The role of neurotransmitters on aggression

Topics: Dopamine, Serotonin, Neurotransmitter Pages: 9 (1650 words) Published: May 30, 2014


NEUROTRANSMITTERS AND AGGRESSION
LARISSA BATISTA
PSY 407

SUMMARY
According to various scientific research studies conducted over the past three decades suggest that central neurotransmitters play a key role in the modulation of aggression in all mammalian species including humans. Specific neurotransmitters systems involved in aggression include serotonin, dopamine, norepinephrine, GABA, and neuropeptides such as vasopressin and oxytocin. Neurotransmitters not only help to execute basic behavioral components but also serve to modulate these preexisting behavioral states by amplifying or reducing their effects (Clinical Neuroscience Research Unit, 2011) THE BIOLOGY AND GENETICS OF AGGRESSION

Aggression is a form of behavior with the goal of causing damage to another individual. Evolutionarily it developed in response to competition for mates or vital resources. In humans aggressive behavior has become more nuanced, but its goals and causes are essentially the same. A genetic basis for aggression is shown in animals by the ability to selectively breed aggressive behavior to produce extremely aggressive strains in individuals. In humans, twin studies have also made clear that aggression has a strong genetic component. The role of the hormone testosterone is certainly involved, although the exact pathways are unclear. Brain levels of the neurotoxin serotonin correlate with aggression, and genetic manipulation of these levels can enhance or reduce aggressive behavior. A role for the neurotransmitter nitrous oxide has been demonstrated to influence aggression in both animals and humans (William R. Clark and Michael Grunstein 2014). Other than maternal aggression, most aggressive encounters among human and non-human animals represent a male proclivity; thus, studies using the most appropriate murine model: testosterone-dependent offensive inter-male aggression, which is typically measured in resident-intruder or isolation-induced aggression tests. The research emphasizes various molecules that have been linked to aggression tests. It also emphasizes various molecules that have been linked to aggression by the latest gene-targeting and pharmacological techniques. Although the evidence continues to point to androgens and serotonin (5-HT) as major hormonal and neurotransmitter factors in aggressive behavior, recent work with GABA, dopamine, vasopressin, and other factors, such as nitric oxide, has revealed significant interactions with the neural circuitry underlying aggression. SEROTONIN KEEPS AGRESSION IN CHECK

Many people think of serotonin as nature’s “feel-good” chemical. The most widely distributed—and most widely studied—neurotransmitter in the brain; serotonin regulates a vast range of psychological and biological functions, including mood, sleep, arousal and appetite. Now, researchers at Cambridge University and UCLA have found that serotonin also plays a critical role in regulating emotions such as impulsive aggression during social decision making. Impulsive aggression is the tendency to respond with hostility or aggression when faced with serious frustration. The researchers believe their results suggest that serotonin plays a critical role in social decision making by normally keeping aggressive social responses in check. By manipulating diet, the researchers were able to lower serotonin levels in the brains of healthy volunteers. Tryptophan, the essential amino acid necessary for the body to produce serotonin, can be obtained only through diet. When someone is given a drink containing amino acids other than tryptophan, the liver pulls tryptophan from the blood to make the protein with the new amino acid the person was just given. This process causes a drop in blood tryptophan levels to about 10 percent to 20 percent of what they are normally, leading to a reduction in the amount of newly made serotonin and, thus, a decrease in serotonin...

References: Clinical Neuroscience Research Unit (2011) , Department of Psychiatry, The University of Chicago Pritzker School of Medicine. Retrieved April 9, 2014, from http://www.ncbi.nlm.nih.gov/pubmed/22078480
William R. Clark and Michael Grunstein (2014) The Generics of aggression. Retrieved from http://oxfordindex.oup.com/view/10.1093/acprof:oso/9780195178005.003.0009
BBC News Wales (2011) Cardiff University on brain chemistry and aggression, Retrieved from
http://www.bbc.co.uk/news/uk-wales-14467942
Dongju Seo, Christopher J. Patrick, and Patrick J. Kennealy (2008), Role of Serotonin and Dopamine System Interactions in the Neurobiology of Impulsive Aggression and its Comorbidity with other Clinical Disorders. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612120/
Haden, Sara Chiara (2008, October 26). Norepinephrine and Aggression. SciTopics. Retrieved April 15, 2014, from http://www.scitopics.com/Norepinephrine_and_Aggression.html
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