اکسی توسین پاسخ های کورتیزول نسبت به استرس در افراد با توانایی های تنظیم اختلال احساسات را بافر می کند
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|38833||2011||7 صفحه PDF||سفارش دهید||5415 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Psychoneuroendocrinology, Volume 36, Issue 6, July 2011, Pages 898–904
Summary Oxytocin facilitates stress regulation but little is known about individual differences in this effect. The present study investigates whether the effect of intranasal oxytocin on stress-contingent cortisol release differs between individuals with high vs. low emotional regulation abilities (ERA). In a double-blind study thirty-six healthy male students with either high or low ERA were randomly assigned to receive intranasally 24 IU oxytocin or placebo. Cortisol was measured at several times before and after a social stressor (public speaking). Individuals with impaired ERA showed a reduced cortisol response to stress after oxytocin but an increased cortisol response after placebo application. The results suggest that healthy individuals with low ERA benefit from intranasal oxytocin application. Neurobiological mechanisms potentially underlying the link between oxytocin, cortsiol and ERA are discussed against the background of a neuroendocrinological perspective on personality.
Introduction Healthy individuals typically differ in the degree to which they are able to regulate their emotions and thus to cope with stressful events (e.g., Kuhl, 1981, Lazarus and Folkman, 1984, Gross and John, 2003 and Koole, 2009). Notably, individuals with reduced abilities to regulate their emotions are at higher risk to develop psychopathologies such as depression or anxiety disorders (Aldao et al., 2010). In the present work, we were interested in the neuroendocrinological mechanisms that may differentiate between individuals with efficient vs. inefficient ERA. Specifically, we examined whether application of intranasal oxytocin would dampen cortisol increases to a psychological stressor in individuals with reduced ERA. Such evidence would have relevance for the treatment of (a) subclinical individuals in chronic stress periods to prevent the development of psychopathological disorders and (b) manifest clinical disorders. The hypothalamus–pituitary–adrenocortical (HPA) system is typically aroused as a reaction to psychological stressors (Dickerson and Kemeny, 2004). Research conducted over the past 15 years or so has demonstrated that cortisol responses to stress vary with personality traits that are linked to abilities to regulate emotions and to cope with stress (Kudielka et al., 2009, for a review). As such, pronounced cortisol increases have been found in individuals low in self-esteem (Pruessner et al., 1999), low in subjective controllability beliefs (Pruessner et al., 1999), or high in attachment anxiety (Quirin et al., 2008). Past research has demonstrated that the neuropeptide oxytocin produced in the hypothalamus and stored in the posterior pituitary (Buijs et al., 1983) counteracts stress-induced activity of the autonomous nervous system (for research using animals, see overviews by Argiolas and Gessa, 1991 and Petersson, 2002; for humans, see Light et al., 2000) and the HPA system (for animals, e.g., Windle et al., 1997, Uvnäs-Moberg, 1998 and Neumann et al., 2000; for humans, see Heinrichs et al., 2003 and Ditzen et al., 2009). With respect to HPA regulation in humans, it has been demonstrated that intranasal oxytocin predicts reduced cortisol levels after experimentally induced couple conflicts (Ditzen et al., 2009). In this study, oxytocin also increased the amount of positive communication during the conflictive situation, a finding that acquiesces in the literature that oxytocin has positive effects on social cognition and behavior in general (Bartz and Hollander, 2006, Heinrichs and Domes, 2008 and Kosfeld et al., 2005). Heinrichs et al. (2003) manipulated oxytocin and social support and measured cortisol changes over the course of the Trier Social Stress Test (TSST; Kirschbaum et al., 1993), a demanding public speaking task. The authors found that participants receiving intranasal oxytocin in combination with social support showed the lowest increases in both cortisol and reported anxiety (Heinrichs et al., 2003). However, it should be noted that other research did not find main effects of oxytocin on cortisol responses to speech tasks on cortisol (Taylor et al., 2006) or cardiovascular reactivity (Light et al., 2005). Individual differences in oxytocin plasma levels have been investigated only recently. Specifically, reduced oxytocin plasma levels have been found in individuals with severe symptoms of generalized social anxiety disorder (Hoge et al., 2008), schizophrenic patients with emotional deficits (Goldman et al., 2008), or even in healthy individuals with high as compared to low levels of attachment anxiety (Tops et al., 2007). Intranasal oxytocin application has recently been demonstrated to facilitate social behavior and feelings of trust in autistic individuals (Andaria et al., 2010). As far as we know, it has not yet been investigated whether the effect of oxytocin on HPA system reactivity to stressors varies with individual differences in ERA in healthy individuals. Whereas emotion regulation processes can be classified at a phenotype level with respect to various strategies employed (e.g., suppression, repression, intellectualization, actionism, aggressive enactment, communication, reappraisal, and self-reflection), at a functional level, they may be classified with respect to low vs. high ERA (Kuhl, 1994b). Low ERA individuals show impairments in downregulating negative affect as aroused by threatening experiences, and, as a consequence, tend to ruminate about these experiences long after. By contrast, high ERA individuals typically are able to downregulate stress and concomitant negative emotions effectively and sustainably, and thus remain functioning and pursue goals in daily life. It has been argued that whereas individuals with low ERA depend on social support to cope with stress, individuals with high ERA are typically able to reduce stress on their own (Koole et al., 2005). Accordingly, individuals with low ERA as expressed by a tendency to ruminate about negative experiences indeed seek and benefit more from social support after a traumatic stressor than those with high ERA (Nolen-Hoeksema and Davis, 1999). If oxytocin plays a mediating role between social support and stress regulation (Heinrichs et al., 2003), we expect that individuals with low ERA would benefit more from oxytocin administration than individuals with high ERA. Notably, previous research has demonstrated that individual differences in ERA can be distinguished from individual differences in emotion sensitivity (“stress reactivity”). Whereas the former refer to the ability to manage stressful situations and concomitant negative affect once present (exit gradient), the latter refers to the sensitivity with which an individual responds to stress (entry gradient) (Kuhl, 1981, Kuhl, 2000, Baumann et al., 2007 and Koole, 2009). The goal of the present study is to investigate effects of oxytocin application on cortisol changes to a stressor as a function of efficient vs. inefficient ERA. We expect that low ERA individuals in the control (placebo) group show a stronger increase in cortisol than high ERA individuals in the control group. Moreover, we expect that low ERA individuals benefit from intranasal oxytocin application by showing a cortisol reaction that is less pronounced than the reaction from low ERA individuals treated with a placebo. Not least, finding a general increase of cortisol over the course of the stressor would speak to the effectiveness of the stressor.
نتیجه گیری انگلیسی
Results We found a main effect of measurement time, F(2.5, 79.4) = 9.4, p < .01, View the MathML sourceηp2 (partial eta square) = .23, where cortisol showed a typical increase in response to the stressor, peaking 20 min after stress onset, Mt1 (SD) = 5.7 (2.6), Mt2 = 5.4 (3.2), Mt3 = 7.6 (4.2), Mt4 = 5.9 (3.3), Mt5 = 4.7 (2.3). Moreover, the main effect of ERA was significant, F(1, 32) = 5.3, p < .05, View the MathML sourceηp2=.14. Specifically, collapsed across all other measurements high ERA individuals showed lower levels of cortisol than low ERA individuals, M = 5.1 (1.5) vs. M = 6.7 (2.8), respectively (not depicted). As expected, the three-way interaction was significant, F(2.5, 79.4) = 5.9, p < .05, View the MathML sourceηp2=.16, with the highest cortisol concentration 20 min after stress onset for low ERA individuals in the placebo group (cf. Fig. 1). All other main and interaction effects were non-significant. Mean salivary cortisol (±SEM) over the course of the psychosocial stress ... Figure 1. Mean salivary cortisol (±SEM) over the course of the psychosocial stress experiment (a modified version of the Trier Social Stress Test). Participants were randomly assigned to receive intranasal oxytocin (24 IU) or placebo and had either high or low ERA. OT was applied 45 min before stress-onset. The shaded area indicates the period of the 15 min public speaking task including preparation phase. The three-way interaction was significant at p < .01, indicating that individuals with low ERA benefit from oxytocin application. Additional post hoc comparisons revealed significant differences within placebo group between high and low ERA groups, 20 min, 45 min and 60 min after stress onset (p = .008, p = .008, and p = .02). There was also a significant difference within low ERA group between oxytocin and placebo groups 45 min after stress onset (p = .03). No differences were found between high and low ERA within oxytocin group. Figure options To examine the three-way interaction more precisely, we conducted post hoc tests based on the method of least significant differences. There were no significant differences between the groups 45 min before stress onset (within oxytocin: high vs. low ERA, p = .09; within placebo: high vs. low ERA, p = .21; within low ERA: oxytocin vs. placebo, p = .35; within high ERA: oxytocin vs. placebo, p = .052). Low ERA individuals of the placebo group showed significantly increased cortisol concentrations directly before stress onset, as well as 20 and 45 min after stressor onset as compared to baseline concentration (45 min before stress-onset), p < .05, p < .001, and p < .01, respectively. Further post hoc contrasts revealed significant differences between high and low ERA within the placebo group. Specifically, low ERA individuals showed higher cortisol levels than high ERA individuals 20 min after stress onset, p < .01, as well as 45 min, p < .01, and 60 min, p < .05. There were no significant differences in the oxytocin group, p > .86, p > .97, p > .39, respectively, suggesting that individuals with low ERA after oxytocin application have a dampened cortisol reaction similar to individuals with high ERA. Significant differences could be found within participants with low ERA between the oxytocin and placebo group at 45 min after stress onset, p < .05. Additionally, there was marginal difference between these two groups at 20 min, p < .08 after stress onset. There were no differences within individuals with high ERA, p > .40, p > .57, p > .96, respectively. The cortisol level of high ERA individuals in the OT group at 20 min after stress-onset did not significantly differ from baseline, p > .05.