of addictive behaviours e.g. smoking and gambling. Becomes a difference in risk taking and arousal.
- Other neurotransmitter-influenced behavioural conditions:
- Obsessive-compulsive disorder (OCD) is thought to result from a deficiency in levels of neurotransmitter SEROTONIN.
- Contributes to the nature-nurture debate. Behaviour cannot be attributed to either genes or the environment, it is a product of both.
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