Nitric oxide mediates cerulein-induced relaxation of canine sphincter of Oddi

Effect of acupuncture at Foot-Yangming Meridian on gastric mucosal blood flow, gastric motility and brain-gut peptide

AIM: To observe the effect of acupuncture at Foot-Yangming Meridian on gastric mucosal blood flow (GMBF), gastric motility and brain-gut peptide.

METHODS: Sixty SD rats were randomly divided into 6 groups: normal control group, model group (group with gastric mucosal damage, GMD), Sibai group (with acupuncture at Sibai point + GMD), Tianshu group (with acupuncture at Tianshu point + GMD), Zusanli group (with acupuncture at Zusanli point + GMD) and non-acupoint group (with acupuncture at non-acupoint + GMD). The GMD model group was induced by infusing pure alcohol into gastric cavity. H₂ Gas Clearance Test (HGCT) was used to measure GMBF, the frequency and amplitude of gastric motility were measured by the method of aerocyst, the content of brain-gut peptide in sinus ventriculi and bulbus medullae were detected by radioimmunoassay.

RESULTS: Inhibitory effect of the frequency and amplitude of gastric motility were shown in model group, and the rates of frequency and amplitude changes were remarkably different from the normal control group (-19.41 ± 17.21 vs -4.71 ± 10.32, P < 0.05; -51.61 ± 29.02 vs 1.81 ± 14.12, P < 0.01). In comparison with control group, the GMBF was 0.52 ± 0.161 mL vs 1.03 ± 0.255 mL per 100g tissue/min, P < 0.01, the content of motilin in sinus ventriculi and bulbus medullae was 63.04 ± 7.77 pg/mL vs 72.91 ± 8.42 pg/mL, P < 0.05 and 50.96 ± 8.77 pg/mL vs 60.76 ± 8.05 pg/mL, P < 0.05, but the content of somatostatin in sinus ventriculi and bulbus medullae was 179.85 ± 43.13 ng/g vs 90.54 ± 40.42 ng/g, P < 0.01 and 532.86 ± 122.58 ng/g vs 370.91 ± 76.29 ng/g, P < 0.05,respectively. In comparison with model group, the amplitude of gastric motility was 1.52 ± 20.13, -6.52 ± 23.31, 6.92 ± 25.21 vs -51.61 ± 29.02, P < 0.01 and GMBF was 0.694 ± 0.160 mL vs 0.893 ± 0.210 mL, 1.038 ± 0.301 mL vs 0.52 ± 0.161 mL per 100g tissue/min, P < 0.01, respectively in Tianshu, Sibai and Zusanli groups, the content of motilin in sinus ventriculi and bulbus medullae was 71.64 ± 9.35 pg/mL vs 63.04 ± 7.77 pg/mL, P < 0.05; 58.96 ± 6.69 pg/mL vs 50.96 ± 8.77 pg/mL, P < 0.05 in Zusanli group and 72.84 ± 8.62 pg/mL vs 63.04 ± 7.77 pg/mL, P < 0.05 in Sibai group, while the content of somatostatin in bulbus medullae in Tianshu, Sibai and Zusanli groups was 480.62 ± 151.69 ng/g, 388.53 ± 155.04 ng/g, 365.76 ± 143.93 ng/g vs 532.86 ± 122.58 ng/g, P < 0.05, respectively.

CONCLUSION: Electro-acupuncture at acupoints of Foot-Yangming Meridian could enhance the gastric motility, improve GMBF, and regulate the content of motilin and somatostatin in sinus ventriculi and bulbus. The effects of acupuncture on GMBF and gastric motility may be related to the content of brain-gut peptide.

Effects of electroacupuncturing at Zuyangming and Zushaoyang Jingxue on stomach and gallbladder kineses and related brain-gut peptide in rabbits

AIM: To investigate the correlation between the meridians and zang-fu as well as the specific effect of the points on their related zang-fu.

METHODS: Atropine was intravenously injected in the rabbits to inhibit the myoelectric activities of the stomach and the sphincter of oddi (SO). After electroacupuncturing at Zusanli and Yanglingquan points, the myoelectric activities of the stomach and SO were observed, and the levels of motilin (MTL) and cholcystokinin (CCK) in the antrum, SO and plasma were measured.

RESULTS: After atropine injection, the mean amplitudes for the high activity of myoelectric slow wave and fast wave were significantly decreased (P = 0.028, P = 0.001). Moreover, the average frequency of myoelectric slow wave was not significantly changed. The mean amplitudes for the myoelectric slow wave and fast wave were enhanced to some extent after electroacupuncturing at Zusanli and Yanglingquan points. The levels of MTL (P = 0.000) and CCK (P = 0.001) in the antrum, SO and plasma were increased markedly after electroacupuncturing at Zusanli and Yanglingquan points. The levels of MTL in the antrum (P = 0.020) and plasma (P = 0.001) and CCK in plasma (P = 0.001) were obviously increased after electroacupuncturing at Zusanli point, whereas the levels of MTL in SO and CCK in the antrum and SO were notably increased after electroacupuncturing at Yanglingquan point. There was a positive effect on the release of MTL and CCK after electroacupuncturing at the points.

CONCLUSION: The inhibition for the myoelectric activities of the stomach and SO are improved after electroacupuncturing at Zusanli and Yanglingquan points. The possible mechanism may be that the acupuncture influences the release of MTL and CCK, so as to regulate the activity of the alimentary canal.

The sphincter of Oddi: understanding its control and function

The most common functional disorders of the biliary tract and pancreas are associated with disordered motility of the sphincter of Oddi (SO). The SO is a neuromuscular structure located at the junction of the bile and pancreatic ducts with the duodenum. The primary functions of the SO are to regulate the delivery of bile and pancreatic juice into the duodenum, and to prevent the reflux of duodenal contents into the biliary and pancreatic systems. Disordered motility of the SO leads to the common and painful clinical conditions of SO dysfunction and acute pancreatitis. In order to understand normal SO motility, studies have been performed addressing SO function, control of spontaneous SO activity, responses to bioactive agents, SO innervation, and reflexes with other gastrointestinal organs. These studies have led to the current understanding of how the SO functions and may permit the development of targeted therapy for SO dysfunction and acute pancreatitis. This review summarizes the current knowledge regarding the control and regulation of SO motility, highlighting laboratory based and clinical research performed over the last 5 years.

Gastrointestinal smooth muscle cell as target for gene transfer of eNOS gene

AIM

To generate an adenoviral vector carrying endothelial nitric-oxide synthase (eNOS) gene in order to mediate the expression of eNOS gene in gastrointestinal smooth muscle cells (SMC) and assess the enzyme activity of eNOS.

METHODS

A recombinant adenovirus (Ad-eNOS) containing the bovine eNOS cDNA fragment was generated by homologous recombination in bacteria. The SMC of distal part of esophagus and gastric fundus of cat were isolated and cultured in vitro and infected with Ad-eNOS. The expression of eNOS gene was detected by Western blot and RT-PCR. The enzyme activity of NOS and the output of NO in SMC were measured by NOS and NO assay kit, furthermore, the different effects of given factors on the enzyme activity and the yield of NO were studied.

RESULTS

The Ad-eNOS can infect the cultured SMC efficiently (MOI = 50, infection rate = 74%). Western blot and RT-PCR confirmed the expression of eNOS in those infected cells. After the cells had been infected with Ad-eNOS, the basal activity of NOS significantly increased from 47±13 nkat/L to 93±13/L (P<0.05), and the level of NO in cell culture supernatants increased by 3 fold (45±13 vs 16±7 μmol/L). In the presence of L-arginine (NOS enzyme substrate), calcium, EGTA (calcium chelating agent), and L-NAME (NOS inhibitor), NOS activity was 94±8, 173±25, 29±6, 58±11 nkat/L and NO level was 48±14, 106±18, 6±2, 17±11 μmol/L, respectively.

CONCLUSION

The constructed recombinant adenovirus, Ad-eNOS, can efficiently mediate the expression of eNOS gene in cultured SMC of digestive tract. The activity of eNOS can be regulated by the concentration of calcium. L-arginine is Not the rate-limiting step for nitric oxide generation from endothelial nitric oxide synthase.

Clinical significance of sphincter of Oddi dyskinesia

Sphincter of Oddi dyskinesia (SOD) is a functional disorder of the papilla region that can lead to clinical symptoms and functional obstruction of biliary and pancreatic outflow. Based on the severity of the clinical symptoms, the disorder is classified as one of three types (biliary or pancreatic type I-III). Diagnosis of SOD is hampered by the relative risk of endoscopic sphincter manometry to cause pancreatitis. Manometrically, SOD is characterized by increased pressure in the biliary or pancreatic sphincter segment and can be treated with endoscopic papillotomy. This review is an attempt to balance the arguments for invasive diagnosis with a pragmatic clinical approach in which papillotomy is performed if clinical suspicion and patient presentation support a dysfunction of the papilla. For patients with biliary or pancreatic type I, endoscopic papillotomy is the treatment of choice. In biliary type II, SO manometry may be helpful for clinical decision making; however, the ratio of risks to benefits is difficult to assess based on the present data. In type III SOD, patient selection and the low predictive value of manometry for treatment success raise questions about the clinical usefulness of SO manometry.

The effects of cholecystojejunostomy and biliary drainage on biliary motor

Simulating physiological neuronal and hormonal conditions during digestive and interdigestive periods, the study identified the changes of the motility of biliary system including bile duct and sphincter of Oddi (SO) before and after cholecystojejunostomy. Thirty-five rabbits were divided into five groups randomly. The experimental groups received the venous injection of CCK 10 ng/kg, erythromycin 10 mg/kg, atropine 3 micrograms/kg and L-NAME 10 mg/kg respectively. Each rabbit underwent manometry through introducing a three-lumen catheter via the papilla retrogradely, using the low-compliance papillary infusion system. Then the gallbladder and the upper segment of the jejunum was anastomosed and the manometric procedures repeated after one week. SO basal pressure was increased, contraction amplitude decreased, contraction time shortened after cholecystojejunostomy. L-NAME, CCK and erythromycin could all excite SO. L-NAME could increase basal pressure and contraction amplitude, CCK increase basal pressure contraction amplitude and frequency, and erythromycin increase contraction amplitude, respectively. But comparing with that before cholecystojejunostomy, the increasing extent was decreased. The tensional and spontaneous contractions of the SO were under the control of the neural and hormonal mechanism. The anastomosis of gallbladder and jejunum and the drainage of bile made the tensional contraction stronger, but the spontaneous contraction weakened after the operation due to the decreases of the sensitivity of SO to hormonal factors. The clinical symptoms may not be relieved when the patients with SO dysfunction accepted cholecystojejunostomy.