hdac inhibitors br Discussion Personality develops throughou
Discussion Personality develops throughout a human's life and is related to his or her innate temperament. While personality features are shaped by various experiences of daily life and moderate a wide range of specific behaviours related to particular situational contexts, temperament reveals itself in the overall picture of human behaviour and plays an important role in the regulation of emotional tension (Strelau, 2008). The athletes and students in the groups studied differed significantly with regard to intensity of three temperamental traits. The scores obtained by athletes point to lower sensitivity and greater endurance of the central nervous system. These traits facilitate the control of ineffective thoughts and behaviours, while the nervous system is more resilient to external and internal stimulation, including stimuli such as fatigue and discomfort. We may expect, therefore, that compared to the control group athletes fare much better in coping with tension, physical discomfort and pressure of time. High endurance of the nervous system is a fundamental feature of professional athletes, closely related to strategies of managing mental pressure. Combat athletes are characterized by greater flexibility of behaviours and easiness in shifting attention to various sources of stimulation. This trait helps individuals to mentally free themselves from a problem and cope with difficult situations in a constructive way. The high level of perseveration is correlated with intensified trauma symptoms (Rzeszutek, Oniszczenko, Schier, Biernat-Kałuża, & Gasik, 2016). Since temperament is genetically determined we have decided to consider the association of temperamental traits with the genes encoding the proteins responsible for proper functioning of the nervous system: COMT and OPRM1. COMT is one of several hdac inhibitors which degrade catecholamines in the brain, such as dopamine, epinephrine and norepinephrine (Grossman, Emanuel, & Budarf, 1992). The COMT gene plays an important role in encoding the Catechol-O-methyltransferase enzymes (Chen et al., 2004). It has been proven that carriers of rs4680 Val (G) allele showed increased COMT activity and lower prefrontal extracellular dopamine compared with carriers of the Met (A) allele (Chen et al., 2004). Since COMT is a key enzyme in the elimination of dopamine in the prefrontal cortex (Chen et al., 2004) and the latter is of high importance to human personality (DeYoung et al., 2010). The regulation of COMT enzyme activity depends partially on the COMT gene polymorphism which involves a valine (GTG or Val) to methionine (ATG or Met) mutation at codon 108S-COMT or at codon 158MB-COMT (Lachman et al., 1996). COMT enzyme activity has been reported to be higher in Val/Val homozygotes than in Met/Met homozygotes (Chen et al., 2004), while heterozygotes showed medium enzyme activity (Weinshilboum, Otterness, & Szumlanski, 1999). The role of COMT in dopamine catabolic processes in the prefrontal cortex (PFC) gives grounds to associate it with cognitive and emotional processes (Lachman et al., 1996). Studies on the Val158Met COMT polymorphism have provided incoherent evidence for the association of this SNP with anxiety disorders. A meta-analysis of eight clinical trials has shown that the risk of obsessive-compulsive disorders is higher in male carriers of the Met allele. In a meta-analysis of COMT polymorphisms and panic disorder (PD) on a six-digit sample of Caucasians and Asians, Zintzaras and Sakelaridis (2007) did not find any associations. No statistically significant differences related to gender or ethnic group were observed either. However, using the same set of studies, Domschke, Deckert, O'Donovan, and Glatt (2007) concluded that the Val allele is associated with higher PD risk in Caucasian women, but lower PD risk in Asian women. No association between COMT val158met polymorphism and PD in men was found. Latest research assessing the impact of the COMT genotype on symptoms in Caucasian PD patients during cognitive-behavioural treatment demonstrated that Val carriers (Val/Val or Val/Met) showed more symptoms of anxiety and depression than homozygotes (Lonsdorf et al., 2010). These results are consistent with previous research, linking the Met/Met genotype with difficulties in extinguishing a conditioned fear (Lonsdorf et al., 2009). Some researchers focused on the possible correlation between single nucleotide polymorphism (SNP) and personality (Calati et al., 2011), measured with various questionnaires (Baeken, Claes, & De Raedt, 2014). A summary of research on associations between COMT rs4680 and personality traits measured by the Neuroticism-Extraversion-Openness Five-Factor Inventory (NEO-FFI) yielded inconclusive results (Lee & Prescott, 2014).