The Effects Of Electrical Stimulation Of Nucleus Ambiguus On Thymosin,TGF-β,IL-2,IL-6 In Rat

Over the past 20 years, Advances in the field of neuroimmunology and more recently in psychoneuroimmunology have shown that the central nervous system (CNS) and the immune system are intimately linked and do not function as independent systems. The CNS can have widespread effects on the immune system following activation of the hypothalamic–pituitary–adrenal (HPA) axis and the sympathetic nervous system (SNS). Glucocorticoids released from the adrenal cortex have many important effects on metabolism but also have potent anti-inflammatory and immunosuppressive effects. Activation of SNS can occur during the classic fight-or-flight response and results in the release of catecholamines from the adrenal medulla and sympathetic nerve terminals. The effects of catecholamines are mediated through adrenoceptors and result in a wide range of physiological changes that best serve an animal in the face of imminent danger. However, lymphocytes and other cells of the immune system also express adrenoceptors and may, therefore, be influenced by circulating catecholamines. The presence of such a close association between sympathetic nerve fibers and cells of the immune system could provide a direct mechanism enabling the CNS to regulate specific aspects of the immune response. Thus, it appears that the CNS can communicate with the immune system in a general sense via endocrine outflow from the CNS, adrenocorticotropine (ACTH), glucocorticoids to the periphery, but also more directly by means of sympathetic innervation of both primary and secondary lymphoid organs. The immune system, in turn, may communicate with CNS through immune products, primarily cytokines leading to the direct CNS activation or to release of CNS-derived cytokines. In addition, immunocytes synthetize and secrete hormones, neurotransmitters and neuropeptides, similar to those released from the CNS, which react with common immune and central nervous systems receptors.Some investigators have taken a neuroanatomic approach to evaluate the role of the CNS in modulation of immune reactivity. Support for a concept of neural–immune interactions was found in reports which indicated that damage to the CNS by electrolytic lesions especially in the hypothalamus and limbic system induce a variety of immune alterations. Studies utilizing CNS lesions or stimulation suggest that specific regions of the brain may modulate immune activity.nucleus ambiguus(Amb),belonging to nucleus nervi vagi ,is special nervus visceralis nucleus. The Amb lies oblongata ventrolateral formatio reticularis and involves a variety of neurons,such as adrenergic neuron, cholinergic neuron, peptidergic neuron.up to now,the Amb,probably owing to its trational focus in controlled respiration, digest and cardiovascular activity,is less well studied in immunoregulation. In the present experiment we investigated whether acute electric stimulation of Amb in anesthetized rat will influence Con A-induced splenic lymphocyte proliferations,IL-2,IL-6,as well as mRNA of TGF-βand thymosin in thymus.We found that the Con A-induced splenic lymphocyte proliferation and the secretions of IL-2 and IL-6 were both significantly enhanced on hours 0.5, 1 and 2 following the effective electric stimulation of Amb in comparison with those of matching control rats sham-stimulated,and subsequently they begined decreasing .but the mRNA of TGF-βand thymosin in thymus were both considerablely decreased on hours 0.5, 1 and 2 following the effective electric stimulation of Amb in comparison with those of matching control rats sham-stimulated,and resumed common level after 3h. The cause that the increasement of splenic lymphocyte activity and the decreasement of thymus cell activity is possibly that acute electric stimulation of Amb induced both activation of neuroendocrine system and the sympathetic nervous system(SNS).moreover,in the acute experiment, creatural physical condition and age can significantly affluence the experimental result;sometime the rusult was possibly opposite.Our experiment hints that the Amb play a important role in Neuroen- docrine-immune interactions,and we presume that the Amb can transfer the regulating signals from the CNS to the immune system.