Surgical anatomy of innervation of the gallbladder in humans and Suncus murinus with special reference to morphological understanding of gallstone formation after gastrectomy.

AIM: To clarify the innervation of human gallbladder, with special reference to morphological understanding of gallstone formation after gastrectomy. METHODS: The liver, gallbladder and surrounding structures were immersed in a 10 mg/L solution of alizarin red S in ethanol to stain the peripheral nerves in cadavers (n=10). Innervation in the areas was completely dissected under a binocular microscope. Similarly, innervation in the same areas of 10 Suncus murinus (S. murinus) was examined employing whole mount immunohistochemistry. RESULTS: Innervation of the gallbladder occurred predominantly through two routes. One was from the anterior hepatic plexus, the innervation occurred along the cystic arteries and duct. Invariably this route passed through the hepatoduodenal ligament. The other route was from the posterior hepatic plexus, the innervation occurred along the cystic duct ventrally. This route also passed through the hepatoduodenal ligament dorsally. Similar results were obtained in S. murinus. CONCLUSION: The route from the anterior hepatic plexus via the cystic artery and/or duct is crucial for preserving gallbladder innervation. Lymph node dissection specifically in the hepatoduodenal ligament may affect the incidence of gallstones after gastrectomy. Furthermore, the route from the posterior hepatic plexus via the common bile duct and the cystic duct to the gallbladder should not be disregarded. Preservation of the plexus may attenuate the incidence of gallstone formation after gastrectomy.

Pancreatobiliary afferent recordings in the anaesthetised Australian possum.

The sensory innervation to the pancreatobiliary system is poorly characterized. Afferent signals from the gastrointestinal tract and biliary tree are transmitted to the central nervous system via the vagus and spinal nerves. We aimed to record afferent discharge in order to characterize the vagal and splanchnic afferent signals from the possum upper gastrointestinal tract, biliary tree and pancreas. In 21 anaesthetised possums nerve fibres were teased from the vagus or splanchnic nerve for multi-unit recording. Mechanical stimuli consisted of balloon distension of the gallbladder and duodenum (2-7 ml) and fluid distension (0-20 mm Hg) of the bile or pancreatic ducts. Approximately 60% of fibres from all nerves displayed spontaneous discharge. Spinal afferent responses to mechanical stimuli were infrequent (n=13). Increased discharge occurred in response to duodenal (12/99 fibres) or gallbladder (7/96 fibres) distension, but not to bile duct (0/73 fibres) or pancreatic duct (0/51 fibres) distension. Vagal afferent responses to distension of the duodenum or stomach (5-30 ml) were more common (n=8). Increased discharge was recorded in response to duodenal (49/134 fibres), or gastric (22/70 fibres) distension. Responses to gallbladder distension were less frequent (6/99 fibres) and as with the spinal afferent no response to bile duct (0/66) or pancreatic duct (0/70) distension were recorded. We conclude that mechanosensitive afferents in the pancreatobiliary system are relatively rare, particularly within the ducts, and/or that they are adapted to monitor stimuli other than luminal distension.

Thoracic paravertebral block for percutaneous transhepatic biliary drainage.

Percutaneous transhepatic biliary drainage is a painful procedure most commonly performed after intravenous sedation. Despite systemic opiates and benzodiazepines, most patients experience significant pain during the procedure and in the recovery period. Paravertebral blocks allow the spinal nerve roots and sympathetic chain in the paravertebral space to be anesthetized, and their role in providing analgesia for thoracic and upper abdominal surgical procedures is well-established. Herein a case is described in which thoracic paravertebral blockade dramatically reduced standard intra- and postprocedural analgesic needs and provided superior pain control.

Primary malignant peripheral nerve-sheath tumor of the common bile duct.

Primary malignant peripheral nerve-sheath tumors of the common bile duct are extremely rare. To our knowledge, the published literature contains no previous case report of this disease. Here we report on a 58-year-old Japanese woman with a primary malignant peripheral nerve-sheath tumor of the common bile duct, which was completely resected. A hypoechoic mass was identified in the hepatic hilus, using ultrasonography and computed tomography. Endoscopic retrograde cholangiography revealed a smooth stricture and deviation of the common bile duct. Laparotomy exposed a firm mass around the common bile duct that had not invaded the surrounding tissues. Partial resection of the common bile duct and cholecystectomy were performed as the treatment of choice. The final histopathological diagnosis was malignant peripheral nerve-sheath tumor arising from the wall of the common bile duct.

[Obstructive jaundice after cholecystectomy]. / Ictericia obstructiva en mujer colecistectomizada.

In this article we present the case of a 72 year-old woman who three years after laparoscopic cholecystectomy develops obstructive jaundice. An MRI of the liver and biliary system revealed an hiliar mass that caused dilatation of the biliary tree. The patient underwent hepatic duct resection and reconstruction via hepaticojejunostomy. The histological examination of the surgical specimen identified an intramural biliary neuroma with no evidence of malignancy.

Identification of dorsal root ganglion neurons that innervate the common bile duct of rats.

Pain originating in the bile duct is common and many patients who have suffered from it report that it is one of the most intense forms of pain that they have experienced. Many uncertainties remain about the mechanisms underlying pain originating in the bile duct. For example, the dorsal root ganglion (DRG) neurons that give rise to the sensory innervation of the common bile duct (CBD) have not been identified and examined in any species. The goal of the present study was to determine the number, distribution, and size of DRG neurons that innervate the CBD in rats. Injections of WGA-HRP or CTB-HRP were restricted to the lumen of the bile duct. Injections of WGA-HRP labeled a mean number of about 500 DRG neurons bilaterally throughout all thoracic and upper lumbar levels. Injections of CTB-HRP labeled smaller numbers of DRG neurons. Application of colchicine onto the surface of the CBD reduced the number of cells labeled following injections of WGA-HRP into the lumen of the CBD by roughly 86%, suggesting that tracer had not spread in large amounts out of the CBD and labeled afferent fibers in other tissues. Approximately 85% of the neurons labeled with WGA-HRP had cell bodies that were classified as small; the remainder were medium in size. Injections of CTB-HRP labeled cell bodies of varying sizes, including a few large diameter cell bodies. These results indicate that a large number of primarily small DRG cells, located bilaterally at many segmental levels, provide a rich innervation of the common bile duct.

Evidence that tachykinins are the main NANC excitatory neurotransmitters in the guinea-pig common bile duct.

Application of electrical field stimulation (EFS; trains of 10 Hz, 0.25 ms pulse width, supramaximal voltage for 60 s) to the guinea-pig isolated common bile duct pretreated with atropine (1 microM), produced a slowly-developing contraction ('on' response) followed by a quick phasic 'off' contraction ('off peak' response) and a tonic response ('off late' response), averaging 16+/-2, 73+/-3 and 20+/-4% of the maximal contraction to KCl (80 mM), n=20 each, respectively. Tetrodotoxin (1 microM; 15 min before) abolished the overall response to EFS (n 8). Neither in vitro capsaicin pretreatment (10 microM for 15 min), nor guanethidine (3 microM, 60 min before) affected the excitatory response to EFS (n 5 each), showing that neither primary sensory neurons, nor sympathetic nerves were involved. Nomega-nitro-L-arginine (L-NOARG, 100 microM, 60 min before) or naloxone (10 microM, 30 min before) significantly enhanced the 'on' response (294+/-56 and 205+/-25% increase, respectively; n=6-8, P<0.01) to EFS. The combined administration of L-NOARG and naloxone produced additive enhancing effects (655+/-90% increase of the 'on' component, n = 6, P<0.05). The tachykinin NK2 receptor-selective antagonist MEN 11420 (1 microM) almost abolished both the 'on' and 'off late' responses (P<0.01: n=5 each) to EFS, and reduced the 'off-peak' contraction by 55+/-8% (n=5, P<0.01). The subsequent administration of the tachykinin NK1 receptor-selective antagonist GR 82334 (1 microM) and of the tachykinin NK3 receptor-selective antagonist SR 142801 (30 nM), in the presence of MEN 11420 (1 microM), did not produce any further inhibition of the response to EFS (P>0.05; n=5 each). At 3 microM, GR 82334 significantly reduced (by 68+/-9%, P<0.05, n=6) the 'on' response to EFS. The contractile 'off peak' response to EFS observed in the presence of both MEN 11420 and GR 82334 (3 microM each) was abolished (P<0.01; n=6) by the administration of the P2 purinoceptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS, 30 microM). PPADS (30 microM) selectively blocked (75+/-9 and 50+/-7% inhibition, n = 4 each) the contractile responses produced by 100 and 300 microM ATP. Tachykinin-containing nerve fibres were detected by using immunohistochemical techniques in all parts of the bile duct, being distributed to the muscle layer and lamina propria of mucosa. In the terminal part of the duct (ampulla) some labelled ganglion cells were observed. In conclusion, this study shows that in the guinea-pig terminal biliary tract tachykinins, released from intrinsic neuronal elements, are the main NANC excitatory neurotransmitters, which act by stimulating tachykinin NK2 (and possibly NK1) receptors. ATP is also involved as excitatory neurotransmitter. Nitric oxide and opioids act as inhibitory mediators/modulators in this preparation.

Cholecysto-sphincter inhibitory reflex: identification of a reflex and its role in bile flow in a canine model.

To study the effect of gallbladder (GB) distension on the sphincter of Oddi (SO), 9 mongrel dogs (mean weight 15.3+/-3.6 kg) were studied. Under anesthesia, the abdomen was opened and the GB and SO were exposed. A balloon-tipped catheter was introduced into the GB and a manometric catheter into the common bile duct so that its fluoroscopically controlled tip lay within the SO. The pressure response of the GB and SO to GB distension by the balloon without and with selective anesthetization of the GB and SO was recorded. The test was repeated in four vagotomized dogs. GB distension effected pressure rise within the GB and pressure drop within the SO. The GB pressure increased progressively as the distending volume increased, while the SO pressure drop was not affected. Selective anesthetization of the GB or the SO produced no SO pressure changes upon GB distension. The SO pressure response to GB distension after vagotomy was similar to that before vagotomy. The SO relaxation on GB contraction, being reproducible and abolished by selective anesthetization of either the SO or the GB, postulates a reflex relationship that we call the cholecysto-sphincter inhibitory reflex. This reflex seems to regulate the bile flow from the GB to the duodenum through the SO.

Inhibitory NANC neurotransmission in choledocho-duodenal junction of rabbits--a possible role of PACAP.

The pharmacological properties of non-adrenergic non-cholinergic (NANC) inhibitory neurotransmission were investigated in the rabbit choledocho-duodenal junction (CDJ), using the microelectrode and tension recording methods. L-NAME (10(-4) M) and apamin (5 X 10 (-6) M) suppressed NANC relaxation evoked by electrical field stimulation (EFS) in the presence of atropine and guanethidine (each 10(-6) M) to a similar extent (to about 40% of the initial control). However, combined application of L-NAME (10(-4) M) and apamin (5 X 10(-6) M) did not abolish it. EFS also evoked biphasic inhibitory junction potentials (IJPs) consisting of initial fast and slow sustained components in the presence of atropine and guanethidine (each 10(-6) M). Apamin (5 X 10(-8)-5 X 10(-6) M) dose-dependently suppressed the initial fast component by about 70%. In contrast, L-NAME (10(-4) M) did not affect either the amplitude of IJP or the resting membrane potential. PACAP-38 (> 10(-8) M) dose-dependently hyperpolarized the smooth muscle membrane of rabbit CDJ followed by a slow repolarization to the original level. After pretreatment with apamin (5 X 10(-7) M), PACAP-38 (10(-6) M) failed to evoke membrane hyperpolarization. During repolarization in the continued presence of PACAP-38, the amplitude of initial fast component of IJP was reduced to about 40-60% of control value, while that of the slow one was unaffected. A similar suppression of initial fast component of IJP (about 40% of the control value) also occurred after application of PACAP (6-38), a PACAP antagonist, or prolonged treatment with monoclonal antibodies to PACAP-27 or PACAP-38. Furthermore, the substantial part of residual fast IJP in the presence of PACAP (6-38) was suppressed by desensitization to alpha,beta-methylene ATP (10(-3) M). These results indicate that in rabbit CDJ NANC relaxation consists mainly of apamin- and L-NAME-sensitive components, which occur in a membrane potential dependent (through membrane hyperpolarization) and independent fashion, respectively. It has further been suggested that PACAP, together with a smaller contribution of ATP, may be involved as the principal apamin-sensitive transmitter in NANC relaxation of this muscle.

Somatostatin stimulates the brush-tailed possum sphincter of Oddi in vitro and in vivo.

BACKGROUND & AIMS: Somatostatin, a neuropeptide and hormone, is found in the biliary tract of several species. The aim of this study was to map the distribution of somatostatin-like immunoreactive nerve fibers in the extrahepatic biliary tract of the Australian possum and to determine the pharmacological effects of somatostatin 1-14 on sphincter of Oddi activity in vitro and in vivo. METHODS: Tissue was harvested for immunohistochemistry and sphincter of Oddi for circular or longitudinal muscle contractility. In anesthetized possums, sphincter of Oddi motility was measured by manometry, and transsphincteric flow was measured gravimetrically. RESULTS: Somatostatin immunoreactivity was evident in gallbladder ganglia nerve cell bodies and in nerve fibers of the common bile duct and sphincter of Oddi. Somatostatin 1-14 increased circular and longitudinal muscle contraction amplitude 3-4-fold (P < 0.05), but only the longitudinal muscle contraction amplitude was tetrodotoxin sensitive. Somatostatin 1-14 stimulated spontaneous sphincter of Oddi motility in a tetrodotoxin-insensitive manner, increasing basal pressure, contraction frequency, and amplitude 2-4-fold (P < 0.05) and reducing transsphincteric flow to 25% of control (P < 0.0001). CONCLUSIONS: Somatostatin-like immunoreactivity is present in the extrahepatic biliary tree, and somatostatin 1-14 stimulates sphincter of Oddi smooth muscle and nerves. The major action is direct stimulation of sphincter of Oddi circular muscle, which reduces transsphincteric flow.

A traumatic neuroma associated with obstructive jaundice after laparoscopic cholecystectomy.

A traumatic neuroma of the biliary tract is rarely associated with biliary obstruction. The authors describe a case of obstructive jaundice that occurred after laparoscopic cholecystectomy. Obstructive jaundice developed in a 39-year-old woman 8 months after laparoscopic cholecystectomy. The stricture was resected and a Rouxen-Y hepaticojejunostomy was performed. Histological examination revealed a traumatic neuroma and a fibrous scar around the biliary duct. To our knowledge, a traumatic neuroma of the biliary tract after laparoscopic cholecystectomy has not been reported previously. Thermal injury may cause the late onset of a fibrous scar and traumatic neuroma. Therefore, traumatic neuroma should be included in the differential diagnosis when late-onset biliary tract obstruction develops after laparoscopic cholecystectomy.

Rat common bile duct: structure, pharmacological responsiveness, CGRP innervation, and binding sites.

The wall of the rat common bile duct (CBD) consists of several epithelial ducts embedded in connective tissue which contains some regions with cells weakly stained by an antibody against alpha smooth muscle actin. The hepatic side (HS) is more vascularized than the duodenal side (DS). Calcitonin gene-related peptide (CGRP)-like immunoreactivity is present in nerve fibres penetrating deeply into the CBD wall. On whole-mount preparations, CGRP innervation is mainly associated with blood vessels in the HS, whereas it forms a wide meshed network independent of vasculature in the DS. Abundance of CGRP innervation was compared between both sexes and at different ages. No differences were found in the total number of fibres between males and females except at 4 months of age, when males had statistically more abundant innervation than females. However, during aging, while the abundance of innervation (fibers/mm) remained stable in both HS and DS in females, it significantly decreased in males. Autoradiography demonstrated the presence of 125I-CGRP binding sites in the rat CBD. In vitro, 30% of HS strips showed spontaneous rhythmic contractions but all the strips (autocontractile or not) contracted dose dependently in response to acetylcholine (Ach) or substance P (SP). However, DS strips were neither autocontractile nor responsive to Ach or SP. Perfusion of all strips with 10(-7) M CGRP produced no effects nor influenced Ach- or SP-induced contractions.

Neuropeptides in pig sphincter of Oddi, bile duct, gallbladder, and duodenum.

To better understand the complex structure and function of the sphincter of Oddi (SO), the occurrence and localization of nine neuropeptides, including vasoactive intestinal polypeptide (VIP), bombesin, neuropeptide Y, peptide histidine-isoleucine (PHI), calcitonin gene-related peptide (CGRP), galanin, substance P, serotonin, and somatostatin, were studied by immunohistochemical methods in the pig SO. The SO innervation was compared to gallbladder, common bile duct, and duodenal innervation. Specimens from the SO, gallbladder, common bile duct, and duodenum demonstrated a rich network of nerves, as suggested by light microscopy and confirmed by a myelin marker S-100. SO demonstrated very strong immunoreactivity for VIP, strong immunoreactivity for neuropeptide Y and galanin, moderate immunoreactivity for PHI and CGRP, and borderline immunoreactivity for bombesin and substance P. Serotonin and somatostatin immunoreactivity was also observed, not in the nerves, but in some of the epithelial cells. The gallbladder innervation was virtually identical to the SO innervation, whereas common bile duct and duodenal innervation were slightly different. To our knowledge this is the first time that galanin- and PHI-like immunoreactivities have been observed in the SO. Our observations suggest that these peptides, along with VIP, neuropeptide Y, and CGRP, might play a role in the neural control of biliary motility.

Muscarinic receptor subtypes of guinea-pig common bile duct.

The antagonism of carbachol-induced contractions of guinea-pig common bile duct smooth muscle strips by various antagonists has been investigated in order to find out the muscarinic receptor subtype(s) of common bile duct smooth muscle. Atropine, pirenzepine, 4-DAMP and AF-DX 116 were used as nonselective, M1-selective, M1- and M3-selective and M2-selective muscarinic antagonists, respectively. All muscarinic antagonists examined displaced the concentration-response curves to the right, parallelly and in a concentration-dependent manner, without affecting maximum response. Schild analysis of data was consistent with competitive antagonism. pA2 values of the antagonists were as follows: atropine, 9.59; pirenzepine, 7.32; 4-DAMP, 8.99; AF-DX 116, 6.85. When these pA2 values are compared with those obtained in the ileum, it may be concluded that the muscarinic receptors of the guinea-pig common bile duct mediating cholinomimetic-induced contractions, are of the M3 subtype, but not of the M1 and M2 subtypes.

Nerve-mediated contractile and electrical activity of the guinea-pig choledocho-duodenal junction.

The intrinsic motor innervation of the guinea-pig choledocho-duodenal junction was investigated by recording the contractile and intracellular electrical activity of smooth muscle from different regions of this tissue. Electrical transmural nerve stimulation evoked phasic contractions in rings of muscle from the ampulla (0.45 s-1) and tonic contractions in rings of muscle from the choledochal sphincter. Intracellular microelectrode recordings from muscle strips from these two regions revealed that excitatory junction potentials (peak amplitude 7 mV) evoked by transmural nerve stimulation were more conspicuous in muscle strips from the choledochal sphincter, but inhibitory junction potentials (peak amplitude 13 mV) were of larger amplitude in muscle strips from the ampulla. Contractions and membrane depolarization evoked by transmural nerve stimulation were sensitive to 1.4 microM atropine and abolished by 3.1 microM tetrodotoxin. Histological studies on the choledocho-duodenal junction also revealed that the distribution of smooth muscle was non-uniform along the tissue. These results suggest that the two regions may have different functions in the motility of the choledocho-duodenal junction.

Choledochal cysts. Oligoganglionosis in the narrow portion of the choledochus.

To investigate whether cystic dilation may be due to a reduction of postcholinergic cell bodies that leads to autonomic dysfunction, ganglion cell bodies were counted in five patients with choledochal cysts and five patients with normal choledochus. In the normal choledochus, the ganglion cell counts in the proximal and distal portions were 374.7 +/- 82.7/cm2 and 349.2 +/- 51.2/cm2, respectively. In cases of choledochal cysts, the ganglion cell counts in the dilated portion and narrow portions were 298.6 +/- 86.9/cm2 and 81.0 +/- 34.8/cm2, respectively. The cell ratio (narrow to dilated) was 0.271. Significant reductions of cell numbers were observed in all the choledochal cysts having various types of pancreatobiliary junctions. These findings indicate that the reduction in the number of ganglion cells in the narrow portion of the choledochal cysts supports the concept of oligoganglionosis in distal choledochus.

Cholecystectomy in the cat damages pericholedochal nerves and impairs reflex regulation of the sphincter of Oddi. A mechanism for postcholecystectomy biliary dyskinesia.

A recent study demonstrated the activity of the feline sphincter of Oddi to be regulated by the distending pressure in the biliary tract via inhibitory nerves running along the common bile duct. In the present study this mechanism was investigated in cats previously subjected to cholecystectomy. An increment in the hydrostatic pressure in the biliary tree from 0 to 20 cmH2O did not affect the function of the sphincter of Oddi in cholecystectomized cats, but relaxed the sphincter in controls and in cats with sham operation. Morphologic study of the nerve arrangement in the feline extrahepatic biliary tract revealed that cholecystectomy is likely to damage pericholedochal nerves. These experimental observations may have relevance for the development of biliary dyskinesia following cholecystectomy in some patients, and suggest that when performing biliary-tract surgery it is important to preserve nerve fibers running along the common bile duct.

Choledochal cyst. Its possible autonomic involvement in the bile duct.

The properties of the choledochal cyst were compared with those of the normal common bile duct. Cholecystokinin-octapeptide and a high concentration of acetylcholine produced smaller contractions in the strips of the narrow portion of the cyst than in the strips of the dilated portion and the normal common bile duct. Nicotine did not cause contractions in the strip of the narrow portion of the cyst. gamma-Aminobutyric acid (GABA) induced atropine-sensitive, tetrodotoxin-sensitive contractions in the bile ducts through bicuculline-sensitive, furosemide-sensitive GABAA receptors located on the postganglionic cholinergic neuron. The GABA did not induce contractions in the narrow portion of the cyst. The number of ganglion cells was decreased markedly in the same portion. These findings suggest that the choledochal cyst has postganglionic neural dysfunction. This character may be one of the causes of cyst formation.

Differential distribution of vagal afferent neurons from the rat liver.

Selective injection of horseradish peroxidase (HRP) into the left and median lobes (LM) and into the right and caudate (RC) lobes of the liver is followed by labeling of neuronal somata in the right and left nodose ganglia. The size distribution of the labeled neuronal population shows that the afferent neurons from the two parts of the liver can be grouped in two corresponding classes; a third class is apparent following injection into the LM lobes. Small neurons are more numerous after injection into the LM lobes, whereas large ones are labeled in the left nodose ganglion after injection into the RC lobes. It is suggested that the two parts of the liver may have a different functional role in conveying afferent signals.