visualizing-morphological-characteristics-neuromuscular-junction-rat

Visualizing the Morphological Characteristics of Neuromuscular Junction in Rat Medial Gastrocnemius Muscle

The neuromuscular junction (NMJ) is a complex structure serving for the signal communication from the motor neuron to the skeletal muscle and consists of ...

China Academy of Chinese Medical Sciences

China Academy Of Chinese Medical Sciences

The purpose of this study was to determine the cardioprotective effects of the repetitive pretreatment of acupuncture in rats with myocardial ischemia and reperfusion (MIR). Experimental MIR was produced by ligating and reperfusing the left anterior descending coronary artery in the rats. The elevated ST segments of electrocardiogram (ECG), cardiac arrhythmias, and ratio of infarct size/risk zone were compared among the normal control (NC), ischemia and reperfusion (IR), electro-acupuncture (EA), electro-acupuncture plus propranolol (EAP), and EA at nonacupoint (EAN) groups. Before the experiment, EA was applied at bilateral Neiguan acupoints (PC6) in the forelimbs in EA and EAP groups for 30 min once a day for 3 consecutive days. In the EAN group, the same EA treatment was administered at bilateral nonacupoints in the hind limbs. In the EAP group, propranolol, a nonspecific antagonist of beta-adrenoceptors, was administered intraperitoneally 15 min before each EA pretreatment. The results showed that the elevated ST segment of ECG, cardiac arrhythmia score, and ratio of infarct size/risk zone were significantly attenuated in the EA group when compared with those in the IR group (P < 0.05), indicating a cardioprotection of EA pretreatment. When propranolol was given before each EA pretreatment in the EAP group, the cardioprotective effect of EA pretreatment was abolished, showing an involvement of beta-adrenoceptors in mediating the effect of EA pretreatment. There was no significant cardioprotective effect observed in the EAN group. The results suggest that pretreatment may be a better way to apply acupuncture in the prevention and treatment of coronary heart disease.

A preliminary study on the cardioprotection of acupuncture pretreatment in rats with ischemia and reperfusion: involvement of cardiac beta-adrenoceptors.

Our previous study showed that a cardioprotective effect was produced by pretreatment with acupuncture at bilateral Neiguan acupoints (PC6) and the effect of EA was diminished by propranolol, a nonspecific antagonist of beta-adrenoceptors (beta-ARs) which are the most powerful cardiac receptors, indicating an involvement of beta-ARs. The present study explored further the signaling mechanism underlying the cardioprotective effect of acupuncture pretreatment in rats subjected to myocardial ischemia and reperfusion (MIR). Myocardial ischemia was achieved by ligating the left anterior descending coronary artery and reperfusion by releasing the ligation. Adult rats were divided into three groups, namely, a normal control (NC) group, a group subjected to ischemia and reperfusion (IR) only, and a group given electro-acupuncture (EA) before IR. For EA, bilateral Neiguan points (PC6) of the rats were stimulated for 30 min once a day for 3 consecutive days. The ST segment of ECG, the ratio of infarct size over risk zone, and the contents of beta(1)-adrenoceptor (beta(1)-AR), Gsalpha protein and cAMP in ischemic myocardium were compared among the three groups. IR increased the elevation of ECG ST segment, myocardial infarct size, contents of beta(1)-AR, Gsalpha protein and cAMP. These effects were attenuated by EA pretreatment at bilateral Neiguan acupoints. In conclusion, the present results indicate that EA produces cardioprotective effect against IR which may be mediated via the beta(1)-AR-Gs-protein-cAMP pathway.

Acupuncture pretreatment protects heart from injury in rats with myocardial ischemia and reperfusion via inhibition of the beta(1)-adrenoceptor signaling pathway.

Our previous study showed that electro-acupuncture (EA) pretreatment protects the heart from injury of ischemia. The present study explored further whether adenylate cyclase (AC), protein kinase A (PKA), and L-type Ca(2+) channel, the beta(1)-AR signaling components modulating intracellular Ca(2+) ([Ca(2+)](i)), are involved in the mediation of the antiarrhythmic effect of EA pretreatment in the rats from which the hearts were subsequently isolated and subjected to simulative global ischemia and reperfusion (SGIR). SGIR was performed by perfusing the isolated heart at a low flow followed by normal perfusion. Adult rats were randomized into four groups, namely, normal control (NC), SGIR, EA, and NC plus EA (NCEA) groups. The rats in the EA and NCEA groups were given EA pretreatment at bilateral Neiguan points (PC6) for 30 min once a day in 3 consecutive days before the hearts were isolated and perfused. The arrhythmia score and the response of [Ca(2+)](i) to the activators of AC, PKA, and L-type Ca(2+) channel in single ventricular myocyte isolated from the hearts subjected to SGIR were compared among the groups. The results showed that the arrhythmia score was significantly higher in the SGIR group as compared with the NC and NCEA groups. The SGIR-enhanced arrhythmia score was significantly attenuated in the EA group. More interesting, EA pretreatment also attenuated the SGIR-enhanced response of [Ca(2+)](i) to the activators of AC, PKA, and the L-type Ca(2+) channel in the myocytes isolated from the hearts subjected to SGIR. In conclusion, EA pretreatment can produce an antiarrhythmic effect in the rat of SGIR. AC, PKA and the L-type Ca(2+) channel are involved in the mediation of the antiarrhythmic effect of EA pretreatment.

Antiarrhythmic effect of acupuncture pretreatment in rats subjected to simulative global ischemia and reperfusion--involvement of adenylate cyclase, protein kinase A, and L-type Ca2+ channel.

To discuss the potential role of medicinal herbs, especially those with effect of strengthening Qi, in the treatment of chronic heart failure (CHF) via modulating myocardial substrate metabolism. The relationships among heart failure, myocardial energetic metabolism and herbal medicine were analyzed in detail through reviewing and summarizing the accumulating knowledge and recent findings on myocardial metabolism, heart failure and herbal medicine. Either energy lack or abnormal energetic metabolism is one of the main causes to the initiation and development of heart failure. Recent studies suggest that the cardiac function in the patients with CHF could be improved by inhibiting the energy production from metabolism of fatty acid and enhancing the energy production from glucose metabolism. The concept of Qi in Chinese medicine is very close to the energy in western medicine. The decoction of Chinese medicine containing herbal medicine with effect of strengthening Qi and the herbal medicine themselves and their components were evidenced to be effective in improvement of heart failure and regulation of both lipid and glucose metabolism; more importantly, all these herbal medicine contain the multi-sugar which can be metabolized into single unit of sugar which may be metabolized as a substrate by myocardium and potentially produce the cardioprotective effect. Therefore, we may find out a novel way to explain why the herbal medicine with effect of strengthening Qi can improve cardiac function in patients with CHF. In other words, regulating myocardial metabolism is one of the mechanisms underlying the cardioprotection produced by herbal medicine with effect of strengthening Qi in the treatment of heart failure.

[New idea of treatment of heart failure with traditional Chinese medical].

Bone marrow stem cells (BMSCs) have the capacity to differentiate into mature cell types of multiple tissues. Thus, they represent an alternative source for organ-specific cell replacement therapy in degenerative diseases. In this study, we demonstrated that female rat BMSCs could differentiate into steroidogenic cells with the capacity for de novo synthesis of Estradiol-17 β (E2) under high glucose culture conditions with or without retinoic acid (RA). The cultured BMSCs could express the mRNA and protein for P450arom, the enzyme responsible for estrogen biosynthesis. Moreover, radioimmunoassay revealed that BMSCs cultured in the present culture system produced and secreted significant amounts of testosterone, androstenedione, and E2. In addition, RA promoted E2 secretion but did not affect the levels of androgen. These results indicate that BMSCs can synthesize and release E2 and may contribute to autologous transplantation therapy for estrogen deficiency.

Estradiol synthesis and release in cultured female rat bone marrow stem cells.

The previous study showed that the cardiac arrhythmias induced by myocardial ischemia and reperfusion were attenuated by the pretreatment of acupuncture; however, the related mechanism is not understood. The present study was therefore designed to determine whether intracellular Ca(2+) ([Ca(2+)]i) and connexin 43 (Cx43) are involved in the mediation of the anti-arrhythmic effect of electro-acupuncture (EA) pretreatment in the rats subjected to simulative global ischemia and reperfusion (SGIR).

Anti-arrhythmic effect of acupuncture pretreatment in the rats subjected to simulative global ischemia and reperfusion--involvement of intracellular Ca2+ and connexin 43.

To examine the effect of electroacupuncture (EA) treatment on abnormal defaecation in a rat model of chronic heterotypic stress (CHS) and investigate the underlying mechanisms.

Electroacupuncture ameliorates abnormal defaecation and regulates corticotrophin-releasing factor in a rat model of stress.

The specificity of acupoint effect is an important part of acupuncture theory. It has been one of the foci in acupuncture research domestically and abroad. This paper explores the specific relationship between Zusanli (ST 36) and stomach-intestine function based on the ancient records on " acupoint for  diseases" and the clinical and experimental researches on Zusanli(ST 36) treating digestive diseases. The physiological mechanism of the specificity is explained in terms of the spinal cord segment of Zusanli (ST 36) and gastrointestinal organs as well as the cerebral central effect of puncturing the acupoint. The aim of the paper is to provide more evidences for the specificity of acupoint effect indicated by " acupoint for  diseases".

[Discussion on specificity of acupoint effect based on " acupoint for  diseases"].

By reviewing the literature regarding the development mechanism of myocardial stunning, effects of acupuncture on myocardial ischemic injury, and correlation between acupuncture and κ-opioid receptor, it was suggested that acupuncture was highly likely to act on κ-opioid receptor in myocardial cells, and directly treated myocardial malfunction induced by myocardial stunning through κ-opioid receptor and its signaling pathway. In addition, acupuncture could inhabit the signaling pathway of adrenoceptor β1, one of the main functional receptors, to indirectly improve myocardial ischemic injury. From κ-opioid receptor signaling pathway, the action mechanism of acupuncture for prevention and treatment of myocardial stunning was discussed in this paper, hoping to provide new ideas for possible mechanism of acupuncture for myocardial ischemic injury.

[New thoughts in mechanism research of acupuncture for myocardial stunning from κ-opioid receptor signaling pathway].

To investigate the effects on the brain using three needling manipulations (twirling, lifting-thrusting, and twirling plus lifting-thrusting) when the right-side Zusanli (ST 36) acupoint was stimulated with needles.

Junhong Gao

Institute of Acupuncture and Moxibustion

China Academy of Chinese Medical Sciences

Visualizing the Morphological Characteristics of Neuromuscular Junction in Rat Medial Gastrocnemius Muscle

Junhong Gao

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Institute of Acupuncture and Moxibustion

China Academy of Chinese Medical Sciences

Visualizing the Morphological Characteristics of Neuromuscular Junction in Rat Medial Gastrocnemius Muscle

Institute of Acupuncture and Moxibustion