Midbrain enkephalin expression in a rat migraine model following intragastric scorpion powder administration

Scorpion has strong analgesic effects, but its analgesic mechanisms remain unclear. This study investigated the effects of scorpion powder on enkephalin expression in the midbrain of rats with nitroglycerin-induced migraine at mRNA and protein levels. Results confirmed that migraine rat abnormal behavior was significantly improved, and proenkephalin mRNA expression was significantly increased following treatment with scorpion. The number of methionine-enkephalin- positive cells in the migraine rats following treatment with scorpion was significantly increased, but no significant difference in the number of leucine-enkephalin-positive cells was detectable compared with migraine and normal rats. Taken together, these results show that scorpion exerts potentially beneficial effects by promoting enkephalin expression in nitroglycerin-induced migraine rats.

Effects of Toutongning capsule on enkephalin expression in a rat migraine headache model

Toutongning capsule is used for the treatment of migraine headaches, and has yielded therapeutically beneficial effects. However, whether Toutongning capsule exerts its effects via endogenous opioid peptides remains poorly understood. This study investigated the effects of Toutongning capsule on enkephalin expression in the midbrain of rats with nitroglycerin-induced migraine headache at the mRNA and protein levels. Results confirmed that proenkephalin mRNA levels were significantly upregulated following treatment with Toutongning capsule. The numbers methionine-enkephalin and leucine-enkephalin-positive cells were significantly greater in the migraine headache rats following treatment with Toutongning capsule compared with the model group. Taken together, these results show that Toutongning capsule exerts potentially beneficial effects by promoting enkephalin expression in nitroglycerin-induced migraine headache rats.

Serotonin样,Substance P样,Enkephalin样反应阳性神经元胞体在大鼠中缝核簇内的分布

本文用PAP法研究了Serotonin样,Substance P样,Leucine—Enkephalin样和Methionine—Enkephalin样反应阳性神经元胞体在大鼠中缝核簇内的分布。证明Serotonin存在于中缝苍白核、中缝隐核、中缝大核、中缝桥核、中央上核和中缝背核等处的某些神经元胞体内。以中、小细胞为主,在中缝大核内有少数大细胞。细胞形态为梭形、圆形、卵圆形以及多极细胞。Substance P样反应阳性胞体在上述中缝核内也被发现,其胞体的大小、形态和分布与serotonin样反应阳性胞体相似,但数目稍少。Leucine—Enkephalin样反应阳性胞体存在于中缝苍白核、中缝隐核、中缝大核、中缝桥核、中缝背核和中央上核内,但Methionine—Enkephalin样反应阳性细胞体仅在中缝苍白核和中缝隐核的吻侧部以及中缝大核内发现。后两者均以大,中型多极细胞为主。

EFFECTS OF ACUPUNCTURE ON THE CONTENTS OF ENKEPHALINS IN DIFFERENT BRAIN REGIONS AND CORTICOSTERONE IN PLASMA OF RATS WITH ENDOTOXIN SHOCK

In this experiment,we have observed the effects of acupuncture on the contents ofenkephalins in different brain regions and corticosterone in plasma of rats with endotoxin shock.Theresults showed that after acupuncture the endogenous enkephalins were significantly decreased(P【0.05)in the midbrain and brain stem of endotoxin shock rats,suggesting the anti-shock of acupuncture might be related to the enkephalins in the midbrain and brain stem.In addition,there was a rising trend in plasma corticosterone of the rats with toxic shock.

Analgesic action of suspended moxibustion in rats with chronic visceral hyperalgesia correlates with enkephalins in the spinal cord

Rats that modeled chronic visceral hyperalgesia received suspended moxibustion at bilateral Tianshu （ST25） and Shangjuxu （ST37） once daily over a period of 7 days. Results show that suspended moxibustion significantly depressed abdominal withdrawal reflex scores and increased enkephalin concentration in the spinal cord. The experimental findings suggest that spinal enkephalins contributed to the analgesic effect of suspended moxibustion in rats with chronic visceral hyperalgesia.

Conceptual Density Functional Theory Study of the Chemical Reactivity Properties and Bioactivity Scores of the Leu-Enkephalin Opioid Peptide Neurotransmitter

The SMD solvation model (Solvation Model based on the Density) and eight density functionals, CAM-B3LYP, LC-ωPBE, M11, MN12SX, N12SX, ωB97, ωB97X, and ωB97XD, were assessed in link with the Def2TZVP basis set for the calculation of the structure of the Leu-Enkephalin Opioid Peptide Neurotransmitter as well as their molecular properties. Through the Conceptual Density Functional Theory (CDFT), the entire chemical descriptors for the system were calculated. The active regions of the molecules necessary for electrophilic, nucleophilic and radical attacks were chosen through linking them with the corresponding Fukui functions. Furthermore, the prediction of the pKa value for the peptide is done with great accuracy as well as the ability of the studied molecule in acting as an efficient inhibitor of the formation of Advanced Glycation Endproducts (AGEs), which comprises of a useful knowledge for the development of drugs for preventing Alzheimer, Diabetes and Parkinson diseases. Lastly, the bioactivity scores for the studied peptides are predicted via various methodologies.

[D-Pen^2,D-Pen^5]enkephalin及Nor-binaltorphimine对吗啡损害小鼠自主选择能力的影响

选择性δ阿片受体激动剂[D-Pen^2,D-Pen^5]enkephalin(DPDPE),k阿片受体拮抗剂nor-bindtorphimine(N-BNI)在测试剂量下对小鼠在丫形迷宫中的自主选择能力无明显影响,但均可显著增强吗啡损害小鼠自主选择能力的作用。DPDPE对吗啡的协同作用还可被δ阿片受体拮抗剂ndltrindole(NTI)所拮抗。

Plasma leucine enkephalin content in patients with “Liver-blood deficiency” syndrome and clinical significance

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Effects of electric field stimulation on endogenous enkephalin content in artery wall

After 20min electric field stimulation,L-enkephalin （L-ENK） content in the rabbitear artery declined from the control value of 38.99±17.29 to 12.55±1.96pg/mg of wet tissue（n=12）,and M-enkephalin （M-ENK） content from 134.67±8.11 to 73.68±17.96pg/mg of wet tis-sue （n=6）,both being significantly decreased.This effect was not influenced after blockade ofadrenergic receptor by yohimbine.Contractions of artery strips induced by electric field stimulationwere enhanced distinctly after pretreatment of the artery strips with naloxone,an opioid receptorblocker,and with pronase,but not after pretreatment with trypsin.The results suggested that the re-lease of endogenous enkephalins in the ear artery could be induced by electric field stimulation andx2-receptor might not participate in the release course,The release amount of ENK from the ar-terv strips increased when the stimulus freduency increased within the range of 2 Hz to 8 Hz.

Effects of methionine enkephalin on immune enhancement by reducing myeloid derived suppressor cells and reprogramming liver metabolism in colon cancer mice

OBJECTIVE To investigate enhanced immune function of methionine encephalin(MENK)and its anti-tumor mechanism in CT26 colon cancer mouse model.METHODS 3×10~6CT26 cells were implanted subcutaneously in BALB/c mice.Four days after,MENK was peritoneally administrated at the concentration of 20 mg·kg^(-1) for 14 d.The percentage of MDSCs in bone marrow,spleen,blood,tumor and liver were detected by flow cytometry.Non-esterified fatty acid(NEFA),triglycerides(TG)and total cholesterol(T-CHO)in liver homogenate were tested by a NEFA test kit,a TG test kit and a T-CHO test kit respectively.qRT-PCR and Western blot were used to measure m RNA and protein levels of inflammation-,glycometabolsim-and lipometabolsim-associated indexes in liver.RESULTS MENK decreased percentages of MDSCs in bone marrow,spleen,blood and tumor in colon cancer mice.MENK-treated mice displayed elevated ratio of CD4^+T and CD8^+T cells in spleen as well as increased T and B lymphocytes proliferation.Meanwhile,MENK also ameliorated liver damage reflected by lower levels of GPT and GOT in serum and reduced risks of cancer-associated index including inflammation,high lipid and high glucose.Furthermore,MENK lowered down the levels of NEFA,TG and T-CHO in liver homogenate.MENK treatment decreased expression of p-STAT3,increased expression of p-AKT,IRS1 and Glut4 at protein level as well as reduced lipogenesis-associated genes and elevated glycolysis-associated genes in liver of tumor bearing mice.Also,abated expression of genes associated with MDSCs generation(M-CSF,GM-CSF,IL-6,IL^(-1)β)and migration(S100A9,KC)was observed within shrunken subcutaneous tumor by MENK intervention.CONCLUSION MENK has the ability to strength immune function against colon cancer by reducing MDSCs and improving liver metabolism.

EFFECT OF METHIONINE ENKEPHALIN ON MIGRATION OF MACROPHAGES FROM MICE WITH IMPAIRED LIVER

Objective To observe the effects of methionine enkephalin (M Enk) on migration of macrophages from mice with impaired liver and its immunomodulatory mechanisms. Methods Liver of mice was impaired by feeding CCl 4 and macrophage migration inhibitory factor (MMIF) was produced by Con A stimulated spleen lymphocytes. Inhibition of macrophage migration was measured in reaction system by adding M Enk. Results Migration of macrophages in both liver impaired and control group were suppressed by MMIF, but the suppression might be reversed by adding 1 μmol/L M Enk ( P <0.05).M Enk could significantly inhibit in vitro both of the combination of MMIF with macrophages and production of MMIF from lymphocytes ( P <0.01).Macrophages from liver imparied group showed a higher sensitivity compared to the control group ( P <0.05).Conclusion The study suggests that opioid peptieds play an important role in the modulation of the immune response under stress as liver impairment.

Effect of Intracerebral Injection of Substance P on Pain Threshold,Electroacupuncture Analgesia and Met-enkephalin Level in Rat Brain

Radioimmunoassay was employed to dctermine the immunorcactivc met-enkephalin(ir-MEK)contents of several brain regions .The pain threshold(PT)andir-MEK content of striatum and hypothalamus increased markedly afterintraoerebroventricular injection of substance P(SP)in the dosage of lμgg/10μl ,but nosignificant change of ir-MEK content in hippocampus was observed.When theperiaqueductal gray(PAG)was destroyed with electrolysis,the increase of PT andir-MEK content in the two brain regions after SP injection was obviouslysuppressed(P【0.05-0.01).The PT and ir-MEK content of hypothalamus andstriatum would also increase after intra-PAG injection of SP(0.4μg/4μl),electroacupuncture or intraperitoneal injection of morphine.The ir-MEK content ofhippocampus could also increase after intra-PAG injection of SP or intraperitoncal injec-tion of morphine.The combination of intra-PAG injection of SP andelectroacupuncture caused a more marked elevation of PT and ir-MEK content of the 3brain regions than either of the two used singly could(P【0.01 ).The combined effect ofintra-PAG injection of SP and intraperitoneal injection of morphine was similar to thatof either of the two used singly(P】0.05).These facts indicate that thc analgesic effect ofSP activated by PAG was mediated through the increase of cerebral met-cnkcphalin con-tent,and there was a synergic effect between SP and elcctroacupuncturc.

Distribution，content and action site of leucine－enkephalin in pulmonary artery wall out of lung

When immunohistochemical method was used to investigate the distribution of peptidergic fibers in the pulmonary artery wall of SD rat, L-enkephalin immunoredetive (L-ENK) fibers were easily demonstrated. The contents of L-ENK in pulmonary artery of rat an

RELATIONSHIP BETWEEN ACUPUNCTURE ANALGESIA AND MET-ENKEPHALIN OR DYNORPHIN

subjective: The effect of 4～5 Hz electroacupuncture (EA) on alterations of both met enkephalin (MEK) and dynorphin (Dyn) in the patient plasma or mouse spinal cord and its relation with analgesic effect were studied.Methods: In acupuncture clinic 10 patients with acute pain were treated with 4 Hz EA at Zusanli(ST 36) and/or Hegu(LI 4) acupoints for 30 min. 20 BALB/C mice were randomly divided into 2 groups: a. EA group(n=10), treated with 4～5 Hz EA at bilateral “Zusanli"(ST 36) for 15 min; b. control group(n=10) treated with no EA, but also restrained for 15 min. Before and after EA or restraining acupoints, the pain threshold of the patients or mice was detected. 10 μl of the patient plasma before and after EA and each mouse spinal cord suspension, of the 2 groups were blotted onto nitrocellulose membrane (NCM) respectively. The protein dot blot signals were detected by immunoreactivity (IR) and using Shimadu TLC Scanner and analyzed statistically. Results: The results showed that an increase in patient plasma MEK IR or Dyn IR and a decrease in mouse spinal MEK IR or Dyn IR could be detected, and the alteration of plasma or spinal MEK IR was more significant than that of plasma or spinal Dyn IR. There was a positive correlation in alteration between plasma or spinal MEK IR and plasma or spinal Dyn IR with respective parallel levels in individuals. The increased plasma MEK IR or the decreased spinal MEK IR was positively or negatively correlated with the analgesic effect, while the correlation between plasma or spinal Dyn IR and analgesic effect was insignificant. Conclusion: The results suggest that under lower frequency EA the met enkephalin may play an important role in analgesia.

Endogenous enkephalin does not contribute to the cerebral anti-hyperalgesic action of gabapentin

The aim of this study was to investigate the role of endogenous enkephalin in the cerebral antihyperalgesic action of gabapentin.Neuropathic pain models and antihyperalgesic effect of gabapentin were confirmed by the presentation and changes of mechanical allodynia and thermal hyperalgesia of operated mouse hind paws.The results suggested that endogenous enkephalin may not be involved in the antihyperalgesic effect of gabapentin.

Immunomodulating effects of methionine enkephalin

甲硫氨酸脑啡肽（ＭｅｔＥｎｋ）在神经免疫内分泌调节网络中的作用引起广泛关注．作者等实验证明它能使ＬＰＳ刺激的小鼠腹腔巨噬细胞产生ＩＬ１，纳洛酮不能阻止这种作用．ＭｅｔＥｎｋ促进小鼠脾淋巴细胞增殖和ＩＬ２、ＩＬ６的产生，这种上调作用与增强此二种白细胞介素ｍＲＮＡ转录并提高其稳定性有关．因此ＭｅｔＥｎｋ在增强前炎性细胞因子表达方面是一个重要的免疫调节信号分子．

THE INTERACTION BETWEEN PERIAQUEDUCTAL GRAY AND NUCLEUS ACCUMBENS IN ACCELER-ATING THE RELEASE OF ENKEPHALINS AND β-ENDORPHIN

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

DEPRESSION OF RETRIEVAL OF AN OPERANT CONDITIONING IN RATS BY ENKEPHALIN

It is established that opioid peptides are involved in the regulation of various physiological processes including the higher function of the brain. We have reported that peripheral administration of enkephalin impaired memory retention in mice. This effect was reversed by naloxone. We further found that bestatin, an aminopeptidase inhibitor, when injected peripherally or into amygdala introduced memory impairment which mimiced the effect of enkephalin. The present study examined the influence of hippocampal and peripheral enkephalin on operant defence conditioning in rats, with an attempt to detect the action of central enkephalin on memory.

Construction and identification of immortalized rat astrocyte cell line expressing enkephalin

Objective:To provide a sound cell source for further ex-vivo gene therapy for chronic pain,we attempt to develop an immortalized rat astrocyte cell line that expresses enkephalin regulated by doxycycline. Methods:Retrovirus infection method was employed to develop an immortalized rat astrocyte cell line that could express enkephalin regulated by doxycycline.The hPPE gene expression level of immoralized astroyte cells(IAC)/ hPPE was detected by RT-PCR,indirect immunofluorescence staining and radioimmunoassay. Results:IAC carrying Tet-on system transfected with preproenkephalin gene could secrete enkephalin that was regulated by doxycycline in a dose-dependent manner and hPPE gene activation could be repeated in on-off-on cycles through administration or removal of doxycycline. Conclusion:An immortalized rat astrocyte cell line that secrete enkephalin under the control of doxycycline is established successfully,which provides a research basis for transgenic cell transplantation for analgesia.

EFFECT OF ENDOGENOUS LEU-ENKEPHALIN ON ACUPUNCTURE IMMUNE RESPONSE

Acupuncture can modulate immune responses and thus produce good therapeutical results when used as an subsidiary measure to treat some infectious diseases, tumors and unbalanced immune functions. ZHAO et al. held that endogenous opiates participate in the modulation of immune responses by acupuncture. It has been reported abroad