Neuro-endocrine systems

Neuro-endocrine systems associated with stress... 

Two major neuro-endocrine systems have been associated with stress. The first one is associated with acute stressful states such as fear, anger and excitement (Amkraut and Solomon 1975) and is called the sympathetic-adrenal-medullary system (SAM). SAM activation has been associated with action proneness and raised effort and it has also been described as the fight or flight system . It is activated when the organism is challenged in its control of the environment, and is accompanied by the release of catecholamines (epinephrine and norepinephrine) into the bloodstream. Catecholamine output is increased in response to a challenge to perform well (Frankenhaeuser et al. 1980 Lundberg and Frankenhaeuser 1980). 

The second neuro-endocrine system is the hypothalamic-pituitary-adrenal-cortical (HPAC) system (Asterita 1985 Cannon 1932 Cannon and de la Paz 1911 Frankenhaeuser 1983 Henry and Stephens 1977 Levine and... 

The biochemical basis for many of the psychotropic and neurological effects of manganese intoxication are increasingly well-documented in terms of altered neuro-transmitters, receptors, and enzyme activities [530], Alessio et al. [531] have documented the interference of Mn(II) with the neuro-endocrinal system. Research by Bonilla and Prasad [532] and Eriksson et al. [533] indicate changes in levels of biogenic amines in discrete... 

Modulation of neuro-endocrine system activities, hypothalamic adrenal-gonadal system... 

Among vertebrate species, the neuro-endocrine-immime system is responsible for many complex, inter-related physiological processes including neuronal, homeostatic, reproductive and immune functions. There are four main types of hormone polypeptides, eicosanoids, steroids and thyroid hormones. Reflecting the inter-dependency of the neiiro-endocrine and immune systems, hormones, neuropeptides and other neiirotransmitters are known to be produced by some immune cells and play a role in the regulation of the immune system, while endocrine and nervous tissues express receptors for many substances produced by the immune system. The major focus of interest in endocrine disruption has... 

Hydroxy tryptamine, or serotonin, is a neurotransmitter in the central nervous system (CNS). The nerve-cell bodies of the major serotoninergic neurones are in the midline raphe nuclei of the rostral pons, and ascending fibers innervate the basal ganglia, hypothalamus, thalamus, hippocampus, limbic forebrain, and areas of the cerebral cortex. The serotoninergic system plays an important role in the control of mood and behavior, motor activity, hunger, thermoregulation, sleep, certain hallucinatory states, and some neuro-endocrine mechanisms. 

Little is known about the molecular mechanisms and complexity converting psychosocial stress into cellular dysfunction in the brain, endocrine, and immune systems. How ordinary and sustained maladapted psychosocial stressors, chronic stress, and an unhealthy lifestyle activate and exert an influence on the biochemistry of the neuro-endocrine-immune axes with implications for future health or disease, is an upcoming innovative research field due to the new and emerging fields of proteomics, metabonomics, and biochip technologies. 

This is another evidence to conclude that delayed consequences are in direct relation to the damages inflicted on the central nervous system subcortical structures. No doubt, a definite limit of affection of subcortical structures exists, beyond which the course of intoxication will be confused. Under limit of affection one should understand not so much the intensity, but the time period during which the poisonous substances were applied intra-venal application, as compared to prolonged, for example skin resorption, has decreased effect in the formation of delayed neuro-endocrine toxicity. 

Rindi G, Kloppel G, Alhman H, et al. TNM staging of foregut (neuro)endocrine tumors a consensus proposal including a grading system. Virchows Arch. 2006 449 395-401. 

In vitro exposure is most straightforward for direct immunotoxicants. However, materials that require biotransformation would require special culture systems (e.g., culture in the presence of S9). Furthermore, an additional limitation of in vitro methods would be the physicochemical characteristics of the test material, which may interfere with the in vitro system. Such characteristics may include the need for serum, effects of vehicle on cells (such as DMSO), and chemical binding to cells. In vitro systems do not take into account the interactions of the different components and it is difficult to reproduce in vitro the integrity of the immune system. Finally, in vitro systems do not account for potential neuro-immuno-endocrine interactions. 

Clearly an important part of understanding stress-related disorders is to better define the chemistry of psycho-neuro-immuno-endocrine response patterns over time, from the healthy and time-limited to unhealthy and sustained individual. There is growing evidence that a physiological communication exists between the brain and the immune system. Several studies have shown that the white blood cells of the immune... 

In vitro systems do not account for potential neuro-immuno-endocrine interactions. There is no anticipated resolution for this deficiency at present. 

Our metabolism consists of a huge number of biochemical processes which are generally in a state of dynamic equilibrium called homeostasis. Whenever stressors in the form of extrinsic or intrinsic forces are applied, the state of homeostasis is challenged, and the stress system in our body is activated. Normal stress is essential for maintenance of mental and physical health. The hypothalamic-pituitary-adrenal (HPA) axis is the main constituent of the stress system because it serves as a key junction for neuro, immuno and endocrine (hormonal) systems [7]. Acute or chronic stress causes dysregulation of the stress system. This situation leads to various pathophysiologic states that include psychiatric, endocrine/metabolic, and immunologic disorders. 

In fact, ACTH secretion is regulated by a neuro-hormonal mechanism and a humoral feedback mechanism. The neurohormonal control of ACTH secretion involves what has been referred to as a third-order neuroendocrine mechanism. Three steps are involved in this control. A stimulus (stress, for example) brings the central nervous system to secrete a hormone (CRF), which acts on another endocrine structure in the anterior lobe of the hypophysis where it induces the secretion of second hormone (ACTH), which ultimately acts on the target endocrine gland—the adrenal cortex [40, 56-60]. 

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