Repeated stressful experiences affect limbic dopamine release during and following stress

Institute of Medical Pharmacology, University La Sapienza, Rome, Italy.
Brain Research (Impact Factor: 2.84). 05/1992; 577(2):194-9. DOI: 10.1016/0006-8993(92)90274-D
Source: PubMed

ABSTRACT The effects of repeated restraint stress exposures (daily 60 min, for 6 days) on extracellular dopamine in the nucleus accumbens, during and after the stress experience, have been investigated in rats by in vivo microdialysis. On the first day, restraint increased dopamine release during the first 40 min followed by a return to basal levels (50-60 min later). As soon as restraint ceased and the rats were set free, there was another increase in dopamine release lasting 40 min. On the second and third day, restraint produced only a slight increase in dopamine release, while no significant changes were evident from the fourth to the sixth day. By contrast, from the second to the sixth day the increase in dopamine release observed once rats were freed, was unchanged in comparison to the first day. The present results show that the activation of the mesolimbic dopaminergic system induced by aversive stimuli adapts to repeated experiences differently from that produced by pleasurable events, suggesting that aversive and rewarding experiences involve different neural systems.

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Available from: Stefano Puglisi-Allegra, Aug 05, 2015
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    • "Both leptin and insulin have been suggested to exert a regulatory function in the meso-limbic reward system, and especially insulin increased expression of dopamine transporters in the ventral tegmental area [62] [63]. As described above, the meso-limbic reward system is highly implicated in the psycho-emotional disorders in relation with the stress axis function [22] [23] [24] [25] [26] [27]. Thus, a tentative modulation , if any, in the meso-limbic reward system by increased leptin and/or insulin with increased fat depot is suggested to play a role in the mood elevation by palatable food access. "
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    ABSTRACT: This study examined the effects of highly palatable food during adolescence on the psycho-emotional and neural disturbances caused by early life stress experience in female rats. Female Sprague-Dawley pups were separated from dam for 3 h daily during the first two weeks of birth (MS) or left undisturbed (NH). Half of MS females received free access to chocolate cookies in addition to ad libitum chow from postnatal day 28. Pups were subjected to the behavioral tests during young adulthood. The plasma corticosterone response to acute stress, ΔFosB and brain-derived neurotrophic factor (BDNF) levels in the brain regions were analyzed. Total caloric intake and body weight gain during the whole experimental period did not differ among the experimental groups. Cookie access during adolescence and youth improved anxiety-/depression-like behaviors by MS experience. ΔFosB expression was decreased, but BDNF was increased in the nucleus accumbens of MS females, and ΔFosB expression was normalized and BDNF was further increased following cookie access. Corticosterone response to acute stress was blunted by MS experience and cookie access did not improve it. Results suggest that cookie access during adolescence improves the psycho-emotional disturbances of MS females, and ΔFosB and/or BDNF expression in the nucleus accumbens may play a role in its underlying neural mechanisms.
    International journal of biological sciences 09/2015; 11(10):1150-9. DOI:10.7150/ijbs.12044 · 4.51 Impact Factor
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    • "It has been reported that reduced dopaminergic function within the NAc may cause depression-like behaviors in rodents [44], and the striatal dopaminergic activity was suggested to be associated with the severity of anhedonia in depressed patients [45]. The NAc is activated in response to behavioral stress paradigm [46,47], suggesting its implication in the stress-responsive HPA axis regulation. Rats that experienced our MS protocol showed not only HPA axis dysfunction but also reduced dopaminergic activity in the NAc [48]. "
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    ABSTRACT: Background This study was conducted to examine the effects of ad libitum consumption of highly palatable food (HPF) during adolescence on the adverse behavioral outcome of neonatal maternal separation. Methods Male Sprague-Dawley pups were separated from dam for 3 hours daily during the first 2 weeks of birth (maternal separation, MS) or left undisturbed (nonhandled, NH). Half of MS pups received free access to chocolate cookies in addition to ad libitum chow from postnatal day 28 (MS+HPF). Pups were subjected to behavioral tests during young adulthood. The plasma corticosterone response to stress challenge was analyzed by radioimmunoassay. Results Daily caloric intake and body weight gain did not differ among the experimental groups. Ambulatory activities were decreased defecation activity and rostral grooming were increased in MS controls (fed with chow only) compared with NH rats. MS controls spent less time in open arms, and more time in closed arms during the elevated plus maze test, than NH rats. Immobility duration during the forced swim test was increased in MS controls compared with NH rats. Cookie access normalized the behavioral scores of ambulatory and defecation activities and grooming, but not the scores during the elevated plus maze and swim tests in MS rats. Stress-induced corticosterone increase was blunted in MS rats fed with chow only, and cookie access normalized it. Conclusion Prolonged access to HPF during adolescence and youth partly improves anxiety-related, but not depressive, symptoms in rats that experienced neonatal maternal separation, possibly in relation with improved function of the hypothalamic-pituitary-adrenal (HPA) axis.
    06/2014; 29(2):169-78. DOI:10.3803/EnM.2014.29.2.169
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    • "However, vehicle-injected D3KO mice failed to show such an increased in FST as compared to WT controls [36], suggesting an increased resistance to injection-induced stress before. In rodent models, immobilization stress is known to be a severe stressor which can activate the HPA axis, accelerate dopamine synthesis in mesolimbic dopamine neurons and enhance dopamine release in limbic brain regions [37] [38] [39] [40]. Recent work has shown that dopamine, acting through both D1 and D2 receptors , exert stimulatory effect on the activation of the HPA axis in response to immobilization stress [41]. "
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    ABSTRACT: A central problem in understanding the dopamine system in anxiety and depression is to specify functions of different members of the dopamine receptor family. Recent studies have reported that the dopamine D2/D3 receptor agonist pramipexole exerts an antidepressant-like effect in the chronic mild stress model and in the behavioral despair model, suggesting dopamine D3 receptor may be an important target for antidepressant actions. The aim of the present study was to examine the role of dopamine D3 receptor on the anxiety-like and depression-like behaviors induced by immobilization stress. We subjected D3 receptor knockout (D3KO) mice to a series of behavioral paradigms after acute (1hour) or chronic (1hour a day for at lest 14 days) immobilization stress. The results showed that immobilization stress significantly altered the anxiety-like behaviors (open field test and elevated plus maze) and depression-like behaviors (tail suspension test) in both D3KO mice and their wild-type littermates. Moreover, further analysis of the data indicated that the D3KO mice, but not their littermates, failed to show a change in immobility time in the tail suspension test after the acute and chronic stress as compared to intact controls, suggesting an increased resistance to the immobilization stress given before behavioral tests. Although our study did not suggest a significant role of D3 receptor in regulating basal anxiety-like and depression-like behaviors, it demonstrated the mice lacking D3 receptor might be more resistant to stressful procedure than their WT littermates.
    Behavioural brain research 01/2013; 243(1). DOI:10.1016/j.bbr.2013.01.019 · 3.03 Impact Factor
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