Forty rots were randomized into 2 groups and naloxone or saline were injected to therats after they were inflicted with hemorrhagic shock at sea level and at a simulated altitude of4000m respectively to observe the ef...Forty rots were randomized into 2 groups and naloxone or saline were injected to therats after they were inflicted with hemorrhagic shock at sea level and at a simulated altitude of4000m respectively to observe the effects of naloxone on left ventricular systolic pressure(LVSP),left ventricular diastolic pressure(LVDP),the maximal changing rate of LVSP(dp/dt max),heartrate(HR),and survival time of the animals.Plasma β-endorphin(β-EP)was determined beforeand after hemorrhage to observe the relationship between β-EP and hemorrhagic shock.It wasfound that the circulatory parameters of hemorrhagic shock changed more markedly at high alti-tude than at sea level,naloxone could restore these parameters and prolong the survival time inboth the animals of the sea level and high altitude groups,and plasma β-EP level was elevatedafter hemorrhage especially in those animals at high altitude.These findings indicate:(1)Hemorrhagic shock at high altitude is usually accompanied with severe clinical manifestations,rapid progression,and high mortality.(2)β-EP seems to participate in the pathologicalmanifestafions of hemorrhagic shock at high altitude,and its depressive action on myocardialcontraction may be one of the factors inducing hemorrhagic shock.(3)Naloxone possesses defi-nite property to comet hemorrhagic shock at high altitude.展开更多
We observed for the first time the differences of immunoreactive β-endorphin(IR -β- EP) content in plasma, pituitary and hypothalamus of rats under various conditionsusing radioimmunoassay (RIA) and the effects of n...We observed for the first time the differences of immunoreactive β-endorphin(IR -β- EP) content in plasma, pituitary and hypothalamus of rats under various conditionsusing radioimmunoassay (RIA) and the effects of naloxone and β - endorphin (β- EP) antiserumon initial time of convulsions (ITC), severity of convulsions(SOC) and mortality on surface(MOS) of rats to hyperbaric oxygen(HBO). The results suggest thatβ- EP may partici-pate in the course of oxygen - induced convulsions and be one of endogenous convulsion - causingagents.展开更多
To observe plasm a β-endorphin (β-EP) and gonadotrophin releasing horm one (GnRH), hum an chorionic gonadotrophin (hCG), progesterone (P4) levelsin w om en w ith early threatened abortion and w ith a history of re...To observe plasm a β-endorphin (β-EP) and gonadotrophin releasing horm one (GnRH), hum an chorionic gonadotrophin (hCG), progesterone (P4) levelsin w om en w ith early threatened abortion and w ith a history of recurrent spontaneous abortions (RSA). Tw enty patientsw ith threatened abortion at7～8 w eeksof gestation w ere re- cruited, allof them had a history of 3 or m ore recurrentunexplained abortions. They w ere treated w ith psychologicalconsultation accompanied by traditionalChinese herbs. Blood samples w ere taken to m easure β-EP, GnRH, hCG and P4 levels by radioim - m unoassay (RIA). The treatm ents w ere continued till10～12 w eeks, blood w astaken during this period to compare changes in these peptides / horm ones. Tw enty norm al pregnantw om en at7～8 and 10～12 w eeksand 20 patientsw ith incompleteabortion at 10～12 w eeksw ererecruited for comparativestudies. Results: (1) In norm alpregnant w om en, plasm a β-EP, GnRH, hCGand P4 levelsat10～12 w eeksw ere significantly higher than thatat7～8 w eeks (P< 0.01). (2) In patients w ith threatened abortion and a history of RSA, plasm a β-EP levels at7～8 w eeks w ere significantly higher than those of norm al pregnantw om en (P< 0.01); on the contrary, plasm a GnRH, hCGand P4 levelsin these patientsw ere significantly low er than thosein norm alcases (P< 0.01). After treatm ent, 16 of the 20 patients succeeded in m aintaining their pregnancies, the levels of the four plasm a contents at10～12 w eeks w ere sim ilar to thosein norm alpregnantw om en (P> 0.05). (3) Plasm a β-EPlevelsin patientsw ith incomplete abortionsat10～12 w eeksw ere dram atically higher and GnRH, hCGand P4 levelsw ere low er than in norm alpregnantw om en (P< 0.01). β-EP m ightplay a role in the pathophysiology of spontaneousabortion.展开更多
The effects of opioid peptides on iminune responses were investigated. It was found that β-endorphin (β-END) can depress proliferative responses to PHA in rat splenocytes but enhance those in mice, and it could also...The effects of opioid peptides on iminune responses were investigated. It was found that β-endorphin (β-END) can depress proliferative responses to PHA in rat splenocytes but enhance those in mice, and it could also inhibit the plaque-forming cell (PFC) response to sheep red blood cells when mouse splenocytes immunized in vivo were cultured in vitro with the peptide. The peptide antagonist naloxone was able to reverse β-END suppression of the PFC response. The data indicate that β-END suppresses antibody production or secretion via a specific opioidreceptor-mediated mechanism.展开更多
The effect of electromagnetic field on plasma β endorphin in 30 patients with migraine were studied in the experiment. All subjects received a 20 minute repetitive transcranial magnetic stimulation (Frequency 10Hz, A...The effect of electromagnetic field on plasma β endorphin in 30 patients with migraine were studied in the experiment. All subjects received a 20 minute repetitive transcranial magnetic stimulation (Frequency 10Hz, Average intensity 8mT) per time, and the total experiment lasted 20 times. Before and after the experiment, the EEG and plasma β endorphin were tested. The results show that the level of plasma β endorphin in patients blood increased significantly from (73.486±26.002)mg/ml to (116.934±67.592)mg/ml (p<0.01), and the EEG average magnitude of the migraine patients were improved obviously from 41.77μV to 47.42μV.展开更多
AIM To study the role of cholecystokinin- octapeptide (CCK-8). β-endorphin (β-EP). and gastrin in an anorexic infantile rat model and no subsequent regulation of nose peptides by the Yunpi complex prescription Er...AIM To study the role of cholecystokinin- octapeptide (CCK-8). β-endorphin (β-EP). and gastrin in an anorexic infantile rat model and no subsequent regulation of nose peptides by the Yunpi complex prescription ErBao Granule. METHODS We fed infantile rats with special prepared forage. A liquid extract of ErBao Granule was administered to the rats daily for 3 weeks, CCK-8, β-EP, and gastrin concentrations in hypothalamus, gastric antrum, and plasma of the rats were measured by radioimmunoassay, and were compared with controls. RESULTS Treatment of rats with ErBao Granule inhibited CCK-8 secretion and increased β-EP and gastrin secretion. CCK-8 concentration in hypothalamus and plasma of model control group increased significantly and correlated negatively with food intake of models, respectively. β-EP concentration in gastric antrum and plasma of model control group decreased significantly and showed a positive correlation with food intake of models, respectively. Hypothalamus concentration of β -EP was similar in models and controls. Gastrin concentration in gastric antrum of models was lower than in the blank control group, and correlated positively to food intake of models. Finally, CCK-8 concentrations in plasma of rats showed a positive correlation with plasma β-EP (r=-0.68, P<0.05). CONCLUSION The increased plasma and hypothalamus concentration of CCK-8, decreased gastric antrum and plasma level of β -EP, and decreased gastric antrum concentration of gastric are associated significantly with the anorexia of infantile anorexic rat models produced by special forage. ErBao Granule can reverse these changes, which may be the major mechanisms of ErBao Granule simulating feeding.展开更多
Objective:To evaluate the effectiveness and safety of electroacupuncture in conjunction with additional medications in providing analgesia and stabilizing hemodynamic parameters during total thyroidectomy.Methods:This...Objective:To evaluate the effectiveness and safety of electroacupuncture in conjunction with additional medications in providing analgesia and stabilizing hemodynamic parameters during total thyroidectomy.Methods:This randomized controlled trial included 100 patients who underwent a total thyroidectomy between October 2022 and October 2023 at the Vietnam National Hospital of Acupuncture.The patients were randomized into two groups.The electroacupuncture analgesia(EA)group received EA stimulation at five acupuncture points:Hegu(LI 4),Neiguan(PC 6),Shuitu(ST 10),Quepen(ST 12),and Yifeng(SJ 17),while the control group received a bilateral superficial cervical plexus block.Primary outcomes included the level of analgesia and perioperative vital signs in both groups.Additionally,pain thresholds and serum b-endorphin levels were measured before and after electroacupuncture in the EA group.Results:Complete analgesia(Level A)was attained in 86%and 76%of the patients in the EA and control groups,respectively,with no significant difference between the two groups(P=1.00).In the EA group,the mean pain threshold after receiving EA doubled(648.7(77.4)g/s vs.305.3(45.3)g/s,P<.001),and the mean serum b-endorphin level increased by approximately 13.5 pg/mL(P<.001).All patients remained hemodynamically stable throughout the surgery.Conclusion:EA,in conjunction with additional medications that stimulate five acupuncture points,LI 4,PC 6,ST 10,ST 12,and SJ 17,was well tolerated and effectively maintained a suitable level of analgesia and hemodynamic stability during total thyroidectomy.展开更多
目的:探讨小鼠疼痛模型的昼夜节律和注射用蜂毒(Bee venom for injection,BVI)镇痛作用的昼夜差异及其相关机制。方法:采用热板法、辐射热甩尾法建立小鼠疼痛模型,在6个授时(Zeitgeber time,ZT)时间点(ZT2、ZT6、ZT10、ZT14、ZT18、ZT22...目的:探讨小鼠疼痛模型的昼夜节律和注射用蜂毒(Bee venom for injection,BVI)镇痛作用的昼夜差异及其相关机制。方法:采用热板法、辐射热甩尾法建立小鼠疼痛模型,在6个授时(Zeitgeber time,ZT)时间点(ZT2、ZT6、ZT10、ZT14、ZT18、ZT22)测量痛阈并分析其昼夜节律。将合格昆明小鼠随机分为注射用蜂毒大剂量(Bee venom for injection-High dose,BVI-H)、注射用蜂毒中剂量(Bee venom for injection-Medium dose,BVI-M)、注射用蜂毒低剂量(Bee venom for injection-low dose,BVI-L)、吗啡(Morphine,MOR)和模型(Model,MOD)组;每组再根据小鼠痛阈的昼夜节律分为两个亚组,分别在痛阈的峰值和谷值2个时间点给药。观察各组对热板法、辐射热甩尾法和扭体法疼痛模型小鼠行为学影响的动态变化;ELISA法检测血清P物质(Substances P,SP)、β-内啡肽(Beta-endorphin,β-EP)和IL-1β(interleukin-1β,IL-1β)水平。结果:小鼠疼痛模型的痛阈显示出峰值在明中期(ZT6)、谷值在暗后期(ZT22)的昼夜节律。BVI三个剂量组和MOR组均显示出明显的镇痛作用,并且BVI在热板法和扭体法模型的镇痛作用具有剂量依赖性。在热板法和辐射热法疼痛模型中,BVI于ZT22给药比ZT6给药显示出更强的镇痛作用。蜂毒对疼痛模型小鼠血清β-EP水平未显示上调作用;但可明显降低血清SP含量,且具有ZT22给药低于ZT6给药的昼夜变化(P<0.05);对扭体法和辐射热法(仅ZT22给药组)疼痛模型小鼠血清IL-1β水平显著下调,而在热板法则显示IL-1β水平明显增高。结论:小鼠的痛阈存在峰值在明中后期、谷值在暗后期的昼夜节律;BVI对小鼠多种疼痛模型均具有镇痛作用,且存在昼夜差异;BVI的镇痛作用及其昼夜变化可能与调节内源性疼痛介质有关。展开更多
There is a growing body of evidence showing that periaqueductal gray (PAG) and nucleus accumbens (N. accumbens) play important roles in the modulation of nociception. In our previous study of the mechanisms of morphin...There is a growing body of evidence showing that periaqueductal gray (PAG) and nucleus accumbens (N. accumbens) play important roles in the modulation of nociception. In our previous study of the mechanisms of morphine analgesia we found that opioid antagonist naloxone injected into either of the two nuclei, PAG or N. accumbens, could展开更多
BACKGROUND： The arcuate nucleus, when damaged in young rats, can lead to pathological changes in adults, such as osteoporosis. Ovariectomized rats suffer from osteoporosis at eight weeks following surgery and the num...BACKGROUND： The arcuate nucleus, when damaged in young rats, can lead to pathological changes in adults, such as osteoporosis. Ovariectomized rats suffer from osteoporosis at eight weeks following surgery and the number of β -endorphin immunoreactive neurons in the arcuate nucleus of the hypothalamus is significantly decreased. OBJECTIVE： To establish a rat model of osteoporosis using ovariectomy and to explore changes in the number of β-endorphin neurons and to correlate any such change with serum hormone levels in response to exercise or rest. DESIGN, TIME AND SETTING： The completely randomized block design, neural morphology study was performed at the Key Laboratory of Physiology, Guangdong Medical College, China between March 2004 and January 2005. MATERIALS： Sixteen healthy female rats were selected for ovariectomy. METHODS： Following model establishment, rats were assigned to either rest or exercise groups and each rat was housed individually. Rats in the exercise group underwent an exercise regimen using a treadmill. MAIN OUTCOME MEASURES： Eight weeks following exercise, radioimmunoassay was performed to detect serum growth hormone, estrogen and osteocalcin levels. Immunohistochemistry was used to measure changes in the number of β -endorphin neurons in the arcuate nucleus of the hypothalamus. Changes in bone metabolism were assessed using bone histomorphometry. RESULTS： In the exercise group, the β -endorphin immunoreactive neurons were high in number, darkly stained, and the nucleus was not obvious. In the rest group, the β -endorphin immunoreactive neurons were low in number and lightly stained. The number of β-endorphin immunoreactive neurons in the exercise group was higher compared with the rest group （t = 2.83, P 〈 0.05）. Estrogen levels were similar between the rest and exercise groups （P 〉 0.05）. Serum osteocalcin and growth hormone levels were significantly higher in the exercise group compared with the rest group （t = 2.78, 2.32, P 〈 0.05）. Compared with the rest group, the percentage of trabecular bone area, trabecular thickness, and trabecular number were significantly increased, but trabecular separation was significantly reduced （t=2.48, 2.57, 2.32, 3.06, P 〈 0.05） in the exercise group. In the exercise group, the trabeculae of the tibia were arranged regularly and were high in number. In the rest group, the trabeculae of the tibia were organized in a disorderly manner and were low in number, with many fat particles. CONCLUSION： Exercise promotes bone growth and delays osteoporosis by inducing an increase in the number of β-endorphin immunoreactive neurons in the arcuate nucleus of the hypothalamus and by increasing serum growth hormone and osteocalcin levels.展开更多
文摘Forty rots were randomized into 2 groups and naloxone or saline were injected to therats after they were inflicted with hemorrhagic shock at sea level and at a simulated altitude of4000m respectively to observe the effects of naloxone on left ventricular systolic pressure(LVSP),left ventricular diastolic pressure(LVDP),the maximal changing rate of LVSP(dp/dt max),heartrate(HR),and survival time of the animals.Plasma β-endorphin(β-EP)was determined beforeand after hemorrhage to observe the relationship between β-EP and hemorrhagic shock.It wasfound that the circulatory parameters of hemorrhagic shock changed more markedly at high alti-tude than at sea level,naloxone could restore these parameters and prolong the survival time inboth the animals of the sea level and high altitude groups,and plasma β-EP level was elevatedafter hemorrhage especially in those animals at high altitude.These findings indicate:(1)Hemorrhagic shock at high altitude is usually accompanied with severe clinical manifestations,rapid progression,and high mortality.(2)β-EP seems to participate in the pathologicalmanifestafions of hemorrhagic shock at high altitude,and its depressive action on myocardialcontraction may be one of the factors inducing hemorrhagic shock.(3)Naloxone possesses defi-nite property to comet hemorrhagic shock at high altitude.
文摘We observed for the first time the differences of immunoreactive β-endorphin(IR -β- EP) content in plasma, pituitary and hypothalamus of rats under various conditionsusing radioimmunoassay (RIA) and the effects of naloxone and β - endorphin (β- EP) antiserumon initial time of convulsions (ITC), severity of convulsions(SOC) and mortality on surface(MOS) of rats to hyperbaric oxygen(HBO). The results suggest thatβ- EP may partici-pate in the course of oxygen - induced convulsions and be one of endogenous convulsion - causingagents.
文摘To observe plasm a β-endorphin (β-EP) and gonadotrophin releasing horm one (GnRH), hum an chorionic gonadotrophin (hCG), progesterone (P4) levelsin w om en w ith early threatened abortion and w ith a history of recurrent spontaneous abortions (RSA). Tw enty patientsw ith threatened abortion at7～8 w eeksof gestation w ere re- cruited, allof them had a history of 3 or m ore recurrentunexplained abortions. They w ere treated w ith psychologicalconsultation accompanied by traditionalChinese herbs. Blood samples w ere taken to m easure β-EP, GnRH, hCG and P4 levels by radioim - m unoassay (RIA). The treatm ents w ere continued till10～12 w eeks, blood w astaken during this period to compare changes in these peptides / horm ones. Tw enty norm al pregnantw om en at7～8 and 10～12 w eeksand 20 patientsw ith incompleteabortion at 10～12 w eeksw ererecruited for comparativestudies. Results: (1) In norm alpregnant w om en, plasm a β-EP, GnRH, hCGand P4 levelsat10～12 w eeksw ere significantly higher than thatat7～8 w eeks (P< 0.01). (2) In patients w ith threatened abortion and a history of RSA, plasm a β-EP levels at7～8 w eeks w ere significantly higher than those of norm al pregnantw om en (P< 0.01); on the contrary, plasm a GnRH, hCGand P4 levelsin these patientsw ere significantly low er than thosein norm alcases (P< 0.01). After treatm ent, 16 of the 20 patients succeeded in m aintaining their pregnancies, the levels of the four plasm a contents at10～12 w eeks w ere sim ilar to thosein norm alpregnantw om en (P> 0.05). (3) Plasm a β-EPlevelsin patientsw ith incomplete abortionsat10～12 w eeksw ere dram atically higher and GnRH, hCGand P4 levelsw ere low er than in norm alpregnantw om en (P< 0.01). β-EP m ightplay a role in the pathophysiology of spontaneousabortion.
文摘The effects of opioid peptides on iminune responses were investigated. It was found that β-endorphin (β-END) can depress proliferative responses to PHA in rat splenocytes but enhance those in mice, and it could also inhibit the plaque-forming cell (PFC) response to sheep red blood cells when mouse splenocytes immunized in vivo were cultured in vitro with the peptide. The peptide antagonist naloxone was able to reverse β-END suppression of the PFC response. The data indicate that β-END suppresses antibody production or secretion via a specific opioidreceptor-mediated mechanism.
文摘The effect of electromagnetic field on plasma β endorphin in 30 patients with migraine were studied in the experiment. All subjects received a 20 minute repetitive transcranial magnetic stimulation (Frequency 10Hz, Average intensity 8mT) per time, and the total experiment lasted 20 times. Before and after the experiment, the EEG and plasma β endorphin were tested. The results show that the level of plasma β endorphin in patients blood increased significantly from (73.486±26.002)mg/ml to (116.934±67.592)mg/ml (p<0.01), and the EEG average magnitude of the migraine patients were improved obviously from 41.77μV to 47.42μV.
基金Project supported by the National Natural Science Foundation of China,No.39670896
文摘AIM To study the role of cholecystokinin- octapeptide (CCK-8). β-endorphin (β-EP). and gastrin in an anorexic infantile rat model and no subsequent regulation of nose peptides by the Yunpi complex prescription ErBao Granule. METHODS We fed infantile rats with special prepared forage. A liquid extract of ErBao Granule was administered to the rats daily for 3 weeks, CCK-8, β-EP, and gastrin concentrations in hypothalamus, gastric antrum, and plasma of the rats were measured by radioimmunoassay, and were compared with controls. RESULTS Treatment of rats with ErBao Granule inhibited CCK-8 secretion and increased β-EP and gastrin secretion. CCK-8 concentration in hypothalamus and plasma of model control group increased significantly and correlated negatively with food intake of models, respectively. β-EP concentration in gastric antrum and plasma of model control group decreased significantly and showed a positive correlation with food intake of models, respectively. Hypothalamus concentration of β -EP was similar in models and controls. Gastrin concentration in gastric antrum of models was lower than in the blank control group, and correlated positively to food intake of models. Finally, CCK-8 concentrations in plasma of rats showed a positive correlation with plasma β-EP (r=-0.68, P<0.05). CONCLUSION The increased plasma and hypothalamus concentration of CCK-8, decreased gastric antrum and plasma level of β -EP, and decreased gastric antrum concentration of gastric are associated significantly with the anorexia of infantile anorexic rat models produced by special forage. ErBao Granule can reverse these changes, which may be the major mechanisms of ErBao Granule simulating feeding.
文摘Objective:To evaluate the effectiveness and safety of electroacupuncture in conjunction with additional medications in providing analgesia and stabilizing hemodynamic parameters during total thyroidectomy.Methods:This randomized controlled trial included 100 patients who underwent a total thyroidectomy between October 2022 and October 2023 at the Vietnam National Hospital of Acupuncture.The patients were randomized into two groups.The electroacupuncture analgesia(EA)group received EA stimulation at five acupuncture points:Hegu(LI 4),Neiguan(PC 6),Shuitu(ST 10),Quepen(ST 12),and Yifeng(SJ 17),while the control group received a bilateral superficial cervical plexus block.Primary outcomes included the level of analgesia and perioperative vital signs in both groups.Additionally,pain thresholds and serum b-endorphin levels were measured before and after electroacupuncture in the EA group.Results:Complete analgesia(Level A)was attained in 86%and 76%of the patients in the EA and control groups,respectively,with no significant difference between the two groups(P=1.00).In the EA group,the mean pain threshold after receiving EA doubled(648.7(77.4)g/s vs.305.3(45.3)g/s,P<.001),and the mean serum b-endorphin level increased by approximately 13.5 pg/mL(P<.001).All patients remained hemodynamically stable throughout the surgery.Conclusion:EA,in conjunction with additional medications that stimulate five acupuncture points,LI 4,PC 6,ST 10,ST 12,and SJ 17,was well tolerated and effectively maintained a suitable level of analgesia and hemodynamic stability during total thyroidectomy.
文摘目的:探讨小鼠疼痛模型的昼夜节律和注射用蜂毒(Bee venom for injection,BVI)镇痛作用的昼夜差异及其相关机制。方法:采用热板法、辐射热甩尾法建立小鼠疼痛模型,在6个授时(Zeitgeber time,ZT)时间点(ZT2、ZT6、ZT10、ZT14、ZT18、ZT22)测量痛阈并分析其昼夜节律。将合格昆明小鼠随机分为注射用蜂毒大剂量(Bee venom for injection-High dose,BVI-H)、注射用蜂毒中剂量(Bee venom for injection-Medium dose,BVI-M)、注射用蜂毒低剂量(Bee venom for injection-low dose,BVI-L)、吗啡(Morphine,MOR)和模型(Model,MOD)组;每组再根据小鼠痛阈的昼夜节律分为两个亚组,分别在痛阈的峰值和谷值2个时间点给药。观察各组对热板法、辐射热甩尾法和扭体法疼痛模型小鼠行为学影响的动态变化;ELISA法检测血清P物质(Substances P,SP)、β-内啡肽(Beta-endorphin,β-EP)和IL-1β(interleukin-1β,IL-1β)水平。结果:小鼠疼痛模型的痛阈显示出峰值在明中期(ZT6)、谷值在暗后期(ZT22)的昼夜节律。BVI三个剂量组和MOR组均显示出明显的镇痛作用,并且BVI在热板法和扭体法模型的镇痛作用具有剂量依赖性。在热板法和辐射热法疼痛模型中,BVI于ZT22给药比ZT6给药显示出更强的镇痛作用。蜂毒对疼痛模型小鼠血清β-EP水平未显示上调作用;但可明显降低血清SP含量,且具有ZT22给药低于ZT6给药的昼夜变化(P<0.05);对扭体法和辐射热法(仅ZT22给药组)疼痛模型小鼠血清IL-1β水平显著下调,而在热板法则显示IL-1β水平明显增高。结论:小鼠的痛阈存在峰值在明中后期、谷值在暗后期的昼夜节律;BVI对小鼠多种疼痛模型均具有镇痛作用,且存在昼夜差异;BVI的镇痛作用及其昼夜变化可能与调节内源性疼痛介质有关。
文摘There is a growing body of evidence showing that periaqueductal gray (PAG) and nucleus accumbens (N. accumbens) play important roles in the modulation of nociception. In our previous study of the mechanisms of morphine analgesia we found that opioid antagonist naloxone injected into either of the two nuclei, PAG or N. accumbens, could
文摘BACKGROUND： The arcuate nucleus, when damaged in young rats, can lead to pathological changes in adults, such as osteoporosis. Ovariectomized rats suffer from osteoporosis at eight weeks following surgery and the number of β -endorphin immunoreactive neurons in the arcuate nucleus of the hypothalamus is significantly decreased. OBJECTIVE： To establish a rat model of osteoporosis using ovariectomy and to explore changes in the number of β-endorphin neurons and to correlate any such change with serum hormone levels in response to exercise or rest. DESIGN, TIME AND SETTING： The completely randomized block design, neural morphology study was performed at the Key Laboratory of Physiology, Guangdong Medical College, China between March 2004 and January 2005. MATERIALS： Sixteen healthy female rats were selected for ovariectomy. METHODS： Following model establishment, rats were assigned to either rest or exercise groups and each rat was housed individually. Rats in the exercise group underwent an exercise regimen using a treadmill. MAIN OUTCOME MEASURES： Eight weeks following exercise, radioimmunoassay was performed to detect serum growth hormone, estrogen and osteocalcin levels. Immunohistochemistry was used to measure changes in the number of β -endorphin neurons in the arcuate nucleus of the hypothalamus. Changes in bone metabolism were assessed using bone histomorphometry. RESULTS： In the exercise group, the β -endorphin immunoreactive neurons were high in number, darkly stained, and the nucleus was not obvious. In the rest group, the β -endorphin immunoreactive neurons were low in number and lightly stained. The number of β-endorphin immunoreactive neurons in the exercise group was higher compared with the rest group （t = 2.83, P 〈 0.05）. Estrogen levels were similar between the rest and exercise groups （P 〉 0.05）. Serum osteocalcin and growth hormone levels were significantly higher in the exercise group compared with the rest group （t = 2.78, 2.32, P 〈 0.05）. Compared with the rest group, the percentage of trabecular bone area, trabecular thickness, and trabecular number were significantly increased, but trabecular separation was significantly reduced （t=2.48, 2.57, 2.32, 3.06, P 〈 0.05） in the exercise group. In the exercise group, the trabeculae of the tibia were arranged regularly and were high in number. In the rest group, the trabeculae of the tibia were organized in a disorderly manner and were low in number, with many fat particles. CONCLUSION： Exercise promotes bone growth and delays osteoporosis by inducing an increase in the number of β-endorphin immunoreactive neurons in the arcuate nucleus of the hypothalamus and by increasing serum growth hormone and osteocalcin levels.
