Liuwei Dihuang decoction（LW），a classical traditional Chinese medicinal prescription with the effect of “nourishing Kidney-Yin”，consists of six herbs including Rehmannia glutinosa (Shudi),Cornus officinalis(Shauzhuyu)，Dioscorea opposita(Shanyao)，Alisma orientale(Zexie)，Porie cocos（Fuling）and Paeonia suffruticosa（Mudanpi）．It has long been used clinically in the treatments of many kinds of diseases with the sign of “Kidney-Yin deficiency”，such as cancer，diabetes，autoimmue diseases，menopausal syndrome in traditional Chinese medical treatments．The effectiveness of it has been well documented during the long-term clinical practices．In our study，the effects and the possible active mechanisms of LW on learning and memory ，neuroendocrine and immune functions were studies from the angle of neuroendocrine immunomodulation（NIM）network ．In chemical fractionation and purification of the immunoactive fractions or components contained in LW，the method of a close collaboration between pharmacological and chemical studies was employed．The chemical fractionation was begun from the decoction and guided by pharmacological activity evaluation．The results showed that oral administration of LW significantly improved learning and memory abilities in several kinds of model animals such as senescence accelerated mice (SAM)，chronic hanging stress-loaded mice and corticosterone-treated mice and the mechanism studies suggested that the effects were achieved through several ways．LW significantly decreased the plasma level of corticosterone in SAM-prone/8 (SAMP8) ，a substrain of SAM．SAMP8 showed a marked elevation of plasma level of corticosterone with advancing age in comparison with SAMR1 ，a substrain of senescence resistant of SAM．LW also significantly improved the secretion of testosterone by primary cultured testis cells from SAMP8．The immunopharmacological studies showed that oral administration of LW not only improved the immune functions in several immunodeficient model animals such as cyclophospharmide-treated mice and SAMP8，but also modulated or corrected the imbalance of immune functions manifested in autoimmune model animals includig adjuvant arthritis rats and campylobacter jejuni primed mice．Under the guidance of activity evaluation，several immunoactive fractions and pure compounds were obtained from the decoction．The effects of some fractions and compounds were studied and the results showed that they possessed potential immunopharmacological effects．The preliminary study suggested that LW possessed wide pharmacological effects and the basic effect of LW，we postulate，is modulation the balance of NIM network disturbed in many pathological conditions．It is also suggested that our method employed in the study of LW is an effective and practicable way in modern studies of tradltional Chinese medicinal prescriptions．
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