Objective To study the effect of low frequency electrical stimulation on hormone levels in organs of Chinese tree shrews after death.Methods Giving Chinese tree shrews low frequency electrical stimulation.At 0 h, 3 h, 6 h, 12 h, 18 h, 24 h, 36 h and 72 h after death, the thyroid, liver, spleen were taken,and the levels of endothelin (ET), atrial natriuretic factor( ANF) , thromboxane ( TX) were determined by RIA method.At 0 h after death, midbrain ventral tegmental area ( VTA) of Chinese tree shrews was taken to detect the c-fos expression.Results After electrical stimula-tion, ET, ANF, TX levels in the cadaver organs and VTA c-fos expression of Chinese tree shrews were significantly in-creased than in the control group.The contents were decreasing with the time after death.Conclusions Low frequency e-lectrical stimulation can induce the synthesis and release of hormones in organs and c-fos expression in brain tissue of Chi-nese tree shrews.

Objective To study the effects of living environment conditions and animal-animal interaction on the blood hormone levels and psychological behavior in Chinese tree shrews .Methods Chinese tree shrews were raised in ca-ges of different space sizes or were administered reserpine for 15, 30, 60, 120, 180 days, respectively.Then the animals were anesthetized by ether inhalation , and blood samples were taken from the heart to detect the levels of blood testosterone (T), estradiol (E2), endothelin (ET), adrenaline (A) and noradrenaline (NA) by radioimmunoassay (RIA).Results 1.Chinese tree shrews were bred in large cage (D1group) or small cage (X1 group) for 15, 30, 60, 120, 180 days, re-spectively.Compared with the animals bred in the large cage (D1 group), the level of blood testosterone (T) was signifi-cantly reduced (P<0.01), and the levels of adrenaline , noradrenaline and endothelin were significantly increased in the small cage group (P<0.01 for all).2.The animals raised in small cages in close neighborhood with large cages for 15, 30, 60, 120, 180 days, respectively.The levels of testosterone, adrenaline and noradrenaline in the large cage group (X2 group) were significantly higher than those of the small cage group (X1 group) (P<0.01 for all).3.The adrenaline and noradrenaline levels were significantly lower in all the reserpine groups (P<0.01 for all).4.The animals bred in small cages (X1 group) and in small cages in close neighborhood with large cages showed sudden loss , reduced appetite, testicu-lar atrophy , penile prolapse and stress symptoms .The animals of the reserpine groups appeared gentle temperament , signif-icantly reduced activity and reduced appetite .However , after stopping the reserpine administration and feeding them in large cages , the animals gradually returned to normal behavior .Conclusion Both animals living environment conditions and animal-animal interaction may cause changes of blood hormone levels and psychological behavior in Chinese tree shrews.

Objective To study the effect of low frequency electrical stimulation on blood hormone levels in differ -ent animals.Methods At 12 h, 24 h and 36 h after low frequency electrical stimulation to Chinese tree shrews , Wistar rats, and BALB/c mice, respectively, the blood noradrenaline (NA) and endothelin (ET) levels were determined by ra-dioimmunoassay ( RIA) .Results The blood NA and ET levels of electrical stimulation group were significantly higher than that in the control group (P <0.01).At 24 h after reserpine treatment, the same electrical stimulation was given. The NA, ET levels were significantly decreased compared with that in the electrical stimulation group (P<0.05 to 0.01). Different animals responded to the same electric stimulus differently , following the order of Chinese tree shrews >Wistar rats >BALB/c mice.Conclusions Low frequency electrical stimulation can promote the release of noradrenaline and en -dothelin in Chinese tree shrews , Wistar rats and BALB/c mice.Reserpine can reduce the stress induced by low frequency electric stimulation to the body .

Objective To study the effect of maca extract on sport fatigue and its antioxidant effect.Methods 50 healthy male Wistar rats were randomly divided into control group (normal breeding,without swimming,equal amount of distilled water for gavage),simple swimming group (swimming,equal amount of distilled water for gavage),swimming and medicine group (divided into maca extract 4.0,8.0 and 16.0 g/(kg· bw) groups,respectively),10 rats in each group.All rats were freely swimming in the circulating water flow daily for 15 days.On the 16th day of experiment,liver tissue samples were collected.The liver lipid peroxide (LPO),superoxide dismutase (SOD),glutathione peroxidase (GSH-Px) and liver glycogen level were determined.Results When rats were administered with maca extract at the doses of 4.0,8.0,16.0 g/(kg· bw),respectively,the swimming time before sinking and the total swimming time were increased by 18.99%,64.46% and 90.69%,and 18.99%,56.23% and 94.72%,respectively,while the numbers of times of sinking were decreased by 27.44%,42.86%,64.11% (P<0.01),respectively,compared with the swimming rats without maca extract treatment.The LPO content in the liver of rats treated with maca extract 4.0,8.0,16.0 g/(kg· bw) were reduced by 31.31%,42.00% and 31.31%,respectively,while the levels of SOD,GSH-Px and liver glycogen were enhanced by 25.92%,31.82%,62.09%,12.33%,23.01%,46.36% and 17.83%,44.69%,62.99%,respectively,over those of rats without maca extract treatment.Conclusions Maca extract reduces the liver LPO level,increases liver glycogen level,improves the SOD and GSH-Px activity,therefore,plays a protective role in sport fatigue.

Objective To study the effect of noise pollution on serum hormone and heat shock protein-70(Hsp-70)levels in rats. Methods Forty male Wistar rats were randomly divided into control group(normal), experimental group(further divided into 35,65 and 85 dB three groups), each group 10 animals, stimulated for 30 min once a day, continually stimulated for consecutive 20 days. On the 21st day of experiment,the serum noradrenaline(NA),testosterone (T),dopamine(DA)and Hsp-70 levels were determined by enzyme-linked immunosorbent assay(ELISA). Results Compared with the control group, the body weight of experimental group(35, 65 and 85 dB groups)was reduced by 23.45%,30.13%, and 35.64%, respectively The serum T and DA levels were decreased by 9.12%, 20.06%, 37.99% and 15.49%, 8.31%, 24.88%, respectively; while the serum NA and Hsp-70 levels were increased by 35.08%, 171.52%,197.86%, and 39.34%, 195.09%, and 285.25%, respectively. All the result showed a significant difference(P<0.01). Conclusions Noise pollution can significantly affect the serum levels of hormone and heat shock protein-70 expression in rats.