Muscle unloading due to long-term exposure of weightlessness or simulated weightlessness causes atrophy, loss of functional capacity, impaired locomotor coordination, and decreased resistance to fatigue in the antigravity muscles of the lower limbs. Besides reducing astronauts' mobility in space and on returning to a gravity environment, the molecular mechanisms for the adaptation of skeletal muscle to unloading also play an important medical role in conditions such as disuse and paralysis. The tail-suspended rat model was used to simulate the effects of weightlessness on skeletal muscles and to induce muscle unloading in the rat hindlimb. Our series studies have shown that the maximum of twitch tension and the twitch duration decreased significantly in the atrophic soleus muscles, the maximal tension of high-frequency tetanic contraction was significantly reduced in 2-week unloaded soleus muscles, however, the fatigability of high-frequency tetanic contraction increased after one week of unloading. The maximal isometric tension of intermittent tetanic contraction at optimal stimulating frequency did not alter in 1- and 2-week unloaded soleus, but significantly decreased in 4-week unloaded soleus. The 1-week unloaded soleus, but not extensor digitorum longus (EDL), was more susceptible to fatigue during intermittent tetanic contraction than the synchronous controls. The changes in K+ channel characteristics may increase the fatigability during high-frequency tetanic contraction in atrophic soleus muscles. High fatigability of intermittent tetanic contraction may be involved in enhanced activity of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) and switching from slow to fast isoform of myosin heavy chain, tropomyosin, troponin I and T subunit in atrophic soleus muscles. Unloaded soleus muscle also showed a decreased protein level of neuronal nitric oxide synthase (nNOS), and the reduction in nNOS-derived NO increased frequency of calcium sparks and elevated intracellular resting Ca2+ concentration ([Ca2+]i) in unloaded soleus muscles. High [Ca2+]i activated calpain-1 which induced a higher degradation of desmin. Desmin degradation may loose connections between adjacent myofibrils and further misaligned Z-disc during repeated tetanic contractions. Passive stretch in unloaded muscle could preserve the stability of sarcoplasmic reticulum Ca2+ release channels by means of keeping nNOS activity, and decrease the enhanced protein level and activity of calpain to control levels in unloaded soleus muscles. Therefore, passive stretch restored normal appearance of Z-disc and resisted in part atrophy of unloaded soleus muscles. The above results indicate that enhanced fatigability of high-frequency tetanic contraction is associated to the alteration in K+ channel characteristics, and elevated SERCA activity and slow to fast transition of myosin heavy chain (MHC) isoforms increases fatigability of intermittent tetanic contraction in atrophic soleus muscle. The sarcomeric damage induced by tetanic contraction can be retarded by stretch in atrophic soleus muscles.
Animals ; Calcium Signaling ; Calpain ; metabolism ; Desmin ; metabolism ; Muscle Contraction ; Muscle Fatigue ; Muscle, Skeletal ; physiopathology ; Muscular Atrophy ; physiopathology ; Myosin Heavy Chains ; metabolism ; Rats ; Sarcoplasmic Reticulum ; pathology ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; metabolism ; Weightlessness Simulation

In recent years, according to the etiology and pathology researches of slow transit constipation (STC) STC is considered as a kind of "enteric neuropathy", indicating it is a kind of disease caused by abnormity of the enteric nervous system (ENS). Through reviewing the mechanism of acupuncture to regulate STC, it is found out that there is a close relationship between acupuncture regulating STC and ENS. Through various channels including ganglion cells, nerve plexus, neurotransmitter and TRPV1 (the primary sensory neurons receptor of the ENS) of the ENS, acupuncture is likely to make comprehensive adjustment on STC.
Acupuncture Therapy ; Colon ; innervation ; physiopathology ; Constipation ; physiopathology ; therapy ; Enteric Nervous System ; physiopathology ; Humans

This article was aimed to observe the intracardiac pressure under different states by electric acupuncture (EA) on yuan-source point of PC7-Daling and to explore the acupuncture effect features. Catheterization was applied through the right common carotid artery to the left ventricle in order to record the left intraventricular pressure. The intracardiac pressure was used as an indicator. The effects of EA on PC7-Daling to the left intraventricular pressure of rats were observed under the states of normal physiology, isoproterenol and propranolol, respectively. The results showed that for the immediate effects of acupuncture, EA on PC7-Daling can obviously excited the intracardiac pressure of normal rats. Under the state of intravenous application of propranolol and isoproterenol, no obvious reac-tions during EA on PC7-Daling. From the effects of acupuncture, under normal conditions, EA on PC7-Daling had excitatory effect; under propranolol state, it had inhibitory effects; and the effect of isoproterenol state was variable. It was concluded that according to the specificity of acupoint effect, PC7-Daling can excite intracardiac pressure.

OBJECTIVETo observe the intestinal movement of transient receptor potential vanilloid 1 or vanilloid receptor 1 (TRPV1) knockout mice after stimulated by electroacupuncture (EA), and to primarily explore the roles of TRPV1 receptor in the jejunal motility regulated by acupuncture.

METHODSNormal wild-type CL57BL/6 and TRPV1 gene knockout mice were recruited in two groups, the B6 group and the TRPV1 group, 15 in each group. The thermal threshold and the mechanical pain threshold were respectively detected using JL-F digital photo thermal analyzer instrument and ALMEMO2450 machine. The difference between the two thresholds were compared. Meanwhile, a self-made pressure head was placed in the jejunum. The internal pressure was monitored. When the pressure was stable, 2 mA 2/15 Hz EA at Quchi (LI11), Tianshu (ST25), Shangjuxu (ST37), and Dachangshu (BL25) to observe the changes of intestinal pressure value between before and after EA. The curve of internal pressures was recorded.

RESULTS(1) The stimulation of light/heat and mechanical stimulation were obviously slowed in the TRPV1 group than in the B6 group (P < 0.01). (2) In the intestinal pressure observation experiment, the bowel movement was not obviously seen in the two groups when acupunctured at Quchi (LI11) and Shangjuxu (ST37) (P > 0.05). (3) Acupuncture at Tianshu (ST25) and Dachangshu (BL25) of TRPV1 knockout mice could lead to intestinal movement (P < 0.05), mainly inhibited bowel movement. The changing degree was equivalent to that of B6 mice.

CONCLUSIONSUnder the physiological condition, TRPV1 might be mediated by thermal and mechanical stimulation. But TRPV1 mediated acupuncture effect was quite complex, indicating TRPV1 mice might be one of intestinal movement mediating factors.

Animals ; Electroacupuncture ; Gastrointestinal Motility ; Jejunum ; physiology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; TRPV Cation Channels ; physiology

Objective To study the preventive and therapeutic effects of ginkgo biloba extract 761 on disused skeletal muscle atrophy by observing its effects on the wet weight, protein content and contraction of the gastrocnemius of fixed hindlimb in rats. Methods 24 SD rats were divided into blank group, contrast group and experimental group. Their right hind limbs were fixed for 4 weeks with plastic plaster from metatarsus to 1 cm up the knee. The knee joint was fixed in 100? flexion and the ankle joint in 60? plantar flexion. Rats in the contrast group were perfused with 3mL distilled water, and rats in the experimental group were perfused with ginkgo biloba extract 761 (120 mg/kg, 14 mg/mL). The whole gastrocnemius muscle of the right hindlimb was dissected 4 weeks later to measure its contract tension, wet weight and protein content. Results Compared with the blank group, single maximal contraction, maximal tetanus, wet weight and protein content of the gastrocnemius muscle in the contrast and experimental groups decreased significantly (P

OJECTIVETo explore whether different acupuncture signals were afferent to the cerebellar fastigial nucleus (FN) neuron and to find out their corresponding effect features through observing the effect of spontaneous discharge of cerebellar FN neuron by needling at different acupoints.

METHODSTotally 120 male SD rats were anesthetized by 20% urethane and their right cerebellar FN were positioned (AP 11. 6 mm, RL 1. 0 mm, H 5. 6 mm). Extracelluar discharge was recorded by glass microelectrode (AP: -11. 6 mm, R: 1. 0 mm, H: 5.7 -7. 0 mm), using extracellular microelectrode recording method, recording the spontaneous discharge of cerebellar FN neurons as a baseline. Random order of needling at zusanli (ST36), quchi (Lil1), weishu (BL21), and zhongwan (CV12) were compared with the baseline before each acupuncture. Their effects on the discharge of cerebellar FN neurons were observed and compared with baselines.

RESULTSThe frequency of FN neuronal discharge could be elevated by needling at zusanli (ST36), quchi (LiI), weishu (BL21), and zhongwan (CV12) (P <0. 01, P <0. 05). The response rate of needling at Zhongwan (CV12, 56. 00%) was higher than that of needling at Zusanli (ST36), Quchi (Ll1), and Weishu (BL21) (35. 00%, 34. 62%, 36. 63%, respectively) with statistical difference (P <0. 05). The response rate of needling at zhongwan (CV12) was obviously higher than that of needing at other points (F = 2. 101, P < 0. 05).

CONCLUSIONSNeedling at zusanli (ST36 ), quchi (Lil), weishu (BL21), and zhongwan (CV12) could elevate the spontaneous discharge frequency of cerebellar FN neurons. Needling at Zhongwan (CV12) had advantageous roles in regulating cerebellar FN.

Acupuncture Points ; Acupuncture Therapy ; Animals ; Cerebellar Nuclei ; physiology ; Male ; Microelectrodes ; Neurons ; Rats ; Rats, Sprague-Dawley

ObjectiveTo discuss the role of transient receptor potential vanilloid 1 (TRPV 1) in the regulation effect of electroacupuncture on gastric motility.MethodTRPV1 gene knock-out mice (KO mice) and wild-type C57BL/6 mice (WT mice) were selected to receive acupuncture at Zusanli (ST36),Quchi (LI11), Zhongwan (CV12), and Weishu (BL21), and the intragastric pressure was observed before and after acupuncture.ResultElectroacupuncture at Zusanli caused both excitation and inhibition in WT mice, predominated by mild excitation, while electroacupuncture at Weishu, Quchi and Zhongwan all caused inhibition effect; in the KO mice, electroacupuncture at Zusanli, Quchi, Zhongwan, and Weishu all inhibited gastric motility.Conclusion TRPV1 bears certain regulating effect on gastric motility, andacupuncture can inhibit the gastric motility in TRPV gene KO mice.

BackgroundCataract is a leading blinding eye disease,and the prevalence of cataract varies in different regions.ObjectiveThe present study was to investigate the incidence of cataract,surgical coverage rate of cataract and postoperative visual acuity,and to propose a strategy for blindness prevention in Chifeng Keshiketengqi.Methods This is a cross-sectional survey of research.A random cluster sampling method was performed in 12 populated areas in Keshiketengqi.Inhabitants over 50 years in the region were included in this survey.This study was approved by the Ethic Committee of Inner Mongolia People' s Hospital.Informed consents were obtained orally from all the subjects.Disease history,visual acuity,intraocular pressure and regular ophthamological examinations were performed.The inclusion criteria of a pilot study and detailed protocol were employed to calculate the incidence rate of cataract.The questionnaire survey was simultaneously adopted to analyze the cataract-related factors.The surgical coverage rate of cataract in this area was calculated.ResultsIn a total 4234 inhabitants,3826 subjects participated in the survey with a response rate of 90.36％.Cataract was found in 1200 participants with an incidence rate of 31.39％.Age,the female gender and illiteracy were identified as risk factors for cataract (x2 =101.005,P =0.000 ;x2 =58.853,P =0.000 ;x2 =12.037,P =0.007 ).The prevalence rates of cataract were 36.98％ and 33.56％ for illiterates and women,respectively.The incidence rate in the Mongol population was significantly higher than that of the Han population ( 34.83％ vs.29.76％ ) (x2 =9.734,P =0.001 ).The cataract surgery rate increased yearly since 1998.When the vision acuity of the fellow eye was ＜0.1,the surgery coverage rate was 20.60％,but the rates were lower in female,illiterates and the Mongol population (x2 =1.993,P =0.038 ;x2 =16.463,P =0.044 ;x2 =8.523,P =0.029).When a pinhole visual acuity of ＜0.05 was determined as the criteria of blindness,the surgical coverage rate was 28.36％.The cataract surgical coverage rates for Han and Mongolian were 30.67％ and 24.53％,respectively,with a significant difference between them (x2 =12.951,P=0.000).The social burden rate was 3.34％ in this area,with a majority of females,illiterates and the Mongol population ( P＜0.05 ).ConclusionsIn agricultural and pastoral areas of Chifeng Keshiketengqi,the ≥50 years old population has a high rate of cataract blindness and low surgery coverage rate.Surgery is still the preferred way for cataract treatment.

AIM: To investigate the status of myopia in students from different kinds of schools in Shantou city, China.
METHODS: In this cross-sectional study, 2 418 students from 4 middle and high schools in Shantou were surveyed through randomized cluster sampling. Ophthalmic examination and auto-refraction were performed for all subjects.
RESULTS: Among all 2 394 students examined. The myopia rates for students from middle and high school were 48. 07% and 68. 28%. In normal middle school, students from rural area had lower rate of myopia than students from the urban area (χ2 = 13. 879, P<0. 01 ). Students from key rural high schools had lower rate of myopia than students from key urban high school (χ2 =175. 231, P<0. 01).
CONCLUSION:The prevalence of myopia in the middle school of urban area in Shantou was higher than rural area. The increasing rate of myopia in youngsters is correlated with study stress. In order to decrease the myopia rate, it is extremely important to improve study environment in students.

Endothelial and neuronal nitric oxide synthases (eNOS and nNOS) are constitutively expressed in cardiomyocytes under the physiological condition, while inducible nitric oxide synthase (iNOS) is only expressed in cell stress. Nitric oxide (NO) derived from the constitutive isoforms of eNOS and nNOS plays four kinds of inhibitory effects on the myocardium: reducing the contractile frequency of cardiomyocyte, slightly attenuating cardiac contractility, accelerating relaxation and increasing distensibility of cardiomyocyte, and slightly inhibiting mitochondrial respiration and improving the efficiency of myocardial oxygen consumption. In conditions of enhanced cardiac reserve and cardiac hypertrophy, NO derived from eNOS, which forms a complex with a certain kind of receptor on the sarcolemma, modulates receptor-mediated signaling and generates an "accentuated antagonism" by moderate inhibition of cardiac contractility. NO derived from the complex of nNOS-ryanodine receptor (RyR) stabilizes RyR calcium release and increases the efficiency of Ca(2+) cycling in sarcoplasmic reticulum by the inhibitory effects. However, besides the above-mentioned inhibitions of NO derived from eNOS and nNOS, NO derived from iNOS generally prevents mitochondrial permeability transition pore opening by inhibiting mitochondrial respiration under the conditions of the myocardial ischemia-reperfusion injury and heart failure. Therefore, both in the physiological condition and in the pathological condition, NO exhibits a moderate inhibition in cardiac function, and eventually produces cardioprotection.
Animals ; Cardiotonic Agents ; Depression, Chemical ; Humans ; Mitochondria, Heart ; metabolism ; Mitochondrial Membrane Transport Proteins ; physiology ; Myocardial Contraction ; physiology ; Myocytes, Cardiac ; enzymology ; Nitric Oxide ; physiology ; Nitric Oxide Synthase ; metabolism ; Oxygen Consumption ; physiology ; Ryanodine Receptor Calcium Release Channel ; physiology