Using Research Evidence, Critically Discuss the Role of the Neurotransmitter Dopamine upon Behaviour

Running head: PSYCHOLOGY
Using Research Evidence, Critically Discuss the Role of the Neurotransmitter Dopamine
upon Behaviour
Name of the Student
Name of the University
Author Note

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PSYCHOLOGY
Introduction
Dopamine (DA) is an organic chemical compound belonging to the family of the
catecholamine and phenethylamine which play an important role in controlling mood and
behaviour (Moran et al., 2012). According to Baixauli Gallego (2017), dopamine is a
hormone which has inherent relation with happiness and regulation of the mood. When a
person feels physically attracted to another person, activation of the dopamine occurs, which
in turn leads to the increase in the level of secretion of oxytocin. Hormone oxytocin decreases
pain and increases the perception of the emotional connection and thereby helping to elevate
mood and behavioural changes (Baixauli Gallego, 2017). The below discussion is mainly
based on dopamine as a neurotransmitter in behavioural effect.
The following essay aims to critically analyse the role of the dopamine
neurotransmitter upon behaviour of individuals. In doing the critical analysis, the essay will
initiate with the basic mechanism of mechanism of dopamine, its site of expression and who
it is helpful in elevating the mode or treating the depression. On the second part of the critical
analysis, the essay will highlight the how the action of dopamine is successful in treating
several mental health complications via eliciting elevation in overall state of mind and
goodness of mood.

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PSYCHOLOGY
Figure: Tyrosine to epinephrine conversion pathway leading to the generation of dopamine as
an intermediate product
(Source: Moran et al., 2012)
Relevance and understanding
The dopaminergic receptors and their downstream signalling play an important role in
modulating the overall behaviour of individuals (Wu et al., 2012). Wu et al. (2012) are of the

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PSYCHOLOGY
opinion that DA plays an important role in controlling neuronal motor control, emotion,
cognition, vascular function and prediction of events. The effect of dopamine on the
behaviour of an individual in mainly co-ordinated by the dopamine D1 receptor (Porras et al.,
2012). It is the most abundant subtype receptor of the brain and mainly regulates via adenyl
cyclise activation followed by phosphoinositide hydrolysis along with coupling of the
heterotrimeric G protein couple receptors. D1 receptor is expressed highly in brain with
special mention to striatum, cerebral cortex, olfactory blub and to smaller extent to the
amygdale and hippocampus of the brain (Gangarossa et al., 2012). This high concentration of
the dopamine receptor (D1) in the brain further strengthens the role of dopamine in
controlling the behaviour of an individual. At cellular level, the dopamine receptors is located
at the axon terminal and dendrites which facilitates the faster transmission of the neuronal
impulses of dopamine and there promoting more prominent effect of dopamine
neurotransmitter over the behaviour. Not only the D1 receptor of dopamine, the D2 receptor
of dopamine also plays an important role in controlling and co-ordinating the behavioural
responses of an individual. The research undertaken by Gangarossa et al. (2012) highlighted
that the D2 knockout mice are more hyperactive but show poor performance in the slower
learning ability in the Morris water maze task. As per the neurophysical studies, both D1 and
D2 are highly expressed in the prefrontal cortex (PFC) and striatum of the brain (Frederick et
al., 2015). According to Warden et al. (2012) PFC is thought to participate in high level
control of behaviours like decision to execute actions. Warden et al. (2012) stated that the
defects in the PFC of the brain as evident from the magnetic resonance imaging technique
(MRI) highlighted that the lesion in the PFC lead to the defects in the proper downstream
signalling of the dopamine neurotransmitter leading to the generation of impulsive states
along with an increased tendency to initiate actions. The hamper in the downstream signalling
in the dopamine neurotransmitter also creates a-motivational states which is defined by