Effects of Mulberry Extract on Regulation of Sex Hormone and Hypothalamic Neurotransmitter in Naturally Aged Female Rats

[Objective] This study aimed to investigate the effects of different mulberry extracts on sex hormone and hypothalamic neurotransmitter in naturally aged female rats and reveal the mechanism and material basis of anti-aging effect of mulberry. [ Method] Fourteen-month-old SD female rats were selected and ran- domly divided into model group, positive control group, high-dose and low-dose water extract groups, high-dose and low-dose 50% ethanol extract groups, and high-dose and low-dose 95% ethanol extract groups; four-month-old SD female rats were used as blank control group. After eight weeks of drug administration, the levels of 17β-estradiol （E2 ）, follicle- stimulating hormone （FSH） and luteinizing hormone （LH） in serum and beta-endorphin （β-EP） in hypothalamus were de- termined by radioimmunoassay; the levels of norepinephrine （ NE）, dopamine （ DA）, 5-hydroxy tryptamine （5-HT） and 5-HIAA in hypothalamus were determined by fluorescence spectrometry. [ Result] Water extract of mulberry can increase the level of E2 and reduce levels of FSH and LH in serum, and increase the level of fl-EP and reduce levels of DA, 5-HT and 5-HIAA in hypothalamus of naturally aged female rats. Water extract of mulberry exhibited higher effects than 50% eth- anol extract and 95% ethanol extract. [ Conclusion] Mulberry could significantly improve the function of hypothalamic peptide neurotransmitter in naturally aged rats, correct disorders of hypothalamic monoamine neurotransmitter, and treat perimenopausal syndrome by regulating reproductive endocrine function, which might be related with its water-soluble components and require further investigation and development.

Conceptual models of forest dynamics in environmental education and management:keep it as simple as possible,but no simpler

Background：Conceptual models of forest dynamics are powerful cognitive tools,which are indispensable for communicating ecological ideas and knowledge,and in developing strategic approaches and setting targets for forest conservation,restoration and sustainable management.Forest development through time is conventionally described as a directional,or ＂linear＂,and predictable sequence of stages from ＂bare ground＂ to old forest representing the ＂climax-state＂.However,this simple view is incompatible with the current knowledge and understanding of intrinsic variability of forest dynamics.Hypothesis：Overly simple conceptual models of forest dynamics easily become transformed into biased mental models of how forests naturally develop and what kind of structures they display.To be able to communicate the essential features and diversity of forest dynamics,comprehensive conceptual models are needed.For this end,Kuuluvainen（2009） suggested a relatively simple conceptual model of forest dynamics,which separates three major modes of forest dynamics,and incorporates state changes and transitions between the forest dynamics modes depending on changes in disturbance regime.Conclusions：Conceptual models of forest dynamics should be comprehensive enough to incorporate both longterm directional change and short-term cyclic forest dynamics,as well as transitions from one dynamics mode to another depending on changes in the driving disturbance regime type.Models that capture such essential features of forest dynamics are indispensable for educational purposes,in setting reference conditions and in developing methods in forest conservation,restoration and ecosystem management.