Characterization of Prognostic Factors and the Efficacy of Adjuvant S-1 Chemotherapy in Patients with Post-surgery Extrahepatic Bile Duct Cancer.

BACKGROUND/AIM: There is no clear consensus on the type of adjuvant therapy that should be used for patients with extrahepatic bile duct cancer. PATIENTS AND METHODS: Two hundred and seventy-one patients that had undergone surgical resection for extrahepatic bile duct cancer composed the study cohort. Demographics, treatments, and relationships between the potential prognostic factors and survival rates were analyzed. RESULTS: The overall 3-year and 5-year survival rates for post-surgery extrahepatic bile duct cancer patients were 49.0% and 35.4%, respectively. Multivariate analysis revealed that regional lymph node metastasis was an independent negative prognostic factor. We observed a significant correlation between node-positive extrahepatic bile duct cancer and postoperative local recurrence, liver metastasis, peritoneal dissemination, and post-surgery lymph node metastasis. Adjuvant S-1 chemotherapy showed a favorable hazard ratio in patients with lymph node metastases or positive vascular invasion. CONCLUSION: We recommend the use of adjuvant S-1 therapy in patients with lymph node metastases or microvascular invasion.

Clinical Implications of Cytotoxic T Lymphocyte Antigen-4 Expression on Tumor Cells and Tumor-Infiltrating Lymphocytes in Extrahepatic Bile Duct Cancer Patients Undergoing Surgery Plus Adjuvant Chemoradiotherapy.

BACKGROUND: There currently is only limited knowledge on the role of tumor-specific immunity in cholangiocarcinoma. OBJECTIVE: This study evaluated the clinical implications of cytotoxic T lymphocyte antigen-4 (CTLA-4) expression levels and CD4+ and CD8+ tumor-infiltrating lymphocytes (TILs) in extrahepatic bile duct (EHBD) cancer. PATIENTS AND METHODS: Immunohistochemistry of CTLA-4, CD4, and CD8 was performed for 77 EHBD cancer patients undergoing surgery plus adjuvant chemoradiotherapy. CTLA-4 expression on tumor cells and TILs were assessed by using H-scores and the proportion of CTLA-4+ lymphocytes, respectively. RESULTS: With optimal cutoff values determined by a maximal chi-square method with overall survival (OS) data, patients with CTLA-4 H-score >70 and a proportion of CTLA-4+ TILs >0.15 showed higher mean density of CD8+ and CD4+ TILs, respectively (P = 0.025 for CD8+ and P = 0.055 for CD4+ TILs). The high CTLA-4 H-score level was associated with prolonged OS and disease-free interval (DFI) (P = 0.025 and 0.004, respectively). With differential levels of CTLA-4 H-score according to hilar and non-hilar locations (high rate 32 vs. 68%, respectively; P = 0.013), an exploratory subgroup analysis demonstrated that the associations between the CTLA-4 expression and OS and DFI were confined to hilar tumors (P = 0.003 and <0.001, respectively), but not to non-hilar ones (P = 0.613 and 0.888, respectively). CONCLUSIONS: This study demonstrates a potential prognostic relevance of CTLA-4 expression in EHBD cancer. We suggest a differential survival impact of the CTLA-4 expression level according to different tumor locations.

The toxin biliatresone causes mouse extrahepatic cholangiocyte damage and fibrosis through decreased glutathione and SOX17.

UNLABELLED: Biliary atresia, the most common indication for pediatric liver transplantation, is a fibrotic disease of unknown etiology affecting the extrahepatic bile ducts of newborns. The recently described toxin biliatresone causes lumen obstruction in mouse cholangiocyte spheroids and represents a new model of biliary atresia. The goal of this study was to determine the cellular changes caused by biliatresone in mammalian cells that ultimately lead to biliary atresia and extrahepatic fibrosis. We treated mouse cholangiocytes in three-dimensional (3D) spheroid culture and neonatal extrahepatic duct explants with biliatresone and compounds that regulate glutathione (GSH). We examined the effects of biliatresone on SOX17 levels and determined the effects of Sox17 knockdown on cholangiocytes in 3D culture. We found that biliatresone caused disruption of cholangiocyte apical polarity and loss of monolayer integrity. Spheroids treated with biliatresone had increased permeability as shown by rhodamine efflux within 5 hours compared with untreated spheroids, which retained rhodamine for longer than 12 hours. Neonatal bile duct explants treated with the toxin showed lumen obstruction with increased subepithelial staining for α-smooth muscle actin and collagen, consistent with fibrosis. Biliatresone caused a rapid and transient decrease in GSH, which was both necessary and sufficient to mediate its effects in cholangiocyte spheroid and bile duct explant systems. It also caused a significant decrease in cholangiocyte levels of SOX17, and Sox17 knockdown in cholangiocyte spheroids mimicked the effects of biliatresone. CONCLUSION: Biliatresone decreases GSH and SOX17 in mouse cholangiocytes. In 3D cell systems, this leads to cholangiocyte monolayer damage and increased permeability; in extrahepatic bile duct explants, it leads to disruption of the extrahepatic biliary tree and subepithelial fibrosis. This mechanism may be important in understanding human biliary atresia. (Hepatology 2016;64:880-893).

Surgery Alone Versus Surgery Followed by Chemotherapy and Radiotherapy in Resected Extrahepatic Bile Duct Cancer: Treatment Outcome Analysis of 336 Patients.

PURPOSE: This study analyzed the outcomes of patients with resected extrahepatic bile duct cancer (EHBDC) in order to clarify the role of adjuvant treatments in these patients. MATERIALS AND METHODS: A total of 336 patients with EHBDC who underwent curative resection between 2001 and 2010 were analyzed retrospectively. The treatment types were as follows: surgery alone (n=168), surgery with chemotherapy (CTx, n=90), surgery with radiotherapy (RT) alone (n=29), and surgery with chemoradiotherapy (CRT, n=49). RESULTS: The median follow-up period was 63 months. The 5-year rates of locoregional failure-free survival (LRFFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival (OS) for all patients were 56.5%, 59.7%, 36.6%, and 42.0%, respectively. In multivariate analysis, surgery with RT and CRT was a significant prognostic factor for LRFFS, and surgery with CTx was a significant prognostic factor for DMFS, and surgery with CTx, RT, and CRT was a significant prognostic factor for PFS (p < 0.05). Surgery with CTx and CRT showed association with superior OS (p < 0.05), and surgery with RT had marginal significance (p=0.078). In multivariate analysis of the R1 resection patients, surgery with CRT showed significant association with OS (p < 0.05). CONCLUSION: Adjuvant RT and CTx may be helpful in improving clinical outcomes of patients with resected EHBDC who have a high risk of disease recurrence, particularly R1 resection patients. Conduct of additional prospective, larger-scale studies will be required in order to confirm the benefit of adjuvant RT and CTx in these patients.

Development and functional characterization of extrahepatic cholangiocyte lines from normal rats.

BACKGROUND: Since limited in vitro tools exist for evaluating the pathophysiology of extrahepatic bile ducts, we aim to develop an extrahepatic cholangiocyte culture system from normal rats. METHODS: Extrahepatic ducts were dissected from rats, cut in half length-wise and cultured on collagen-I coated plates. Transepithelial electrical resistance was measured. At ∼85% confluence, in extrahepatic cholangiocytes we measured: (i) cell size and distribution, and expression for cytokeratin-19, secretin, secretin receptor and somatostatin receptor type II (SSTR2), cystic fibrosis transmembrane conductance regulator (CFTR), chloride bicarbonate anion exchanger 2 (AE2), vascular endothelial growth factor-A (VEGF-A) and nerve growth factor (NGF); and (ii) the effect of secretin and/or somatostatin on 3'-5'-cyclic adenosine monophosphate (cAMP) levels and proliferation. RESULTS: Cytokeratin-positive extrahepatic cholangiocytes were cultured for 6 passages to form a cell monolayer. Cholangiocytes proliferated to confluence over a 2-week period. The size of extrahepatic cholangiocytes averaged ∼16 µm. Extrahepatic ducts and cholangiocytes were positive for secretin, secretin receptor and SSTR2, CFTR, AE2, VEGF-A and NGF. In extrahepatic cholangiocyte cultures, secretin increased cAMP (prevented by somatostatin), chloride efflux and proliferation. CONCLUSIONS: Extrahepatic cholangiocyte cultures may be important for studying diseases targeting extrahepatic cholangiocytes such as biliary atresia.

Feasibility and efficacy of gemcitabine plus cisplatin combination therapy after curative resection for biliary tract cancer.

BACKGROUND: The aim of this multi-institutional study was to assess the feasibility and the efficacy of gemcitabine plus cisplatin (CDDP) combination therapy (GC therapy) for biliary tract cancer (BTC) in the adjuvant setting. METHODS: Eligible patients identified between January 2008 and January 2013 were enrolled. GC therapy at 1,000 mg/m(2) of gemcitabine and 25 mg/m(2) of CDDP on days 1 and 8 repeated every 3 weeks was performed for 6 months. The primary endpoint was the feasibility and the adverse events, and the secondary endpoint was recurrence-free survival (RFS) and overall survival (OS). RESULTS: Among 29 evaluable patients, the protocol was completed in 21 (72%) patients. Relative dose intensity (RDI) of gemcitabine and CDDP was 77% and 81%, respectively. There was no difference in the completion rate and the RDI between patients who underwent resection with vs. without major hepatectomy. Grade 3-4 toxicities included leukopenia (14%) and neutropenia (27%). Two-year RFS and 2-year OS was 59% and 90%, respectively. CONCLUSIONS: Standard dose of GC therapy is tolerable in patients with BTC who underwent curative resection either with or without major hepatectomy. The survival effect of this regimen is promising, but further comparative study is needed.

Activation of the renin-angiotensin system stimulates biliary hyperplasia during cholestasis induced by extrahepatic bile duct ligation.

Cholangiocyte proliferation is regulated in a coordinated fashion by many neuroendocrine factors through autocrine and paracrine mechanisms. The renin-angiotensin system (RAS) is known to play a role in the activation of hepatic stellate cells and blocking the RAS attenuates hepatic fibrosis. We investigated the role of the RAS during extrahepatic cholestasis induced by bile duct ligation (BDL). In this study, we used normal and BDL rats that were treated with control, angiotensin II (ANG II), or losartan for 2 wk. In vitro studies were performed in a primary rat cholangiocyte cell line (NRIC). The expression of renin, angiotensin-converting enzyme, angiotensinogen, and angiotensin receptor type 1 was evaluated by immunohistochemistry (IHC), real-time PCR, and FACs and found to be increased in BDL compared with normal rat. The levels of ANG II were evaluated by ELISA and found to be increased in serum and conditioned media of cholangiocytes from BDL compared with normal rats. Treatment with ANG II increased biliary mass and proliferation in both normal and BDL rats. Losartan attenuated BDL-induced biliary proliferation. In vitro, ANG II stimulated NRIC proliferation via increased intracellular cAMP levels and activation of the PKA/ERK/CREB intracellular signaling pathway. ANG II stimulated a significant increase in Sirius red staining and IHC for fibronectin that was blocked by angiotensin receptor blockade. In vitro, ANG II stimulated the gene expression of collagen 1A1, fibronectin 1, and IL-6. These results indicate that cholangiocytes express a local RAS and that ANG II plays an important role in regulating biliary proliferation and fibrosis during extraheptic cholestasis.

Chemoradiotherapy for extrahepatic bile duct cancer with gross residual disease after surgery.

BACKGROUND: The purpose of the present study was to analyze the outcome of chemoradiotherapy for extrahepatic bile duct (EHBD) cancer patients with gross residual disease after surgical resection. PATIENTS AND METHODS: We retrospectively analyzed 30 patients with EHBD adenocarcinoma who underwent chemoradiotherapy after palliative resection (R2 resection). Postoperative radiotherapy was delivered to the tumor bed including residual tumor and regional lymph nodes (range=40-55.8 Gy). Most patients underwent chemoradiotherapy concurrently with 5-fluorouracil (5-FU) or gemcitabine. RESULTS: The 2-year locoregional progression-free, distant metastasis-free and overall survival rates were 33.3%, 42.4% and 44.5%, respectively. High radiation dose≥50 Gy had a marginally significant impact on superior locoregional progression-free survival compared to 40 Gy (p=0.081). One patient developed grade 3 late gastrointestinal toxicity. CONCLUSION: Adjuvant chemoradiotherapy for EHBD cancer patients with gross residual disease after surgery was well-tolerated. There could be a chance for durable locoregional control and even long-term survival in selected patients.

Influence of glutamine on morphological and functional changes of liver in the presence of extrahepatic biliary obstruction in rats.

PURPOSE: To study the influence of glutamine on functional and morphological changes of liver in the extrahepatic biliary obstruction through an experimental model in rats. METHODS: Seventy Wistar rats were divided into four groups: control (group C) fictitious operation, (group FO), submitted to laparotomy with handling of bile ducts, but without hepatic duct ligation, (group EBO) submitted to laparotomy and hepatic duct ligation, one of them submitted to supplementation with glutamine 2% (group G). The control group consisted of 6 animals. The animals from groups FO, EBO and G were divided into three groups consisting of 6 animals each, being sacrificed at 7, 14 and 21 days after operation, respectively. Blood samples were collected for biochemical analysis and a fragment of liver tissue was collected from the middle lobe for histological analysis. RESULTS: Both for biochemical analysis (BT, aspartate and alanine aminotransferase AST, ALT and alkaline phosphatase FAL) and for histopathological changes (fibrosis, portal inflammation, parenchymal inflammation, hepatocytic changes and duct proliferation), no statistical difference between groups submitted to extrahepatic biliary obstruction (EBO) with and without treatment with glutamine (G) was observed. CONCLUSION: Glutamine supplementation did not alter the prognosis of liver enzymes and histopathological changes in animals submitted to extrahepatic biliary obstruction.

Influence of glutamine on morphological and functional changes of liver in the presence of extrahepatic biliary obstruction in rats / Influência da glutamina em alterações funcionais e morfológicas do fígado na vigência de obstrução biliar extra-hepática em ratos

PURPOSE: To study the influence of glutamine on functional and morphological changes of liver in the extrahepatic biliary obstruction through an experimental model in rats. METHODS: Seventy Wistar rats were divided into four groups: control (group C) fictitious operation, (group FO), submitted to laparotomy with handling of bile ducts, but without hepatic duct ligation, (group EBO) submitted to laparotomy and hepatic duct ligation, one of them submitted to supplementation with glutamine 2 percent (group G). The control group consisted of 6 animals. The animals from groups FO, EBO and G were divided into three groups consisting of 6 animals each, being sacrificed at 7, 14 and 21 days after operation, respectively. Blood samples were collected for biochemical analysis and a fragment of liver tissue was collected from the middle lobe for histological analysis. RESULTS: Both for biochemical analysis (BT, aspartate and alanine aminotransferase AST, ALT and alkaline phosphatase FAL) and for histopathological changes (fibrosis, portal inflammation, parenchymal inflammation, hepatocytic changes and duct proliferation), no statistical difference between groups submitted to extrahepatic biliary obstruction (EBO) with and without treatment with glutamine (G) was observed. CONCLUSION: Glutamine supplementation did not alter the prognosis of liver enzymes and histopathological changes in animals submitted to extrahepatic biliary obstruction.

OBJETIVO: Estudar a influência da glutamina em alterações funcionais e morfológicas do fígado na obstrução biliar extra-hepática por meio de um modelo experimental desenvolvido em ratos. MÉTODOS: Setenta ratos Wistar distribuídos em quatro grupos: controle (grupo C); operação fictícia (grupo OF), submetido à laparotomia com manuseio das vias biliares, mas sem ligadura do ducto hepático; (grupo OBE), submetido à laparotomia exploradora e ligadura do ducto hepático, sendo um deles submetido à suplementação com glutamina a 2 por cento (grupo G). O grupo controle era composto por seis animais. Os animais dos grupos OF, OBE e G foram divididos em três grupos compostos por seis animais cada e que foram sacrificados no 7°, 14° e 21° dias após a operação, respectivamente. Foi colhido sangue para análise bioquímica e um fragmento de tecido hepático do lobo médio para estudo histológico. RESULTADOS: Tanto em relação à analise bioquímica (BT, aspartate and alanine aminotransferase AST, ALT e FAL) quanto em relação às alterações histopatológicas (fibrose, inflamação portal, inflamação parenquimatosa, alterações hepatocíticas e proliferação de ducto), não houve diferença estatística entre os grupos submetido a obstrução biliar extra-hepática sem (OBE) e com tratamento com glutamina (G). CONCLUSÃO: A suplementação com glutamina não alterou o prognóstico em relação às enzimas hepáticas e alterações histopatológicas nos animais submetidos à obstrução biliar extra-hepática.

Small cell carcinoma of the extrahepatic bile duct diagnosed with EUS-FNA and effectively treated with chemoradiation.

Small cell carcinoma of the bile duct system is extremely rare, and surgical procedures have been complicated by early hematogenous dissemination. In this study, we report a patient with small cell carcinoma of the bile duct system presenting with jaundice. The diagnosis was made early by endoscopic ultrasonography-guided fine needle aspiration biopsy (EUS-FNA). We performed radiation therapy of a total of 30 Gy, resulting in a marked decrease of serum neuron specific enolase levels and amelioration of jaundice, which had been resistant to drainage procedures. The patient was then treated with combined chemotherapy of cisplatin and CPT-11, which resulted in the disappearance of the tumor mass by image tests.

Chemoradiation may prolong survival of patients with non-bulky unresectable extrahepatic biliary carcinoma. A retrospective analysis.

PURPOSE: . This study compared stenting and chemoradiation (CRT) and attempted to identify factors that are predictive of response to CRT. MATERIAL AND METHODS: . A retrospective analysis identified 98 patients treated. The primary tumor and lymphatics received 45 Gy of three-dimensional conformal radiotherapy. Tumors were boosted to a median total dose of 50.8 Gy. Simultaneous chemotherapy was 5-fluorouracil- (5-FU) and gemcitabine-based. RTOG/NCI-CTC toxicity criteria were applied. RESULTS: . Median survival time was 11.8 months for all patients, 9.3 months for patients with stenting alone and 16.5 months with CRT (p = 0.22). Only tumor diameter was predictive of survival for treatment with CRT. A threshold of 40 mm at diagnosis distinguished two survival profiles (21.4 vs. 8.7 months; p = 0.01). Toxicity was lower for 5-FU-based CRT compared to gemcitabinebased CRT, but a safe schedule for gemcitabine-based CRT was identified. Two patients (2/25) with unresectable tumors at diagnosis had pathohistological complete response at resection after CRT. CONCLUSION: . Inclusion criteria for future CRT trials should be based on tumor size at diagnosis: patients otherwise eligible for CRT should only be included with an inoperable tumor

Delta-aminolevulinic acid transport in cancer cells of the human extrahepatic biliary duct.

This study was performed to characterize the transport of the endogenous photosensitizer delta-aminolevulinic acid in tumor cells of the extrahepatic biliary duct. Uptake of [(3)H]delta-aminolevulinic acid into human cholangiocarcinoma SK-ChA-1 cells was linear for up to 10 min, independent of a Na(+) gradient, but stimulated 3- to 4-fold by an inwardly directed H(+) gradient. Uptake of delta-aminolevulinic acid was mediated by a single transport system with an apparent affinity (K(t)) of 2.1 mM and a maximal velocity (V(max)) of 60.1 nmol. 10 min(-1). mg of protein(-1). Glycylsarcosine, alanylalanine, and cefadroxil strongly inhibited the [(3)H]delta-aminolevulinic acid uptake with K(i) values of 1.3, 0.2, and 3.6 mM, respectively. In contrast, gamma-aminobutyric acid, glycine, L-glutamic acid, and L-aspartic acid (all 10 mM) had no effect on the total [(3)H]delta-aminolevulinic acid uptake, neither at pH 6.0 nor at pH 7.5. Applying a Dixon type of experiment and the ABC test revealed that glycylsarcosine and delta-aminolevulinic acid are transported via the same system, PEPT1. Treatment of the cells with phorbol 12-myristate 13-acetate, a phorbol ester that activates protein kinase C, resulted in a significant inhibition of the transport rate. This inhibition could be blocked by cotreatment with staurosporine. We conclude that delta-aminolevulinic acid is transported by the H(+)/peptide cotransporter PEPT1 into epithelial cells of the extrahepatic biliary duct. delta-Aminolevulinic acid can be accumulated specifically in bile duct tumor cells before photodynamic therapy.

Ethanol injection therapy of an isolated bile duct associated with a biliary-cutaneous fistula.

Bile leakage after hepatic resection often results in the formation of a biliary-cutaneous fistula. Such a fistula, when caused by an isolated bile duct in the remnant liver, can be intractable. We report a successful case of ethanol injection therapy of an isolated bile duct. A 73-year-old man underwent right hepatic resection for hepatocellular carcinoma. Bile leakage occurred after surgery, and the patient developed a biliary-cutaneous fistula. Fistulography revealed an isolated bile duct in the remnant portion of the caudate lobe without communication to the main biliary system. As conservative management with simple drainage was ineffective, injection therapy with ethanol was performed with a balloon occlusion catheter. After 11 therapy sessions, the bile duct was eradicated, and the biliary- cutaneous fistula was completely healed. The post-treatment course was uneventful. Ethanol injection therapy can be a choice for management of patients with a biliary fistula caused by an isolated bile duct.

Clinical efficacy of brachytherapy combined with external-beam radiotherapy and repeated arterial infusion chemotherapy in patients with unresectable extrahepatic bile duct cancer.

The objective of this study was to evaluate the clinical efficacy of brachytherapy combined with external-beam radiotherapy and repeated arterial infusion chemotherapy in improving stent patency and prognosis in patients with unresectable bile duct cancer as compared with brachytherapy alone. Seventeen patients were treated. Five patients received brachytherapy alone before stent placement. Twelve patients received brachytherapy combined with external-beam radiotherapy (n=5), repeated hepatic arterial infusion chemotherapy using an implanted catheter and port (n=1), or both (n=6). Mean survival was significantly improved in the group that received combined therapy as compared with the group that received brachytherapy alone (16.2 months vs. 4.6 months, p<0.01). Although stent occlusion rates were similar in the two groups (42% vs. 40%), there was a trend towards longer stent patency in the combined therapy group than in the brachytherapy group (22 months vs. 3.6 months, p<0.2). Radiation gastritis necessitating gastrectomy developed in 1 patient who received external-beam radiotherapy at more than 50 Gy. Brachytherapy combined with external-beam radiotherapy and repeated hepatic arterial infusion chemotherapy increases survival compared with brachytherapy alone in patients with unresectable bile duct cancer.

Photodynamic therapy in the biliary tract.

Biliary tract cancers are rare malignancies usually characterized by slow growth and a low propensity for metastasis. Despite the relatively localized nature of these cancers, the only therapeutic measure with curative potential to date is surgical intervention. Because symptoms occur late, the diagnosis is rarely made at an early stage, and therefore only about half of the patients can have curative surgery. Patients with advanced disease face a dismal prognosis because palliative treatment options are limited. This review outlines recent advances in treatment of biliary cancer. Encouraging results from prospective, single-arm phase II trials of photodynamic therapy in nonresectable cholangiocarcinoma suggest considerable promise for this new palliative treatment modality. However, the apparent benefit of photodynamic therapy on survival, jaundice, and quality of life must be confirmed in a randomized multicenter trial.

[Caustic sclerosing cholangitis following injection of anthelmintics into rat bile duct. An experimental study]. / Kaustichen sklerozirasht kholangit sled inzhektirane v biliarnite p'tishta na pl'khove na izpolzvani v klinichnata praktika skolitsidni agenti. Eksperimentalni prouchvaniia.

It is the purpose of the study to assay the effect of intrabiliary injection of scolicide agents most frequently used in clinical practice. Fifty-five albino rats are divided up into 4 groups according to type of solution injected, as follows: control group A--with physiological saline, B--20 per cent natrium chloratum, C--10 per cent povidone iodine, and D--3 per cent hydrogenium hyperoxidatum. Histological assessment of extrahepatic bile ducts and liver parenchyma are conducted at 10 and 90 days of treatment. Lesions along with cholestatic and reparative changes are documented, most markedly expressed after injecting 20 per cent NaCl, rather weakly--after 10 per cent povidone iodine, and least pronpunced after injecting 3 per cent hydrogen peroxide. Periductal sclerosis is noted in three rats only injected with hypertonic saline. The experimental results are analyzed, and clinically relevant inferences reached.

Blood pressure reflexes following activation of capsaicin-sensitive afferent neurones in the biliopancreatic duct of rats.

1. Inflammatory diseases of the pancreas or diseases which cause obstruction within the biliary or within the biliary or pancreatic duct system are associated with severe pain. Although neuropeptides such as substance P are present in the biliary tree, only few capsaicin-sensitive, substance P-positive nerve fibres have been found in the ducts. In order to obtain functional evidence whether capsaicin-sensitive afferent neurones transmit nociceptive information arising from the biliopancreatic duct, blood pressure reflexes following electrical stimulation of the duct or increases in intraductal pressure were determined in barbiturate-anaesthetized rats. 2. Electrical stimulation of neurones in the biliopancreatic duct was carried out at 30 V, 3 ms, 50 Hz for 20s. In untreated animals the electrical stimulation resulted in rises in blood pressure by up to 25 mmHg, but in about a quarter of all animals tested this response was absent. Following the administration of phentolamine (7 mumol kg-1, i.p.) the blood pressure responses were changed to pronounced and reproducible depressor reflexes of -5 to -30 mmHg. Retrograde injections into the biliopancreatic duct of 300 microliters of a 154 mM sodium chloride solution produced increases in intraductal pressure of approximately 10 mmHg. This elicited shortlasting falls in blood pressure of 3-15 mmHg. Phentolamine significantly augmented the fall in blood pressure to 8-30 mmHg. 3. The depressor reflexes observed in both models after the administration of phentolamine were abolished by morphine (1 mumol kg-1, i.v.). The inhibition by morphine was reversed by naloxone (3 mumol kg-1, i.v.). Naloxone given before morphine did not affect the depressor reflex but prevented the inhibitory action of subsequently injected morphine.4. Acute s.c. injection of capsaicin (30 mg kg-1) abolished the depressor reflexes in response to both types of nociceptive stimulation in phentolamine-treated rats. The initial pressor effects of electrical stimulation were only partly inhibited by capsaicin whereas the basal depressor reflexes in response to elevation of intraductal pressure were abolished. In rats which had received capsaicin on the day before the experiment or had been treated with capsaicin as neonates, only minor rises in blood pressure were induced by electrical stimulation at the beginning of the experiment and no changes in blood pressure occurred after the administration of phentolamine. After adult or neonatal pretreatment with capsaicin the depressor reflexes in response to increased intraductal pressure were only small and were unchanged by phentolamine.5. The depressor reflexes following either electrical stimulation or increases in intraductal pressure were abolished by the unselective Beta-blocker, (-)-propranolol (3 micromol kg-1, i.p.), and greatly reduced by the Beta 1-blocker, metoprolol (6 micromol kg- 1, i.p.). The Beta2-preferring adrenoceptor antagonist, butoxamine(3 micromol kg-1, i.p.), had no effect on the depressor responses. The reflex falls in blood pressure were also abolished by hexamethonium (10 micromol kg-1, i.p.) but not by atropine (3 micromol kg-1, i.p.).6. Both models of stimulation of nociceptive afferents caused identical patterns of blood pressure responses following adrenalectomy or chemical sympathectomy. In adrenalectomized rats, the initial responses consisted of depressor reflexes which were not augmented but significantly reduced by phentolamine and further inhibited by metoprolol. In rats that had been pretreated with 6-hydroxydopamine(total dose 0.6 mmol kg-1) to accomplish chemical sympathectomy, nociceptive stimulation caused rises in blood pressure. Phentolamine treatment abolished these pressor effects but revealed only minor, if any, depressor responses that were unaffected by metoprolol.7. In summary, the hypotensive effects in both models constitute nociceptive reflexes since they are abolished by morphine and restored by naloxone. The afferent part of the reflex is mediated by nerve fibres sensitive to capsaicin. Both experimental procedures seem to elicit two, presumably separate, reflex mechanisms. Firstly, catecholamines released from the adrenal medulla elevate blood pressure or limit hypotensive responses via activation of vascular alpha receptors. Secondly, the reflex inhibition of the sympathetic nerve activity in the heart and the vasculature causes the nociceptive depressor reflexes.