Effects of Biliary Tract Pressure on Dynamics of the Oddi's Sphincter and its Nerve Mechanism

In order to explore the effect of binary tract pressure on Oddi's sphincter and the mechanism of development of high pressure of binary tract during acute obstructive and suppurative cholangitis (AOSC), house rabbits were used to establish model of high binary pressure in acute binary duct caecus. It was observed that when the pressure of the acute binary tract was increased to 8 kpa,the electric activity of Oddi's sphincter was obviously enhanced, the pressure of Oddices sphincter increased remarkably (P <0. 05), and even constant spasm appeared with accompanying increase of discharge frequency of the right greater splanchnic nerves (P <0. 05) and progressive decrease of mean arterial pressure.However, when lidocaine of 0. 6 % was used to block the right celiac plexus, no above-mentioned reaction happened when the binary tract pressure was increased again. The results indicated that the acute binary tract obstruction might induce the contraction or spasm of Oddi's sphincter and bring about a vicious cycle. Its mechanism is related to splanchnic nerves reflection and it is one of important factors in the development of AOSC course.

Problems with repairing gut sphincters malfunctions

Correcting a gut sphincter malfunction is a difficult problem.Because each sphincter has two opposite functions,that of closure and opening,repairing one there is a risk of damaging the other.Indeed,widening a narrow sphincter,such as lower esophageal sphincter(LES)and anal sphincter,may cause gastroeso-phageal reflux and fecal incontinence,respectively,whereas narrowing a wide sphincter,may cause a difficult transit.All the corrective treatments for difficult or retrograde transit concerning LES and anal sphincter with their unwanted consequences have been analyzed and discussed.To overcome the drawbacks of sphincter surgical repairs,researchers have devised devices capable of closing and opening the gut lumen,named artificial sphincters(ASs).Their function is based on various mechanisms,e.g.,hydraulic,magnetic,mechanical etc,operating through many complicated components,such as plastic cuffs,balloons,micro-pumps,micromotors,connecting tubes and wires,electromechanical clamps,rechargeable batteries,magnetic devices,elastic bands,etc.Unfortunately,these structures may facilitate the onset of infections and induce a local fibrotic reaction,which may cause device malfunctioning,whereas the compression of the gut wall to occlude the lumen may give rise to ischemia with erosions and other lesions.Some ASs are already being used in clinical practice,despite their considerable limits,while others are still at the research stage.In view of the adverse events of the ASs mentioned above,we considered applying bioengineering methods to analyze and resolve biomechanical and biological interaction problems with the aim to conceive and build efficient and safe biomimetic ASs.

Milligan-Morgan hemorrhoidectomy with anal cushion suspension and partial internal sphincter resection for circumferential mixed hemorrhoids

AIM:To identify a more effective treatment protocol for circumferential mixed hemorrhoids.METHODS:A total of 192 patients with circumferential mixed hemorrhoids were randomized into the treatment group,where they underwent Milligan-Morgan hemorrhoidectomy with anal cushion suspension and partial internal sphincter resection,or the control group,where traditional external dissection and internal ligation were performed.Postoperative recovery and complications were monitored.RESULTS:The time to wound healing was 12.96 ± 2.25 d in the treatment group shorter than 19.58 ± 2.71 d in the control group.Slight pain rate was 58.3% in the treatment group higher than 22.9% in the control group;moderate pain rate was 33.3% in the treatment group lower than 56.3% in the control group severe pain rate was 8.4% in the treatment group lower than 20.8% in the control group.No edema rate was 70.8% in the treatment group higher than 43.8% in the control group;mild local edema rate was 26% in the treatment group lower than 39.6% in the control group obvious local edema was 3.03% in the treatment group lower than 16.7% in the control group.No stenosis rate was 85.4% in the treatment group higher than 63.5% in the control group;moderate stenosis rate was 14.6% in the treatment group Lower than 27.1% in the control group severe anal stenosis rate was 0% in the treatment group lower than 9.4% in the control group.CONCLUSION:Milligan-Morgan hemorrhoidectomy with anal cushion suspension and partial internal sphincter resection is the optimal treatment for circumferential mixed hemorrhoids and can be widely applied in clinical settings.

Dynamic and ultrastructural study of sphincter of Oddi in early-stage cholelithiasis in rabbits with hypercholesterolemia

AIM To study the relationship between pre-formation of gallstone and the kinetics and ultra-structure of sphincter of Oddi.METHODS Adult female rabbits were used anddivided into 3 groups,and fed with either normalor high cholesterol diet for four or eight weeks.Each group contained eight rabbits.Themanometry of sphincter of Oddi,biliarycineradiography,gallbladder volumemeasurement and ultrastructure observationunder electron microscope were performed.RESULTS In groups Ⅰ and Ⅱ,the basalpressure in low-pressure ampulla or highpressure zone of sphincter of Oddi waselevated,the amplitude of phasic contractionwas decreased and the volume of gallbladderwere increased,with a significant difference(P【0.01)from those of control.Gallstones werefound in group Ⅱ rabbits(7/8).Undercineradiography,low-pressure ampulla showeda spasmodic status without apparent peristalticcontraction.Under electron microscope,insidethe muscular cells of sphincter of Oddi,loosening of microfilament and swelling ofplasmosomes which congregated at the top wereobserved.The amount showed no obviouschange under nitric oxide synthase(NOS)stain.CONCLUSION Twisting of the microfilamentand disarrangement of kink macula densa insidethe muscular ceils suggested that the sphincterof Oddi was under spasmodic status.Theimpaired diastolic function caused andaggravated the stasis of cystic bile.Theswelling plasmosome could be one of theimportant factors in elevating the tonic pressureof sphincter of Oddi.

Effects of sphincter of Oddi motility on the formation of cholesterol gallstones

AIM: To investigate the mechanisms and effects of sphincter of Oddi(SO) motility on cholesterol gallbladder stone formation in guinea pigs.METHODS: Thirty-four adult male Hartley guinea pigs were divided randomly into two groups, the control group(n = 10) and the cholesterol gallstone group(n = 24), which was sequentially divided into four subgroups with six guinea pigs each according to time of sacrifice. The guinea pigs in the cholesterol gallstone group were fed a cholesterol lithogenic diet and sacrificed after 3, 6, 9, and 12 wk. SO manometry and recording of myoelectric activity were obtained by a multifunctional physiograph at each stage. Cholecystokinin-A receptor(CCKAR) expression levels in SO smooth muscle were detected by quantitative real-time PCR(q RT-PCR) and serum vasoactive intestinal peptide(VIP), gastrin, and cholecystokinin octapeptide(CCK-8) were detected by enzyme-linked immunosorbent assay at each stage in the process of cholesterol gallstone formation.RESULTS: The gallstone formation rate was 0%, 0%, 16.7%, and 83.3% in the 3, 6, 9, and 12 wk groups, respectively. The frequency of myoelectric activity in the 9 wk group, the amplitude of myoelectric activity in the 9 and 12 wk groups, and the amplitude and the frequency of SO in the 9 wk group were all significantly decreased compared to the control group. The SO basal pressure and common bile duct pressure increased markedly in the 12 wk group, and the CCKAR expression levels increased in the 6 and 12 wk groups compared to the control group. Serum VIP was elevated significantly in the 9 and 12 wk groups and gastrin decreased significantly in the 3 and 9 wk groups. There was no difference in serum CCK-8 between the groups.CONCLUSION: A cholesterol gallstone-causing diet can induce SO dysfunction. The increasing tension of the SO along with its decreasing activity may play an important role in cholesterol gallstone formation. Expression changes of CCKAR in SO smooth muscle and serum VIP and CCK-8 may be important causes of SO dysfunction.

Roles of sphincter of Oddi motility and serum vasoactive intestinal peptide,gastrin and cholecystokinin octapeptide

AIM: To investigate roles of sphincter of Oddi (SO) motility played in pigment gallbladder stone formation in model of guinea pigs.

Sphincter of Oddi laxity:An important factor in hepatolithiasis

AIM:To evaluate the importance of sphincter of Oddi laxity (SOL) in hepatolithiasis (HL).METHODS:Subjects included 98 patients diagnosed with HL between 2002 and 2007. Detailed histories were taken and the subjects were monitored until July 2008. HL patients were divided into two groups:Group included 45 patients with SOL,and Group included 53 patients without. Recurrence and reoperation indices of both groups were calculated and compared.RESULTS:The recurrence index was 0.135 in Group and 0.018 in Group fldex was 0.070 in Group and 0.010 in Group (P <0.001). The mean frequency of biliary operation was 2.07in Group (P = 0.001). Differences between the two groups are significant.CONCLUSION:HL patients with SOL tend to have a higher risk of recurrence and a larger demand for re-operation than those without this condition.

Sphincter of Oddi dysfunction Type Ⅲ: New studies suggest new approaches are needed

Sphincter of Oddi dysfunction(SOD) has been classified into three types based upon the presence or absence of objective findings including liver test abnormalities and bile duct dilatation. Type Ⅲ is the most controversial and is classified as biliary type pain in the absence ofany these objective findings. Many prior studies have shown that the clinical response to endoscopic therapy is higher based upon the presence of these objective criteria. However, there has been variable correlation of the manometry findings to outcome after endoscopic therapy. Nevertheless, manometry and sphincterotomy has been recommended for Type Ⅲ patients given the overall response rate of 33%, although the reported response rates are highly variable. However, all of the prior data was non-blinded and non-randomized with variable follow-up. The evaluating predictors in SOD study- a prospective randomized blinded sham controlled one year outcome study showed no correlation between manometric findings and outcome after sphincterotomy. Furthermore, patients receiving sham therapy had a statistically significantly better outcome than those undergoing biliary or dual sphincterotomy. This study calls into question the whole concept of SOD Type Ⅲ and, based upon prior physiologic studies, one can suggest that SOD Type Ⅲ likely represents a right upper quadrant functional abdominal pain syndrome and should be treated as such.

Oddi sphincter preserved cholangioplasty with hepaticosubcutaneous stoma for hepatolithiasis

AIM: To evaluate the long-term outcomes of Oddi sphincter preserved cholangioplasty with hepaticosubcutaneous stoma(OSPCHS) and risk factors for recurrence in hepatolithiasis.METHODS: From March 1993 to December 2012, 202 consecutive patients with hepatolithiasis underwent OSPCHS at our department. The Oddi sphincter preserved procedure consisted of common hepatic duct exploration, stone extraction, hilar bile duct plasty, establishment of subcutaneous stoma to the bile duct. Patients with recurrent stones can undergo stone extraction and/or biliary drainage via the subcutaneous stoma which can be incised under local anesthesia. The long-term results were reviewed. Cox regression model was employed to analyze the risk factors for stone recurrence.RESULTS: Ninety-seven(48.0%) OSPCHS patients underwent hepatic resection concomitantly. The rate of surgical complications was 10.4%. There was no perioperative death. The immediate stone clearance rate was 72.8%. Postoperative cholangioscopic lithotomy raised the clearance rate to 97.0%. With a median follow-up period of 78.5 mo(range: 2-233 mo), 24.8% of patients had recurrent stones, 2.5% had late development of cholangiocarcinoma, and the mortality rate was 5.4%. Removal of recurrent stones and/or drainage of inflammatory bile via subcutaneous stoma were conducted in 44(21.8%) patients. The clearance rate of recurrent stones was 84.0% after subsequent choledochoscopic lithotripsy via subcutaneous stoma.Cox regression analysis showed that residual stone was an independent prognostic factor for stone recurrence.CONCLUSION: In selected patients with hepatolithiasis, OSPCHS achieves excellent long-term outcomes, and residual stone is an independent prognostic factor for stone recurrence.

Effects of somatostatin analogues on human sphincter of Oddi pressure

BACKGROUND: Somatostatin, a neuropeptide and hor- mone , exists in the biliary tract of several species. The effects of somatostatin and its analogues on the sphincter of Oddi motility have been controversial. The aim of this study was to observe the action of stilamin and sandostatin on the sphincter of Oddi via choledochofiberscope manometry. METHODS: Twenty patients who had had'T' duct after cholecystectomy and choledochotomy were divided into 2 groups randomly: stilamin and sandostatin. They were subjected to manometry via a choledochofiberscope through the'T' duct tract. The following data recorded in- cluded duodenal pressure (DP), sphincter of Oddi basal pressure (SOBP), sphincter of Oddi contractive amplitude (SOCA), frequency of the sphincter of Oddi (SOF), dura- tion of the sphincter of Oddi, and the common bile duct pressure (CBDP). RESULTS: After intravenous administration of stilamin at a dose of 250 μg/h, the mean SOCA increased from 89.18 (26.50) to 128.57(54.21) mmHg (P <0.05). After the ad- ministration of stilamin at a dose of 500 μg/h the mean SO- CA declined to 92.18(42.81) mmHg (P<0.05), and mean SOBP declined from 17.63(13.36) to 8.16(4.01) mmHg (P<0.05). Although SOF had declined from 9.25(2.45) to 7.46(1.52) n/min, it was not significantly influenced. After intravenous administration of sandostatin at a dose of 100 μg, the mean CBDP increased obviously. CONCLUSIONS: Intravenous administration of stilamin at a dose of 250 μg/h stimulates the motility of the sphincter of Oddi whereas the injection of stilamin at a dose of 500 μg/h inhibits its motility. Intravenous injection of sandosta- tin of 100 μg has no effect on the sphincter of Oddi.

Upper esophageal sphincter abnormalities are strongly predictive of treatment response in patients with achalasia

AIM: To investigate the relationship between upper esophageal sphincter abnormalities achalasia treatment METHODS: We performed a retrospective study of 41 consecutive patients referred for high resolution esophageal manometry with a final manometric diagnosis of achalasia. Patients were sub-divided by presence or absence of Upper esophageal sphincter(UES) abnormality, and clinical and manometric profiles were compared.Correlation between UES abnormality and sub-type(i.e.,hypertensive, hypotensive or impaired relaxation) and a number of variables, including qualitative treatment response, achalasia sub-type, co-morbid medical illness,psychiatric illness, surgical history, dominant presentingsymptom, treatment type, age and gender were also evaluated.RESULTS: Among all 41 patients, 24(58.54%) had a UES abnormality present. There were no significant differences between the groups in terms of age, gender or any other clinical or demographic profiles. Among those with UES abnormalities, the majority were either hypertensive(41.67%) or had impaired relaxation(37.5%) as compared to hypotensive(20.83%), although this did not reach statistical significance(P = 0.42). There was no specific association between treatment response and treatment type received; however, there was a significant association between UES abnormalities and treatment response. In patients with achalasia and concomitant UES abnormalities, 87.5% had poor treatment response, while only 12.5% had favorable response. In contrast, in patients with achalasia and no UES abnormalities, the majority(78.57%) had good treatment response, as compared to 21.43% with poor treatment response(P = 0.0001). After controlling for achalasia sub-type, those with UES abnormality had 26 times greater odds of poor treatment response than those with no UES abnormality(P = 0.009). Similarly, after controlling for treatment type, those with UES abnormality had 13.9 times greater odds of poor treatment response compared to those with no UES abnormality(P = 0.017).CONCLUSION: The presence of UES abnormalities in patients with achalasia significantly predicted poorer treatment response as compared to those with normal UES function.

RELATIONSHIP BETWEEN INTERNAL ANAL SPHINCTER FUNCTION AND LENGTH OF REMAINING RECTUM AFTER RESECTING RECTAL CARCINOMA

Objective: To study the relationship between internal anal sphincter function and length of remaining rectum after resecting rectal carcinoma. Methods: Preoperatively, 21 patients were evaluated via patients' clinical date, including anal resting pressure (resting pressure) assay. Six months postoperatively, repeated manometric studies and clinical evaluations were performed to assess the level of continence . The formula use for calculating post operative resting pressure is as follows: postoperative resting pressure=0.42×preoperative resting pressure+1.56×length of remaining recturm+12.37(R 2=0.58; P <0.01).Degree of continence was graded based on severity of the dysfunction and grade of the continence score. Results: It was demonstrated the patients with low postoperative resting pressures (<4.0 Kpa) had incontinence, and those with high postoperative resting pressures (>4.7 Kpa) were continent. There were significant correlations between length of the remaining rectum and ratio of the decrease in maximum resting pressure (postoperative/preoperative maximum resting pressure;r=0.62; P <0.01). Conclusion: Continence of rectum is influenced by maximum resting pressure of function of the internal anal sphincter, length of remaining rectum is shorter, the more damage to the internal anal sphincter. It is able to foretell stool incontinence by using the postoperative resting pressure formula, and to determine the length of the remaining rectum.

Sphincter of Oddi dysfunction and pancreatitis

Sphincter of Oddi dysfunction (SOD) is a term used to describe a group of heterogenous pain syndromes caused by abnormalities in sphincter contractility. Biliary and pancreatic SOD are each sub-classified as typeⅠ,Ⅱ or Ⅲ,according to the Milwaukee classification. SOD appears to carry an increased risk of acute pancreatitis as well as rates of post ERCP pancreatitis of over 30%. Various mechanisms have been postulated but the exact role of SOD in the pathophysiology of acute pancreatitis is unknown. There is also an association between SOD and chronic pancreatitis but it is still unclear if this is a cause or effect relationship. Management of SOD is aimed at sphincter ablation,usually by endoscopic sphincterotomy (ES). Patients with typeⅠSOD will benefit from ES in 55%-95% of cases. Sphincter of Oddi manometry is not necessary before ES in typeⅠ SOD. For patients with types Ⅱ and Ⅲ the benefit of ES is lower. These patients should be more thoroughly evaluated before performing ES. Some researchers have found that manometry and ablation of both the biliary and pancreatic sphincters is required to adequately assess and treat SOD. In pancreatic SOD up to 88% of patients will benefit from sphincterotomy. Therefore,there have been calls from some quarters for the current classification system to be scrapped in favour of an overall system encompassing both biliary and pancreatic types. Future work should be aimed at understanding the mechanisms underlying the relationship between SOD and pancreatitis and identifying patient factors that will help predict benefit from endoscopic therapy.

Sphincter of Oddi dysfunction and bile duct microlithiasis in acute idiopathic pancreatitis

Although there are numerous causes of acute panc-reatitis, an etiology cannot always be found. Two potential etiologies, microlithiasis and sphincter of Oddi dysfunction, are discussed in this review. Gallbladder microlithiasis, missed on transcutaneous ultrasound, is reported as the cause of idiopathic acute pancreatitis in a wide frequency range of 6%-80%. The best diagnostic technique for gallbladder microlithiasis is endoscopic ultrasound although biliary crystal analysis and empiric cholecystectomy remain as reasonable options. In contrast, in patients who are post-cholecystectomy, bile duct microlithiasis does not appear to have a role in the pathogenesis of acute pancreatitis. Sphincter of Oddi dysfunction is present in 30%-65% of patients with idiopathic acute recurrent pancreatitis in whom other diagnoses have been excluded. It is unclear if this sphincter dysfunction was the original etiology of the first episode of pancreatitis although it appears to have a causative role in recurring episodes since sphincter ablation decreases the frequency of recurrent attacks. Unfortunately, this conclusion is primarily based on small retrospective case series; larger prospective studies of the outcome of pancreatic sphincterotomy for SOD-associated acute pancreatitis are sorely needed. Another problem with this diagnosis and its treatment is the concern over potential procedure related complications from endoscopic retrograde cholangiopancreatography (ERCP), manometry and pancreatic sphincterotomy. For these reasons, patients should have recurrent acute pancreatitis, not a single episode, and have a careful informed consent before assessment of the sphincter of Oddi is undertaken.

Effect of morphine and M-cholinoceptor blocking drugs on human sphincter of Oddi during choledochofiberscopy manometry

OBJECTIVE: To evaluate the effects of morphine on the human sphincter of Oddi pressure and the antagonism of anticholinergic agents against morphine. METHODS: The action of these drugs on the sphincter of Oddi (SO) was evaluated by means of choledochofiberscopy manometry in 40 operated patients with T-tube. The patients were divided randomly into 4 groups: anisodamine, atropine, buscopan, and control. The following data were recorded: duodenal pressure (DP), basal pressure of the sphincter of Oddi (BPSO), contractive amplitude of the sphincter of Oddi (CASO), contractive frequency of the sphincter of Oddi (CFSO), contractive duration of the sphincter of Oddi (CDSO), and pressure of the common bile duct (PCBD). Both morphine and anticholinergic agents were given intramuscularly. RESULTS: After injection of 10 mg morphine, BPSO, CASO, CFSO, and PCBD increased significantly. After injection of 15 mg anisodamine or 0.75 mg atropine, CASO, BPSO declined obviously, and after injection of 20 mg buscopan, CASO, BPSO, CFSO declined obviously, but in anisodamine, atropine and buscopan groups, they differed insignificantly. CONCLUSIONS: The results illustrate that SO manometry via choledochofiberscopy is a new method for SO dynamic study. Morphine can increase DP, BPSO, CASO, PCBD, but anisodamine atropine and buscopan can antagonize the effect of morphine.

Sphincter of Oddi dysfunction: Managing the patient with chronic biliary pain

Sphincter of Oddi dysfunction （SOD） is a syndrome of chronic biliary pain or recurrent pancreatitis due to functional obstruction of pancreaticobiliary flow at the level of the sphincter of Oddi. The Milwaukee classification stratifies patients according to their clinical picture based on elevated liver enzymes, dilated common bile duct and presence of abdominal pain. Type Ⅰ patients have pain as well as abnormal liver enzymes and a dilated common bile duct. Type Ⅱ SOD consists of pain and only one objective finding, and Type Ⅲ consists of biliary pain only. This classification is useful to guide diagnosis and management of sphincter of Oddi dysfunction. The current gold standard for diagnosis is manometry to detect elevated sphincter pressure, which correlates with outcome to sphincterotomy. However, manometry is not widely available and is an invasive procedure with a risk of pancreatitis. Non-invasive testing methods, including fatty meal ultrasonography and scintigraphy, have shown limited correlation with manometric findings but may be useful in predicting outcome to sphincterotomy. Endoscopic injection of botulinum toxin appears to predict subsequent outcome to sphincterotomy, and could be useful in selection of patients for therapy, especially in the setting where manometry is unavailable.

Sphincter of Oddi hypomotility and its relationship with duodenal-biliary reflux,plasma motilin and serum gastrin

AIM: To detect whether patients with a T tube after cholecystectomy and choledochotomy have duodenal-biliary reflux by measuring the radioactivity of Tc99m-labeled diethylene triamine penta-acetic acid (DTPA) in the bile and whether the patients with duodenal-biliary reflux have sphincter of Oddi hypomotility, by mea-suring the level of plasma and serum gastrin of the patients. Finally to if there is close relationship among sphincter of Oddi hypomotility, duodenal-biliary reflux and gastrointestinal peptides. METHODS: Forty-five patients with a T tube after cholecystectomy and choledochotomy were divided into reflux group and control group. The level of plasma and serum gastrin of the patients and of 12 healthy volunteers were measured by radioimmunoas-say. Thirty-four were selected randomly to undergo choledochoscope manometry. Sphincter of Oddi basal pressure (SOBP), amplitude (SOCA), frequency of con-tractions (SOF), duration of contractions (SOD), duo-denal pressure (DP) and common bile duct pressure (CBDP) were scored and analyzed. RESULTS: Sixteen (35.6%) patients were detected to have duodenal-biliary reflux. SOBP, SOCA and CBDP in the reflux group were much lower than the controlgroup (t = 5.254, 3.438 and 3.527, P < 0.001). SOD of the reflux group was shorter than the control group (t = 2.049, P < 0.05). The level of serum gastrin and plasma motilin of the reflux group was much lower than the control group (t = -2.230 and -2.235, P < 0.05). There was positive correlation between the level of plasma motilin and SOBP and between the level of serum gastrin and SOBP and CBDP. CONCLUSION: About 35.9% of the patients with a T tube after cholecystectomy and choledochotomy have duodenal-biliary reflux. Most of them have sphincter of Oddi hypomotility and the decreased level of plasma motilin and serum gastrin. The disorder of gastroin-testinal hormone secretion may result in sphincter of Oddi dysfunction. There is a close relationship between sphincter of Oddi hypomotility and duodenal-biliary re-flux.

Interplay between nitric oxide and VIP in CCK-8-induced phasic contractile activity in the rabbit sphincter of Oddi

AIM: The sphincter of Oddi (SO) plays an important role in delivery of bile into the duodenum. To establish whether vasoactive intestinal polypeptide (VIP) and nitric oxide (NO) were involved in phasic contractile activity of the rabbit SO stimulated by cholecystokinin-octapeptide (CCK-8). METHODS: Isolated SO muscle rings were cleaned of fat and mounted horizontally on two small L-shaped hooks one of which was connected to a force transducer for the measurement of isometric tension.The experiments were carried out in a thermostatically controlled (37±0.2℃) organ bath (5 mL) containing Krebs solution.The organ fluid was gassed with 95% O2 and 50 mL/L CO2 to keep the pH at 7.40±0.05. Contractile responses to CCK-8 (1 μmol/L) were evaluated in the presence and absence of NG-nitro-L-arginine (LNNA), an inhibitor of NO synthase (100 μmol/L), and (p-chloro-D-Phe6-Leu17)-VIP (VlPa, 30 μmol/L), a VIP receptor antagonist. RESULTS: CCK-8 stimulated the phasic activity of the SO. NO synthase inhibition increased the frequency and amplitude of contractions with a slight increase in developed tension. Pre-incubation with VlPa also attenuated this CCK-8 effect. The combined application of LNNA and VlPa abolished the phasic activity of the muscle rings with a marked increase in tension in response to CCK-8. CONCLUSION: VIP and NO together contribute to an increase in phasic activity of SO.

Role of intracellular calcium in contraction of internal anal sphincter

ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｔｅｒｎａｌａｎａｌｓｐｈｉｎｃｔｅｒ（ＩＡＳ）ｉｓａｃｏｎｔｉｎｕａｔｉｏｎｏｆｔｈｅｓｍｏｏｔｈｃｉｒｃｕｌａｒｍｕｓｃｌｅｌａｙｅｒｔｈｉｃｋｅｎｅｄａｔｔｈｅｒｅｃｔｕｍ，ｉｎｎｅｒｖａｔｅｄｂｙｖｅｇｅｔａｔｉｖ...

Effects of octreotide on gallbladder pressure and myoelectric activity of Oddi sphincter in rabbits

AIM To observe the effect of octreotide (OT) and somatostatin (SS) on gallbladder pressure and myoelectric activity of SO in rabbits. METHODS Male rabbits fasted for 15h - 18h and anesthetized with urethane. The mean gallbladder pressure (GP) and myoelectric activity of SO were simultaneously measured with a frog bladder connected to a transducer and a pair of copper electrodes. RESULTS After injection of OT (10μg/kg, iv), the GP decreased in 2min and reached the lowest value in about 60min ( P <0 01, n =19), and completely or partially returned to the normal level in 120min. The frequency of myoelectric activity of SO was reduced, even disappeared in 2min ( P <0 01, n =19) and returned to normal in about 20min . Injection of SS (10μg/kg, iv) also decreased GP and myoelectric activity of SO ( P <0 01, n =7); Before and after injection of OT or SS, injection of CCK 8 ( 100ng or 200ng ) caused similar increase in myoelectric activity of SO and GP ( P >0 05). Before and after injection of OT, there were no significant differences in increases of myoelectric activity of SO and GP caused by electric stimulation of dorsal motor nucleus of vagus ( P >0 05). CONCLUSION OT and SS decreased GP and myoelectric activity of SO, demonstrating that effects of OT were similar to those of SS. Intravenous injection of OT did not affect the increase of myoelectric activity of SO and GP caused by CCK 8 or electric stimulation of dorsal motor nucleus of vagus.