EFFECTS OF ACUPUNCTURE ON nNOS AND iNOS EXPRESSION IN THE ROSTRAL VENTROLATERAL MEDULLA OF STRESS-INDUCED HYPERTENSIVE RATS

Adenosine A2A receptors in the rostral ventrolateral medulla participate in blood pressure decrease with electroacupuncture in hypertensive rats

Acupuncture is increasingly used to manage high blood pressure (BP) as a complementary therapy. However, the mechanisms underlying its hypotensive effects remain unclear. Our previous studies have shown that electroacupuncture (EA) at the ST36-37 acupoints, overlying the deep peroneal nerve, attenuates pressor responses through adenosine A2A receptors (A2AR) in the rostral ventrolateral medulla (rVLM). However, it is uncertain whether rVLM A2AR contributes to EA's BP-lowering effect in sustained hypertension. We hypothesized that a course of EA treatment lowers BP, in part, through the activation of adenosine A2AR in the rVLM in hypertensive rats. To mimic essential hypertension in the clinic, we performed EA in conscious Dahl salt-sensitive hypertensive rats (DSHRs). EA (0.1-0.4 mA, 2 Hz) was applied at ST36-37 for 30 min twice weekly for four weeks, while sham-EA was conducted in a similar manner but without electrical input. In hypertensive rats, BP was reduced by EA (n = 14) but neither by sham-EA (n = 14) nor in the absence of needling (n = 8). Following four weeks of eight treatments and then under anesthesia, EA's modulatory effect on elevated BP was reversed by unilateral rVLM microinjection of SCH 58261 (1 mM in 50 nl; an A2AR antagonist; n = 7; P < 0.05) but not the vehicle (n = 5) in EA-treated DSHRs. Activation of rVLM A2AR in DSHRs treated with sham-EA by an A2AR agonist, CGS-21680 (0.4 mM in 50 nl; n = 8), decreased BP. Unilateral administration of SCH 58261 or CGS-21680 into the rVLM did not alter basal BP in Dahl salt-sensitive rats fed a regular diet with normal BP. The A2AR level in the rVLM after EA was increased compared to the sham-EA and untreated DSHRs (n = 5 in each group; all P < 0.05). These data suggest that a 4-week twice weekly EA treatment reduced BP in salt-sensitive hypertensive rats likely through adenosine-mediated A2AR in the rVLM.

Effect of Acupuncture at LR3 on Cerebral Glucose Metabolism in a Rat Model of Hypertension: A 18F-FDG-PET Study

Our objective was to investigate the effect of acupuncture at LR3 on cerebral glucose metabolism in spontaneously hypertensive rats (SHRs). We used ¹⁸F-2-fluoro-deoxy-D-glucose positron emission tomography (¹⁸F-FDG-PET) to examine the effects of acupuncture at LR3 on cerebral glucose metabolism in SHRs. SHRs were randomly allocated to receive no treatment (SHR group), needling at LR3 (SHR + LR3 group), or sham needling (SHR + sham group). Rats received 10 min acupuncture once per day for 7 days and were compared to normotensive Wistar Kyoto (WKY) rats. Blood pressure (BP) measurement and PET were performed after the first needling and the 7-day treatment period. BP was lower in the SHR + LR3 group compared to the other SHR groups between 30 and 60 min after the first needling and at 24 and 48 h after the 7-day treatment period. Glucose metabolism in the motor, sensory, and visual cortices was decreased in SHR group compared to WKY group. Needling at LR3 was associated with decreased glucose metabolism in the dorsal thalamus, thalamus, and hypothalamus and with increased metabolism in the cerebellar anterior and posterior lobes, medulla oblongata, and sensory cortex compared to the SHR group. These findings suggest that LR3 acupuncture improves hypertension through a mechanism involving altered brain activation in SHRs.

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.

Abdominal and auricular acupuncture reduces blood pressure in hypertensive patients

INTRODUCTION

Hypertension is an important risk factor of cardiovascular disease (CVD), which is associated with premature death, myocardial infarction, stroke, peripheral vascular disease, and renal disease. The goal of the present study was to use a randomized controlled clinical trial to explore and compare the effectiveness of abdominal and auricular acupuncture on blood pressure in 440 subjects with and without obesity.

METHODS

Four hundred participants were recruited and randomized to one of four groups: cases and controls receiving auricular acupuncture (204 subjects) and cases and controls receiving abdominal electroacupuncture (196 subjects). Blood pressure and anthropometric parameters were measured before and after the intervention period. In order to match the initial diet of the groups, participants were required to follow an isocaloric diet for two weeks before the trial, and a low-calorie diet for 6 weeks during the intervention period.

RESULTS

We observed a significant time dependent improvement in the systolic blood pressure measurements in the abdominal intervention group, although this improvement was more pronounce in the first period of study. Of note, in the auricular intervention group, a significant increasing in the level of SBP was detected. Importantly no statistically significant changes were found in the corresponding sham groups.

CONCLUSIONS

Our findings demonstrated that abdominal electro-acupuncture for 6 weeks reduced both systolic and diastolic blood pressure and auricular acupuncture had a short-term adverse effect on both SBP and DBP.

The ameliorating effects of long-term electroacupuncture on cardiovascular remodeling in spontaneously hypertensive rats

Background

The purpose of this study was to investigate the inhibitory effects of long-term electroacupuncture at BaiHui (DU20) and ZuSanLi (ST36) on cardiovascular remodeling in spontaneously hypertensive rats (SHR) and underlying mechanisms.

Methods

6-weeks-old SHR or Wistar male rats were randomly, divided into 6 groups: the control group (SHR/Wistar), the non-acupoint electroacupuncture stimulation group (SHR-NAP/Wistar-NAP) and the electroacupuncture stimulation at DU20 and ST36 group (SHR-AP/Wistar-AP), 24 rats in each group. Rats were treated with or without electroacupuncture at DU20 and ST36, once every other day for a period of 8 weeks. The mean arterial pressure (MAP) was measured once every 2 weeks. By the end of the 8th week, the left ventricular structure and function were assessed by echocardiography. The content of angiotensin II (Ang II), endothelin-1 (ET-1) and nitric oxide (NO) in the plasma was determined using enzyme-linked immunosorbent assay. Histological studies on the heart and the ascending aorta were performed. The expression of angiotensin II type 1 receptor (AT1R), endothelin-1 type A receptor (ETAR), eNOS and iNOS in rat myocardium and ascending aorta was investigated by Western blotting.

Results

The MAP in SHR increased linearly over the observation period and significantly reduced following electroacupuncture as compared with sham control SHR rats, while no difference in MAP was observed in Wistar rats between electroacupuncture and sham control. The aortic wall thickness, cardiac hypertrophy and increased collagen level in SHR were attenuated by long term electroacupuncture. The content of Ang II, ET-1 in the plasma decreased, but the content of NO increased after electroacupuncture stimulation in SHR. Long term electroacupuncture significantly inhibited the expression of AT1R, ETAR and iNOS, whereas increased eNOS expression, in myocardium and ascending aorta of SHR.

Conclusions

The long term electroacupuncture stimulation at DU20 and ST36 relieves the increased MAP and cardiovascular abnormality in both structure and function in SHR, this beneficial action is most likely mediated via modulation of AT1R-AT1R-ET-1-ETAR and NOS/NO pathway.

The effects of acupuncture on the levels of blood pressure and nitric oxide in hypertensive patients

Hypertension possess a significant risk factor for a variety of diseases and affects millions of people all around the world. Recent studies suggest that NO plays a role in pathogenesis of hypertension while some investigators find a close relationship between acupuncture treatment and NO levels. We therefore aimed to investigate the effect of acupuncture on the levels of blood pressure and nitric oxide (NO) in hypertensive patients. After obtaining institutional ethics committee approval and patients' informed consent, 32 essential hypertensive patients aged between 32-65 and taking antihypertensive drugs were included to the study. A total of 10 sessions of manual acupuncture were applied on body acupoints (EX-HN3 (Yintang), KI 3, LIV 3, SP 9, LI 4, HT 7, ST 36, SP 6) in 10 weeks. Systolic (SBP) and diastolic blood pressure (DBP) levels and blood NO levels were measured for 3 times (i.e. before & after the first session, and after the 10th session). Main outcome measures of our study were the changes in SBP and DBP as well as nitric oxide levels between 3 measurements were compared. Our study showed that SBP and DBP values decreased both after the 1st and 10th sessions of acupuncture treatments (p<0.05). The NO concentration also increased both after the 1st (71.5%) and 10th sessions (184.6%) (p<0.05).

Orexin A regulates cardiovascular responses in stress-induced hypertensive rats

Several pieces of evidence indicate that the rostral ventrolateral medulla (RVLM) is probably one of the key neural structures mediating the pressor effects of orexins in the brain. Nitric oxide synthase/nitric oxide (NOS/NO) system in the RVLM modulates cardiovascular activities. Our experiments were designed to test the hypothesis that orexin-A (OXA) is involved in the mechanism of stress-induced hypertension (SIH) by adjusting NOS/NO system in the RVLM. The stress-induced hypertensive rats (SIHR) model was established by electric foot-shocks and noises. Here we examined the expression of OXA immunoreactive (OXA-IR) cells in the lateral hypothalamus (LH) and the protein level of orexin 1 receptor (OX1R) in the RVLM of SIHR, and we found that the expressions of OXA-IR and OX1R were higher than those of the control group. The double-staining immunohistochemical evidence showed that OX1R immunoreactive (OX1R-IR) cells and neuronal nitric oxide synthase (nNOS) or inducible nitric oxide synthase (iNOS) immunoreactive (IR) cells were co-localizated in the RVLM. Microinjection of OXA (10, 50, 100 pmol/100 nl) into the unilateral (right) RVLM of control rats or SIHR produced pressor and tachycardiac effects in a dose-dependent manner. SB-408124 (100 pmol/100 nl, an antagonist of OX1R) or TCS OX2 29 (100 pmol/100 nl, an antagonist of OX2R) partly abolished the cardiovascular effects of exogenously-administrated OXA into the RVLM of control rats and SIHR, and lowered the increased systolic blood pressure (SBP) and heart rate (HR) of SIHR, with no difference in statistical significance between the two antagonists' effects. Microinjection into the RVLM of both control and SIHR groups of 7-Ni (0.05 pmol/100 nl, nNOS inhibitor) or Methylene Blue [100 pmol/100 nl, an inhibitor of soluble guanylate cyclase (sGC)] suppressed the OXA-induced increase of SBP and HR, whereas microinjection of AG (1, 10, 100 pmol/100 nl) had no obvious effects on the OXA-induced increase of SBP and HR. Our results indicate that OXA in the RVLM may participate in the central regulation of cardiovascular activities in SIHR, and OX1R and OX2R both have important roles in it. The cardiovascular effects of OXA in the RVLM may be induced by nNOS-derived NO, which activated sGC-associated signaling pathway.

Proteomic response to acupuncture treatment in spontaneously hypertensive rats

Previous animal and clinical studies have shown that acupuncture is an effective alternative treatment in the management of hypertension, but the mechanism is unclear. This study investigated the proteomic response in the nervous system to treatment at the Taichong (LR3) acupoint in spontaneously hypertensive rats (SHRs). Unanesthetized rats were subject to 5-min daily acupuncture treatment for 7 days. Blood pressure was monitored over 7 days. After euthanasia on the 7^th day, rat medullas were dissected, homogenized, and subject to 2D gel electrophoresis and MALDI-TOF analysis. The results indicate that blood pressure stabilized after the 5th day of acupuncture, and compared with non-acupoint treatment, Taichong-acupunctured rat’s systolic pressure was reduced significantly (P<0.01), though not enough to bring blood pressure down to normal levels. The different treatment groups also showed differential protein expression: the 2D images revealed 571±15 proteins in normal SD rats’ medulla, 576±31 proteins in SHR’s medulla, 597±44 proteins in medulla of SHR after acupuncturing Taichong, and 616±18 proteins in medulla of SHR after acupuncturing non-acupoint. In the medulla of Taichong group, compared with non-acupoint group, seven proteins were down-regulated: heat shock protein-90, synapsin-1, pyruvate kinase isozyme, NAD-dependent deacetylase sirtuin-2, protein kinase C inhibitor protein 1, ubiquitin hydrolase isozyme L1, and myelin basic protein. Six proteins were up-regulated: glutamate dehydrogenase 1, aldehyde dehydrogenase 2, glutathione S-transferase M5, Rho GDP dissociation inhibitor 1, DJ-1 protein and superoxide dismutase. The altered expression of several proteins by acupuncture has been confirmed by ELISA, Western blot and qRT-PCR assays. The results indicate an increase in antioxidant enzymes in the medulla of the SHRs subject to acupuncture, which may provide partial explanation for the antihypertensive effect of acupuncture. Further studies are warranted to investigate the role of oxidative stress modulation by acupuncture in the treatment of hypertension.

Electroacupuncture and moxibustion decrease renal sympathetic nerve activity and retard progression of renal disease in rats

BACKGROUND/AIM

Chronic kidney disease (CKD) is an increasing major public health problem worldwide. The sympathetic nervous system and nitric oxide play an important role in the pathogenesis of CKD. Traditional Chinese medicine has accumulated thousands of years of therapeutic experiences. Electroacupuncture (EA) and moxibustion (MO) are two such therapeutic strategies. The aim of this study was to investigate the renal and hemodynamic effects of EA-MO in an experimental model of a CKD.

METHODS

Male Wistar rats submitted to 5/6th nephrectomy (5/6 NX) were studied for 8 weeks. There were four groups: (1) control, normal rats; (2) NX, 5/6 NX only; (3) NX-AS, 5/6 NX and EA-MO session using sham points, and (4) NX-AM, 5/6 NX and EA-MO session using real acupoints. Biochemical and blood pressure studies, renal sympathetic nerve activity measurements, nitric oxide levels and the histopathological indices were assessed.

RESULTS

The EA- and MO-treated group presented significant improvement in all measured functional and histopathological parameters.

CONCLUSION

These findings suggest that EA-MO had beneficial effects on CKD. This effect was probably achieved by the modulation of the renal sympathetic nerve activity and nitric oxide levels, leading to decreased blood pressure, which is associated with less proteinuria.

Regulation of the cardiovascular function by CO2 laser stimulation in anesthetized rats

Physical stimulation of body surface points is known to affect various organ functions. In traditional Chinese medicine, so-called acupoints were defined. These points can be physically stimulated to effectively treat various diseases. Here we describe for the first time the effect of CO(2) laser stimulation at the acupoints Neiguan (PC-6), Quchi (LI-11), Zusanli (ST-36), and Taichong (LR-3) on heart rate and mean arterial blood pressure in anesthetized rats. CO(2) laser stimulation increased the skin surface temperature to 54°C. Our results revealed that the laser stimulation at the left or right PC-6 and LR-3 increased heart rate and mean arterial pressure. There was no response of heart rate and mean arterial pressure during and after stimulation of the left LI-11, but laser stimulation at the right LI-11 slightly increased heart rate and mean arterial pressure. On the other hand, laser stimulation at the left and right ST-36 decreased heart rate and mean arterial pressure. The effects on mean arterial pressure were more pronounced than those on heart rate. After full spinal cord transection, all heart-rate and mean-arterial-pressure responses were attenuated or completely abolished. These results suggest that CO(2) laser stimulation at either the left or right PC-6, ST-36, and LR-3, as well as at the right LI-11 can modulate the cardiovascular functions in anesthetized rats, and its modulatory site might be supraspinal.

Pulse width modulation electro-acupuncture on cardiovascular remodeling and plasma nitric oxide in spontaneously hypertensive rats

This study was designed to investigate the effect of pulse width modulation electro-acupuncture (PWM-EA) on cardiovascular remodeling and nitric oxide (NO) in spontaneously hypertensive rats (SHR). Thirty-four male SHR were randomly divided into control, captopril, and two PWM-EA groups, which were treated with 350 Hz (SHR-350 Hz) and whole audio bandwith electro-acupuncture (SHR-WAB group) respectively, on the ST 36 point located on the outside of the hind leg. Systolic blood pressure (BP), plasma and myocardial NO were measured. Histological studies were also performed on the aortic wall and the left ventricle. The BP in the SHR-350 Hz, SHR-WAB and the captopril groups was lower than in the control group following the treatment (P < .05). The average aortic media wall thickness in the two electro-acupuncture groups was less than in the control group (P < .05). The left ventricle/heart weight ratio in the captopril and SHR-350 Hz groups was less than in the control group (P < .01), but was similar between the SHR-WAB and the control group (P > .05). The plasma and myocardium NO levels were elevated in the captopril and the SHR-350 Hz group (P < .05 and .01, resp.). The plasma level of NO in the SHR-WAB group was also higher than in the control group (P < .05). We concluded that pulse width modulation electro-acupuncture on the ST 36 point prevents the progression of hypertension and diminishes the cardiovascular remodeling in SHR. It also elevates plasma and cardiac NO in this animal model.

Electroacupuncture Delays Hypertension Development through Enhancing NO/NOS Activity in Spontaneously Hypertensive Rats

Using spontaneously hypertensive rats (SHR), this study investigated whether electroacupuncture (EA) could reduce early stage hypertension by examining nitric oxide (NO) levels in plasma and nitric oxide synthase (NOS) levels in the mesenteric resistance artery. EA was applied to the acupuncture point Governor Vessel 20 (GV20) or to a non-acupuncture point in the tail twice weekly for 3 weeks under anesthesia. In conscious SHR and normotensive Wistar Kyoto (WKY) rats, blood pressure was determined the day after EA treatment by the tail-cuff method. We measured plasma NO concentration, and evaluated endothelial NO syntheses (eNOS) and neuronal NOS (nNOS) protein expression in the mesenteric artery. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower after 3 weeks of GV20 treatment than EA at non-acupuncture point and no treatment control in SHR. nNOS expression by EA was significantly different between both WKY and no treatment SHR control, and EA at GV20 in SHR. eNOS expression was significantly high in EA at GV 20 compared with no treatment control. In conclusion, EA could attenuate the blood pressure elevation of SHR, along with enhancing NO/NOS activity in the mesenteric artery in SHR.

Effects of electro-acupuncture on endothelium-derived endothelin-1 and endothelial nitric oxide synthase of rats with hypoxia-induced pulmonary hypertension

Pulmonary hypertension (PH) is characterized by elevated pulmonary artery pressure (PAP), pulmonary vascular remodeling and right ventricular hypertrophy, which are mainly due to endothelial dysfunction. Electro-acupuncture has shown beneficial effects on cardiovascular homeostasis, but little evidence has been obtained on pulmonary effects. The goal of the present study was to investigate whether electro-acupuncture on bladder-13 and -15 points can protect against chronic hypoxia-induced PH by regulating endothelium-derived endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS). Male Wistar rats were exposed to hypoxia to induce PH. Hemodynamic analysis revealed that mean PAP was similar under normoxic conditions. Chronic hypoxia increased mean PAP to 37 ± 3 mmHg, and electro-acupuncture attenuated it to 29 ± 3 mmHg. Absolute right ventricular weight was ameliorated by electro-acupuncture from 0.288 ± 0.048 g to 0.228 ± 0.029 g under hypoxic conditions. Hypoxia-induced right ventricular hypertrophy index decreased from 0.477 ± 0.069 to 0.378 ± 0.053 with electro-acupuncture treatment. Histological examination revealed that hypoxic rats showed increased medial pulmonary artery wall thickness as well as muscularization. However, these alternations by chronic hypoxia were attenuated by electro-acupuncture. There was no difference in eNOS or ET-1 between groups under normoxic conditions. Electro-acupuncture treatment significantly improved the circulating eNOS concentration (365.36 ± 31.51 pg/mL) compared with only hypoxia exposure (247.60 ± 30.64 pg/mL). In lung homogenate, levels of eNOS under hypoxia increased from 684.96 ± 117.90 to 869.86 ± 197.61 pg/mg by electro-acupuncture treatment. Levels of ET-1 changed oppositely to eNOS in response to electro-acupuncture (ET-1 in plasma, 29.44 ± 2.09 versus 20.70 ± 2.37 pg/mL; ET-1 in lung homogenate, 120.51 ± 3.03 versus 110.60 ± 4.04 pg/mg). In conclusion, these results indicated that treatment with electro-acupuncture can protect against hypoxia-induced PH, possibly by regulating the balance of endothelium-derived vasoconstrictors and vasodilators.

Control of systemic and pulmonary blood pressure by nitric oxide formed through neuronal nitric oxide synthase

Nitric oxide formed by neuronal nitric oxide synthase (nNOS) in the brain, autonomic inhibitory (nitrergic) nerves, and heart plays important roles in the control of blood pressure. Activation of nitrergic nerves innervating the systemic vasculature elicits vasodilatation, decreases peripheral resistance, and lowers blood pressure. Impairment of nitrergic nerve function, as well as endothelial dysfunction, results in systemic and pulmonary hypertension and decreased regional blood flow. Blockade of nNOS activity in the brain, particularly the medulla and hypothalamus, causes systemic hypertension. Under hypertensive states, such as those in spontaneously hypertensive and Dahl salt-sensitive rats, the expression of the nNOS gene in the brain is increased; this appears to counteract the activated sympathetic function in the vasomotor center. The present article summarizes information concerning the modulation of systemic and pulmonary hypertension through nNOS-derived nitric oxide produced in the brain and periphery.

Effects of electrical stimulation of acupuncture points on blood pressure

OBJECTIVE

Arterial hypertension is considered a major contributor to coronary arterial disease. The purpose of the study was to investigate the effects of Hans electrical stimulation of acupuncture points on blood pressure.

METHODS

Subjects with normal and elevated blood pressure were recruited and randomly assigned into control and experimental groups. Only the experimental subjects received active Hans electrical stimulation on 2 acupuncture points for 30 minutes each session, twice a week for 5 weeks.

RESULTS

Twenty-seven subjects (17 male) were recruited and completed the study. The average age of the subjects was 25 +/- 5 years. The youngest subject was 20 years old and the oldest was 36 years old. After using the Hans electrical stimulation on acupuncture points for 5 weeks, the systolic blood pressure decreased significantly in the experimental group with active treatment. The mean systolic blood pressure was 117.8 +/- 4.2 mm Hg before the treatment and was reduced to 110.8 +/- 5.5 mm Hg (P < .05) in the third week and to 110.1 +/- 5.8 mm Hg in the fifth week (P < .05). The mean diastolic blood pressure was 78.1 +/- 5.0 mm Hg before treatment and was reduced to 77.4 +/- 4.3 mm Hg (P > .05) in the third week and to 74.8 +/- 4.3 mm Hg (P > .05) in the fifth week, but both did not reach statistically significant levels. The systolic and diastolic blood pressures in the control group did not show statistically significant changes. The mean systolic blood pressure was 115.6 +/- 13.3 mm Hg before the treatment and was reduced to 113.0 +/- 12.6 mm Hg (P > 0.05) in the third week and to 112.2 +/- 10.3 mm Hg in the fifth week (P > .05). The mean diastolic blood pressure was 76.4 +/- 7.9 mm Hg before treatment and was reduced to 76.5 +/- 6.9 mm Hg (P > .05) in the third week and to 73.9 +/- 5.4 mm Hg (P > .05) in the fifth week.

CONCLUSION

It was concluded that Hans electrical stimulation of acupuncture points reduced systolic blood pressure but not the diastolic blood pressure in the current subject population with normal and elevated blood pressure.

Electroacupuncture decreases nitric oxide synthesis in the hypothalamus of spontaneously hypertensive rats

Acupuncture-related effects on autonomic function have been explored via biological and neurophysiologic studies. The hypothalamus, known to regulate the autonomic nervous system, is likely affected by acupuncture treatment that modulates sympathetic functions. The aim of this study was to investigate the effect of electroacupuncture at the Jogsamni point (ST36, an acupoint known to modulate autonomic function) on expression of neuronal nitric oxide synthase (nNOS) in the hypothalamus of spontaneously hypertensive rat. Nitric oxide, which is produced by nNOS activity, plays an important role in the regulation of many physiologic processes, including sympathetic activities, in the hypothalamus and other parts of the brain. nNOS expression was assessed by immunohistochemistry of nNOS and histochemistry of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d). The staining intensities of nNOS-positive neurons and NADPH-d-positive neurons were quantitatively assessed using microdensitometry to measure changes in optical density. The results show that electroacupuncture at ST36 reduced the expression and activity of nNOS in the hypothalamus of spontaneously hypertensitive rats. These findings suggest that the electroacupuncture at ST36 results in modulation of the activity of nNOS in the hypothalamus of spontaneously hypertensive rat.