The protective effects of electro-acupuncture in thoracic surgery on trauma stressed rats involve the rostral ventrolateral medulla and supraoptic nucleus.

The present study was designed to explore whether the rostral ventrolateral medulla (RVLM) and supraoptic nucleus (SON) were involved in the protective effects of electro-acupuncture (EA) in thoracic surgery on trauma-stressed rats. The rats were randomly divided into a non-stressed group (Control), surgical trauma-stressed group (Trauma), and Neiguan EA applied on the surgical trauma-stressed group (Trauma+EA-PC 6). RVLM neuron discharge was observed by using an in vivo electrophysiological method, and micro-dialysis combining high-performance liquid chromatography with fluorometric detection (HPLC-FD) was used to assess expression of amino acids in the RVLM. Immunohistochemical methods were used to assess c-Fos expression in SON neurons. The trauma of surgical stress was shown to dramatically increase the discharge frequency of RVLM neurons and promote the release of glutamate and taurine in the RVLM. The expression of c-Fos was also significantly increased in the SON of traumatized rats. EA application at Neiguan acupoints significantly suppressed trauma-induced increase of discharge frequency of the RVLM neurons, almost completely suppressed the trauma-induced increase of glutamate release but only very slightly reduced the trauma-enhanced taurine release, and inhibited the increase of c-Fos expression in these SON neurons of traumatized rats. These results indicate that Neiguan EA may improve cardiac function by modulating neurons in the RVLM and the SON in surgically traumatized rats. The taurine-mediated negative feedback may be involved in the protective effect of EA on cardiac function.

Repeated electroacupuncture attenuating of apelin expression and function in the rostral ventrolateral medulla in stress-induced hypertensive rats.

Studies have revealed that apelin is a novel multifunctional peptide implicated both in blood pressure (BP) regulation and cardiac function control. Evidence shows that apelin and its receptor (APJ) in the rostral ventrolateral medulla (RVLM) may play an important role in central BP regulation; however, its role is controversial and very few reports have shown the relationship between acupuncture and apelin. Our study aims to both investigate the apelinergic system role in stress-induced hypertension (SIH) and determine whether acupuncture therapy effects on hypertension involve the apelinergic system in the RVLM. We established the stress-induced hypertensive rat (SIHR) model using electric foot-shock stressors with noise interventions. The expression of both apelin and the APJ receptor in the RVLM neurons was examined by immunohistochemical staining and Western blots. The results showed apelin expression increased remarkably in SIHR while APJ receptor expression showed no significant difference between control and SIHR groups. Microinjection of apelin-13 into the RVLM of control rats or SIHR produced pressor and tachycardic effects. Furthermore, effects induced by apelin-13 in SIHR were significantly greater than those of control rats. In addition, repetitive electroacupuncture (EA) stimulation at the Zusanli (ST-36) acupoint attenuated hypertension and apelin expression in the RVLM in SIHR; it also attenuated the pressor effect elicited by exogenous apelin-13 microinjection in SIHR. The results suggest that augmented apelin in the RVLM was part of the manifestations of SIH; the antihypertensive effects of EA might be associated with the attenuation of apelin expression and function in the RVLM, which might be a novel role for EA in SIH setting.

Protective effects of electroacupuncture on cardiac function in rats subjected to thoracic surgery trauma.

The present study investigates the protective effects of electroacupuncture (EA) application on cardiac function, while simultaneously exploring the underlying neurobiological mechanisms, in rats that have experienced thoracic surgery-induced stress. Mean arterial and left intraventricular pressures were monitored as indicators of cardiac function. Meanwhile, the immunohistochemistry for c-Fos protein expression and electrophysiology in vitro in brain nuclei, known to regulate cardiac function, provide insights into the effects of EA on the central nervous system. The results show that cardiac function was dramatically suppressed with thoracic surgery trauma, the expression levels of c-Fos in the paraventricular nucleus (PVN) and the rostral ventrolateral medulla (RVLM) significantly increased, the rheobase intensity of the intracellular current injection needed to initiate the action potential decreased, membrane resistance in the PVN neurons significantly increased, and the inductivity of the postsynaptic potentials in the PVN neurons of the surgery-treated rats significantly decreased. EA application at the Neiguan acupoints (PC6) attenuated the decreases in almost all investigated functional parameters of the heart. EA significantly decreased the number of Fos-immunoreactive neurons in the PVN and RVLM, significantly decreased the Max L. slope of the PVN neurons, and increased the inductivity of the postsynaptic potentials in the PVN neurons of the surgery-treated rats. These data indicate the protective effects of EA application on cardiac function in rats that have experienced surgery-induced stress and show that EA application at the Neiguan acupoints may produce its protective effects through the neurons in the PVN and the RVLM.

Differential expressions of nNOS and iNOS in the rostral ventrolateral medulla induced by electroacupuncture in acute myocardial ischemia rats.

Increasing lines of evidence has been accumulated that nitric oxide (NO) and nitric oxide synthase (NOS) distribute plentifully in the rostral ventrolateral medulla (RVLM) and contribute to cardiovascular regulation. In the present study, the expressions of neuronal and inducible isoform of NOS (nNOS and iNOS) were observed in the RVLM of acute myocardial ischemia (AMI) Wistar rats experienced electroacupuncture (EA) treatment, thereby the cardiovascular effects of NO in the RVLM were investigated and the mechanism of acupuncture effect on AMI was inferred. The results indicated that in the AMI rats, cardiac functions were markedly attenuated with high serum level of brain natriuretic peptide (BNP) and norepinephine (NE), the number of nNOS-immunoreactive cells and nNOS mRNA exprossion in the RVLM area were increased, while those of iNOS were lowered. EA at "Neiguan" acupoints (Pe 6) 30 min daily for successive 5 d resulted in an improvement of the cardiac functions, decreases in NE and BNP levels; it also increased the expression of iNOS and decreased the expression of nNOS in the RVLM. These results suggest that the curative effect of acupuncture on AMI is possibly attributable to the differential regulation of NOS/NO in the RVLM, leading to decreased sympathetic outflow and improvement of cardiac functions.