Chronic stress induced changes in LH secretion: The contribution of anorexia associated to stress

The Research Domain Criteria (RDoC) initiative provides a strategy for classifying psychopathology based on behavioral dimensions and neurobiological measures. Neurodevelopment is an orthogonal dimension in the current RDoC framework; however, it has not yet been fully incorporated into the RDoC approach. A combination of both a neurodevelopmental and RDoC approach offers a multidimensional perspective for understanding the emergence of psychopathology during development. Environmental influence (e.g., stress) has a profound impact on the risk for development of psychiatric illnesses. It has been shown that chronic stress interacts with the developing brain, producing significant changes in neural circuits that eventually increase the susceptibility for development of psychiatric disorders. This review highlights effects of chronic stress on the adolescent brain, as adolescence is a period characterized by a combination of significant brain alterations, high levels of stress, and emergence of psychopathology. The literature synthesized in this review suggests that chronic stress-induced changes in neurobiology and behavioral constructs underlie the shared vulnerability across a number of disorders in adolescence. The review particularly focuses on depression and substance use disorders; however, a similar argument can also be made for other psychopathologies, including anxiety disorders. The summarized findings underscore the need for a framework to integrate neurobiological findings from disparate psychiatric disorders and to target transdiagnostic mechanisms across disorders.

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Photoperiodic modulation of the dopaminergic control of pulsatile LH secretion in sheep

Journal of Endocrinology ◽

10.1677/joe.0.1430025 ◽

1994 ◽

Vol 143 (1) ◽

pp. 25-32 ◽

Cited By ~ 27

Author(s):

D J Tortonese ◽

G A Lincoln

Keyword(s):

Dopaminergic System ◽

Pulse Frequency ◽

Inhibitory System ◽

Pulsatile Gnrh ◽

Photoperiodic Regulation ◽

Series Of Experiments ◽

Induced Changes ◽

Lh Secretion ◽

Short Days ◽

Sustained Increase

Abstract This study was conducted to investigate whether the photoperiodic regulation of the seasonal changes in pulsatile LH secretion in the ram involves changes in the activity of inhibitory hypothalamic dopaminergic (DA) pathways. To test this hypothesis, a series of experiments was carried out in Soay rams in which the effects of a DA-D2 receptor antagonist (sulpiride) or a DA-D2 receptor agonist (bromocriptine) on the pulsatile secretion of LH were determined under both long and short days. In each experiment blood samples were collected every 10 min for 8 h starting at the time of vehicle, sulpiride or bromocriptine injections to assess concentrations of LH. Sulpiride (0·59 mg/kg, s.c.) administered to rams under long days induced an immediate and sustained increase in the secretion of LH that lasted for approximately 4 h (P<0·05; ANOVA); this LH response reflected both a rise in mean concentrations (0·247 ± 0·03 vs.0·452 ± 0·1 μg/1) and an increase in the frequency of LH pulses (0·5±0·5 vs. 2·33±0·42 pulses/8 h; P<0·01). In contrast, under short days sulpiride had no effect. Bromocriptine (0·06 mg/kg, s.c.) administered to rams under long days, when LH concentrations were low, was without effect, but when given to rams under short days significantly (P<0·05) suppressed mean LH concentrations (0·627 ±0·08 vs. 0·320 ± 0·02 μg/l) and LH pulse frequency (4·86 ±0·46 vs. 2·43 ±0·37 pulses/8 h). In an additional experiment, pimozide (total dose: 0·16 mg/kg, i.m.), a DA antagonist less specific for DA-D2 receptors than sulpiride, was ineffective in modifying LH secretion in sexually inactive rams exposed to long days. These results are consistent with the hypothesis that an inhibitory dopaminergic system is involved in the regulation of pulsatile LH secretion in the ram. The induced changes in LH pulse frequency under long days (increased by sulpiride) and under short days (decreased by bromocriptine) indicate that, under both photoperiods, DA acts within the hypothalamus, via a specific DA-D2 receptor, to influence pulsatile GnRH secretion. A photoperiodic-induced activation of this inhibitory system may therefore represent the mechanism whereby long days suppress LH secretion and lead to the sexually inactive state characteristic of the non-breeding season. Journal of Endocrinology (1994) 143, 25–32

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Vitamin D Regulatory Effect on Restraint Stress-Induced Changes on Serum Corticosterone and Hippocampus BDNF Levels in Male Rats

Middle East Journal of Rehabilitation and Health ◽

10.5812/mejrh.115164 ◽

2021 ◽

Vol In Press (In Press) ◽

Author(s):

Katayoun Sedaghat ◽

Sara Choobdar ◽

Ahmad Reza Bandegi ◽

Zahra Ghods

Keyword(s):

Vitamin D ◽

Chronic Stress ◽

Restraint Stress ◽

Male Rats ◽

Negative Effects ◽

Bdnf Level ◽

Serum Corticosterone ◽

Protein Levels ◽

Induced Changes ◽

The Impact

Background: Chronic stress exerts negative effects on cognitive functions through inducing changes in the hippocampus. Brain-derived neurotrophic factor (BDNF) is an essential factor in cognitive activities, which is considerably reduced under chronic stress. 1,25(OH)2 vitamin D plays neuroprotective roles partially by regulating the expression of various neurotrophic factors. Objectives: Since few studies have studied the impact of vitamin D on BDNF level, we conducted this brief experiment to understand the role of vitamin D in maintaining hippocampal BDNF protein levels by using restraint as a model of chronic stress in rats. Methods: Rats underwent restraint stress 3 h/day for 28 days, during which they received vitamin D (5, 10 μg/kg) or its vehicle (IP, twice weekly). After the stress period, serum corticosterone (CORT) and hippocampus BDNF protein levels were measured. Results: Restraint stress increased serum CORT (P < 0.001) and reduced BDNF protein levels (P < 0.001) as compared to the non-stress group. Vitamin D markedly maintained BDNF level close to normal (P < 0.001), but did not change CORT level significantly. Conclusions: This study demonstrated that 3h/day of chronic restraint stress for 28 days boosted serum CORT and declined hippocampal BDNF levels, similar to stronger restraint stress models. Vitamin D maintained BDNF level close to normal in the hippocampus, but it did not affect CORT level significantly.

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