Mn506 System Management - Free Assessment Answers

Answer:

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.

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 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 symptoms like reduced activity hopelessness and overall decrease in mood (Warden et al., 2012).  

The influence of the dopamine on the overall behaviour of an individual is also evident from the effect of dopamine in controlling depression or other depressive symptoms. The results reported by Tye et al. (2013) highlighted that the major depression is characterised by a diverse group of debilitating symptoms which encompass anhedonia and hopelessness. The main role of the dopaminergic neurones is to motivation. This motivation creates a positive behavioural approach and thereby helping to uplift the overall behaviour of an individual. Tye et al. (2013) further highlighted that the role dopamine in controlling and elevating mood of an individual is also evident the mode of actions of the anti-depressant. The antidepressants used are to treat mood swings mainly acts via modification in the downstream signalling of the dopamine signalling pathways. The antidepressant mainly promotes bidirectional control over the dopaminergic neurons which in turn helps to relieves depression and stress (Tye et al., 2013). 

The effect of dopamine neurotransmitter on behaviour of an individual is further explained by its role in controlling the depression. According to Argyropoulos and Nutt (2013) adhedonia, a medicine which is used to treat depression, mainly works via modulating the downstream signalling pathway of dopamine. The research undertaken by McCabe et al. (2011) showed adhedonia mainly works via the manipulation of dopamine transmission at the ventral striatum and this leads to a concurrent change in the overall mood of individual.

Discussion and Critique

The roe of the dopamine in modulating the behaviour of an individual can further be explained by the effect of dopamine in extreme mood disorder disease like schizophrenia. According to Brisch et al. (2014), inhibitory neurotransmitter, dopamine is involved in the pathology of schizophrenia. Among the schizophrenia patients there occurs abnormality in the dopamine secretion in the mesolimbic and from the prefrontal brain regions. This defects in the dopamine secretion leads to hallucination, frequent change in mood and thereby causing an overall change in the behaviour of an individual. Brisch et al. (2014) highlighted that the receptors of dopamine are G-protein coupled receptors whose expression are decreased in the PFC of the brain of the schizophrenia patients leading to frequent mood swings. Wu et al. (2012) highlighted that dysfunctional dopaminergic system in children with ADHD. This is one of the reasons behind their frequent mood fluctuations and hyperactivity. On discussing, the role of the dopamine in Parkinson’s disease Dirkx et al. (2017) highlighted that proper dosage of dopamine helps to control tremor common in the Parkinson’s disease. However, tremor is not directly related to the change in the mood or behavior but Segura?Aguilar et al. (2014) are of the opinion that there is certain relation of the tremor in the mood disorder. For example, tremor is classified as form of neurological defects and this neurologic defects cause irritation results in behavioral orders.

However, in relation to dopamine and its relation to behaviour of an individual, Brisch et al. (2014) are of the opinion the apart from dopamine, GABA (gamma- amino butyric acid), acetylcholine and serotonin also plays an important role in regulating the behaviour or mod of an individual. It is the effective interplay of serotonin, GABA, dopamine and acetylcholine that complete co-ordination of the mood of an individual occurs. Brisch et al. (2014) further stated that serotonin receptors plays more prominent role in controlling the behaviour of an individual. Mahar et al. (2014) presented a completely different opinion in the behavioural control. According to them, it is the serotonin which plays a critical role in controlling the mood swings and the behavioural problems. Chronic stressful life events are the major risk factors for the development of depression and its pathophysiology is inherently linked with the impairment of the serotonin neurotransmission. Lack of proper serotonin secretion leads to the generation of the depressive behaviours and this in turn leads to mood swings.  Here comes the importance of the selective serotonin reuptake inhibitors (SSRI) which are one of the most popular antidepressants. SSRIs reduce the chronicity of depression via increase the level of secretion of serotonin in the brain. SSRIs mainly block the re-absorption or reuptake or serotonin in the brain and thereby making serotonin available in the body fluid. This promotes the downstream signalling of the serotonin and thereby reducing the state of depression. SSRIs are mainly called selective because they specifically effect on the serotonin and not other inhibitors. Serotonin also helps in the treatment of other mood disorders like anxiety (Mead et al., 2013).

Conclusion

Thus from the above discussion, it can be concluded that dopamine plays an important role in control and co-ordination of mood and behaviour of individuals. This control of dopamine over behaviour is mainly achieved expression of the dopamine in brain, expression of the G-protein coupled receptor of dopamine and proper downstream signalling of dopamine neurotransmitter. The role of dopamine on behaviour control is mainly exhibited the effect of dopamine in controlling depression and mood swings. Moreover, several studies have highlighted that the complex mood disorders like the AHDH, schizophrenia and Parkinson’s show significant malfunction in the dopamine expression and signalling. On contrary other studies are of the opinion that it is serotonin which plays a pivotal role mood, depression and depression control. However, it can further be said that the overall control of behaviour of an individual is not solely dependent on dopamine expression but is also dependent on the active control and co-ordination of serotonin, GABA acetylcholine and dopamine.

References

Argyropoulos, S. V., & Nutt, D. J. (2013). Anhedonia revisited: is there a role for dopamine-targeting drugs for depression?. Journal of Psychopharmacology, 27(10), 869-877.

Baixauli Gallego, E. (2017). Happiness: role of dopamine and serotonin on mood and negative emotions. Emergency Medicine (Los Angeles), 2017, vol. 6, num. 2, p. 33-51.

Brisch, R., Saniotis, A., Wolf, R., Bielau, H., Bernstein, H. G., Steiner, J., ... & Henneberg, M. (2014). The role of dopamine in schizophrenia from a neurobiological and evolutionary perspective: old fashioned, but still in vogue. Frontiers in psychiatry, 5, 47.

Dirkx, M. F., den Ouden, H. E., Aarts, E., Timmer, M. H., Bloem, B. R., Toni, I., & Helmich, R. C. (2017). Dopamine controls Parkinson’s tremor by inhibiting the cerebellar thalamus. Brain, 140(3), 721-734.

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Gangarossa, G., Longueville, S., De Bundel, D., Perroy, J., Hervé, D., Girault, J. A., & Valjent, E. (2012). Characterization of dopamine D1 and D2 receptor?expressing neurons in the mouse hippocampus. Hippocampus, 22(12), 2199-2207.

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Mead, G. E., Hsieh, C. F., Lee, R., Kutlubaev, M. A., Claxton, A., Hankey, G. J., & Hacklett, M. L. (2013). Selective serotonin reuptake inhibitors (SSRIs) for stroke recovery. Sao Paulo Medical Journal, 131(3), 208-209.

Moran, L. A., Horton, H. R., Scrimgeour, K. G., & Perry, M. D. (2012). Principles of biochemistry (pp. 433-435). Boston: Pearson.

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Segura?Aguilar, J., Paris, I., Muñoz, P., Ferrari, E., Zecca, L., & Zucca, F. A. (2014). Protective and toxic roles of dopamine in Parkinson's disease. Journal of neurochemistry, 129(6), 898-915.

Tye, K. M., Mirzabekov, J. J., Warden, M. R., Ferenczi, E. A., Tsai, H. C., Finkelstein, J., ... & Gunaydin, L. A. (2013). Dopamine neurons modulate neural encoding and expression of depression-related behaviour. Nature, 493(7433), 537.

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Wu, J., Xiao, H., Sun, H., Zou, L., & Zhu, L. Q. (2012). Role of dopamine receptors in ADHD: a systematic meta-analysis. Molecular neurobiology, 45(3), 605-620.