RESUMO
PURPOSE: Perineural invasion (PN) is often found in perihilar cholangiocarcinoma. New procedure was developed to assess PN around the right hepatic artery (RHA) using dual-energy computed tomography (DECT). METHODS: Thirty patients with perihilar cholangiocarcinoma who underwent DECT before biliary drainage were retrospectively reviewed. Mask images, i.e., the periarterial layer (PAL) around the RHA and superior mesenteric artery (SMA), were made from late arterial phase DECT. The mean CT number of the PAL was measured. RESULTS: Twenty patients with PN around the RHA were classified into the PN (+) group. The remaining 10 patients without PN and other 26 patients with other diseases that are never accompanied with PN were classified into the PN (-) group. The PAL ratio (the CT number of the PAL around the RHA relative to that around the SMA) was calculated. Both the mean CT number of the PAL around the RHA and the PAL ratio were significantly higher in the PN (+) group than in the PN (-) group. According to an ROC analysis, the predictive ability of the PAL ratio was superior. Using the cutoff value of the PAL ratio 1.009, a diagnosis of PN around the RHA was made with approximately 75% accuracy. CONCLUSIONS: Assessment with CT number of the PAL reconstructed from DECT images is an easy and objective method to diagnose PN.
Assuntos
Tumor de Klatskin/patologia , Nervos Periféricos/patologia , Neoplasias do Sistema Nervoso Periférico/patologia , Idoso , Feminino , Artéria Hepática/diagnóstico por imagem , Artéria Hepática/inervação , Artéria Hepática/patologia , Humanos , Tumor de Klatskin/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Multidetectores , Invasividade Neoplásica , Nervos Periféricos/diagnóstico por imagem , Neoplasias do Sistema Nervoso Periférico/diagnóstico por imagem , Estudos RetrospectivosRESUMO
BACKGROUND: We have previously shown that sympathetic ganglia stimulation via the renal vein rapidly increases blood pressure. This study further investigated the optimal target sites and effective energy levels for stimulation of the renal vasculatures and nearby sympathetic ganglia for rapid increase in blood pressure. METHODS: The pre-study protocol for endovascular stimulations included 2 minutes of stimulation (1-150 V and 10 pulses per second) and at least 2 minutes of rest during poststimulation. If blood pressure and/or heart rate were changed during the stimulation, time to return to baseline was allowed prior to the next stimulation. RESULTS: In 11 acute canine studies, we performed 85 renal artery, 30 renal vein, and 8 hepatic vasculature stimulations. The mean arterial pressure (MAP) rapidly increased during stimulation of renal artery (95 ± 18 mmHg vs. 103 ± 15 mmHg; P < 0.0001), renal vein (90 ± 16 mmHg vs. 102 ± 20 mmHg; P = 0.001), and hepatic vasculatures (74 ± 8 mmHg vs. 82 ± 11 mmHg; P = 0.04). Predictors of a significant increase in MAP were energy >10 V focused on the left renal artery, bilateral renal arteries, and bilateral renal veins (especially the mid segment). Overall, heart rate was unchanged, but muscle fasciculation was observed in 22.0% with an output >10 V (range 15-150 V). Analysis after excluding the stimulations that resulted in fasciculation yielded similar results to the main findings. CONCLUSIONS: Stimulation of intra-abdominal vasculatures promptly increased the MAP and thus may be a potential treatment option for hypotension in autonomic disorders. Predictors of optimal stimulation include energy delivery and the site of stimulation (for the renal vasculatures), which informs the design of subsequent research.
Assuntos
Pressão Arterial , Doenças do Sistema Nervoso Autônomo/terapia , Terapia por Estimulação Elétrica/métodos , Procedimentos Endovasculares/métodos , Gânglios Simpáticos/fisiopatologia , Hipotensão Ortostática/terapia , Vasodilatação , Animais , Doenças do Sistema Nervoso Autônomo/diagnóstico , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Artéria Celíaca/inervação , Cães , Terapia por Estimulação Elétrica/instrumentação , Procedimentos Endovasculares/instrumentação , Frequência Cardíaca , Artéria Hepática/inervação , Veias Hepáticas/inervação , Hipotensão Ortostática/diagnóstico , Hipotensão Ortostática/fisiopatologia , Masculino , Artéria Renal/inervação , Veias Renais/inervação , Fatores de Tempo , Dispositivos de Acesso VascularRESUMO
This study quantified the distribution of nerves and adjacent anatomies surrounding human common hepatic artery (CHA) as guidance for catheter based denervation. CHA collected from cadaveric human donors (n = 20) were histologically evaluated and periarterial dimensions and distributions of nerves, lymph nodes, pancreas and blood vessels quantified by digital morphometry. Nerve abundance decreased significantly with distance from the aortic ostium (P < 0.0001) and was higher in the Superior/Inferior compared to the Anterior/Posterior quadrants (P = 0.014). In each locational group, nerves were absent from the artery wall, and starting 0.5-1.0 mm from the lumen exhibited a first order dependence on radial distance, fully defined by the median distance. Median subject-averaged nerve distance to the lumen was 2.75 mm, ranging from 2.1-3.1 mm in different arterial segments and quadrants and 2.0-3.5 mm in individuals. Inter-individual variance was high, with certain individuals exhibiting 50th and 75th nerve distances of, respectively, 3.5 and 6.5 mm The pancreas rarely approached within 4 mm of the lumen proximally and 2.5 mm more distally. The data indicate that the CHA is a rich and accessible target for sympathetic denervation regardless of sex and diabetes, with efficacy and safety most optimally balanced proximally.
Assuntos
Artéria Hepática/inervação , Fígado/inervação , Linfonodos/inervação , Pâncreas/inervação , Simpatectomia/métodos , Idoso , Autopsia , Vasos Sanguíneos , Ablação por Cateter/métodos , Feminino , Artéria Hepática/anatomia & histologia , Humanos , Fígado/anatomia & histologia , Fígado/irrigação sanguínea , Circulação Hepática/fisiologia , Linfonodos/anatomia & histologia , Linfonodos/irrigação sanguínea , Masculino , Pâncreas/anatomia & histologia , Pâncreas/irrigação sanguínea , Sistema Nervoso SimpáticoRESUMO
The objective of this study was to assess the safety of surgical common hepatic artery denervation (CHADN). This procedure has previously been shown to improve glucose tolerance in dogs fed a high-fat high-fructose (HFHF) diet. We assessed the hypoglycemic response of dogs by infusing insulin at a constant rate (1.5 mU/kg/min) for 3 h and monitoring glucose and the counterregulatory hormones (glucagon, catecholamine, and cortisol). After an initial hypoglycemic study, the dogs were randomly assigned to a SHAM surgery (n = 4) or hepatic sympathetic denervation (CHADN, n = 5) and three follow-up studies were performed every month up to 3 months after the surgery. The level of norepinephrine (NE) in the liver and the pancreas was significantly reduced in the CHADN dogs, showing a decrease in sympathetic tone to the splanchnic organs. There was no evidence of any defect of the response to hypoglycemia after the CHADN surgery. Indeed, the extent of hypoglycemia was similar in the SHAM and CHADN groups (~45 mg/dl) for the same amount of circulating insulin (~50 µU/ml) regardless of time or surgery. Moreover the responses of the counterregulatory hormones were similar in extent and pattern during the 3 h of hypoglycemic challenge. Circulating lactate, glycerol, free fatty acids, and beta-hydroxybutyrate were also unaffected by CHADN during fasting conditions or during the hypoglycemia. There were no other notable surgery-induced changes over time in nutrients, minerals, and hormones clinically measured in the dogs nor in the blood pressure and heart rate of the animals. The data suggest that the ablation of the sympathetic nerve connected to the splanchnic bed is not required for a normal counterregulatory response to insulin-induced hypoglycemia and that CHADN could be a safe new therapeutic intervention to improve glycemic control in individuals with metabolic syndrome or type 2 diabetes.
Assuntos
Artéria Hepática/inervação , Artéria Hepática/cirurgia , Resistência à Insulina , Animais , Denervação/métodos , Modelos Animais de Doenças , Cães , Técnica Clamp de Glucose , Intolerância à Glucose , Hiperglicemia , MasculinoRESUMO
BACKGROUND: Cardiovascular and metabolic regulation is governed by neurohumoral signalling in relevant organs such as kidney, liver, pancreas, duodenum, adipose tissue, and skeletal muscle. Combined targeting of relevant neural outflows may provide a unique therapeutic opportunity for cardiometabolic disease. OBJECTIVES: We aimed to investigate the feasibility, safety, and performance of a novel device-based approach for multi-organ denervation in a swine model over 30 and 90 days of follow-up. METHODS: Five Yorkshire cross pigs underwent combined percutaneous denervation in the renal arteries and the common hepatic artery (CHA) with the iRF Denervation System. Control animals (n = 3) were also studied. Specific energy doses were administered in the renal arteries and CHA. Blood was collected at 30 and 90 days. All animals had a pre-terminal procedure angiography. Tissue samples were collected for norepinephrine (NEPI) bioanalysis. Histopathological evaluation of collateral structures and tissues near the treatment sites was performed to assess treatment safety. RESULTS: All animals entered and exited the study in good health. No stenosis or vessel abnormalities were present. No significant changes in serum chemistry occurred. NEPI concentrations were significantly reduced in the liver (- 88%, p = 0.005), kidneys (- 78%, p < 0.001), pancreas (- 78%, p = 0.018) and duodenum (- 95%, p = 0.028) following multi-organ denervation treatment compared to control animals. Histologic findings were consistent with favourable tissue responses at 90 days follow-up. CONCLUSIONS: Significant and sustained denervation of the treated organs was achieved at 90 days without major safety events. Our findings demonstrate the feasibility of multi-organ denervation using a novel iRF Denervation System in a single procedure.
Assuntos
Artéria Hepática/cirurgia , Artéria Renal/cirurgia , Simpatectomia/métodos , Angiografia , Animais , Fatores de Risco Cardiometabólico , Modelos Animais de Doenças , Estudos de Viabilidade , Seguimentos , Artéria Hepática/inervação , Humanos , Norepinefrina/metabolismo , Artéria Renal/inervação , Suínos , Simpatectomia/efeitos adversos , Fatores de TempoRESUMO
Comparative studying, using histological and biomicroscopic methods, of the dosed cryohepatodestruction (CHD), periarterial cryodenervation of hepatic artery (CDHA) and their concomitant application influence on the dynamics of hepatic restoration processes in experimental cirrhosis was performed. The investigations were done on 215 male rats owing body mass 200-280 g in a not changed and pathologically changed liver. There was shown, that CDHA promotes changes in hepatic tissue microhemocirculation, as well as the enhancement of the sinusoidal vessels diameter and relative square of vascular bed. CHD stimulates the reparative processes course in a pathologically changed organ. There was established, that while simultaneous application of two cryosurgical methods, the velocity and grade of restoration processes in cirrhotically-changed liver are enhanced in comparison with such indices changes while separate usage of these two methods.
Assuntos
Criocirurgia/métodos , Cirrose Hepática Experimental/cirurgia , Fígado/cirurgia , Animais , Denervação , Artéria Hepática/inervação , Artéria Hepática/cirurgia , Artéria Hepática/ultraestrutura , Fígado/irrigação sanguínea , Fígado/inervação , Fígado/ultraestrutura , Circulação Hepática , Cirrose Hepática Experimental/patologia , Masculino , Microvasos/inervação , Microvasos/cirurgia , Microvasos/ultraestrutura , Ratos , Resultado do TratamentoRESUMO
This study assessed the effectiveness of surgical sympathetic denervation of the common hepatic artery (CHADN) in improving glucose tolerance. CHADN eliminated norepinephrine content in the liver and partially decreased it in the pancreas and the upper gut. We assessed oral glucose tolerance at baseline and after 4 weeks of high-fat high-fructose (HFHF) feeding. Dogs were then randomized to sham surgery (SHAM) (n = 9) or CHADN surgery (n = 11) and retested 2.5 or 3.5 weeks later while still on the HFHF diet. CHADN improved glucose tolerance by â¼60% in part because of enhanced insulin secretion, as indicated by an increase in the insulinogenic index. In a subset of dogs (SHAM, n = 5; CHADN, n = 6), a hyperinsulinemic-hyperglycemic clamp was used to assess whether CHADN could improve hepatic glucose metabolism independent of a change in insulin release. CHADN reduced the diet-induced defect in net hepatic glucose balance by 37%. In another subset of dogs (SHAM, n = 4; CHADN, n = 5) the HFHF diet was continued for 3 months postsurgery and the improvement in glucose tolerance caused by CHADN continued. In conclusion, CHADN has the potential to enhance postprandial glucose clearance in states of diet-induced glucose intolerance.
Assuntos
Dieta Hiperlipídica , Açúcares da Dieta , Intolerância à Glucose/metabolismo , Artéria Hepática/inervação , Fígado/metabolismo , Norepinefrina/metabolismo , Simpatectomia , Animais , Cães , Frutose , Técnica Clamp de Glucose , Teste de Tolerância a Glucose , Masculino , Pâncreas/metabolismo , Distribuição Aleatória , Trato Gastrointestinal Superior/metabolismoRESUMO
It is known that acute spinal cord injury (SCI) produces hemodynamic alterations, including a reduction in liver blood flow that is more pronounced after high-thoracic than after low-thoracic injury. To determine if these changes have an impact in the pharmacokinetics of high extraction drugs (i.e., those drugs which clearance mainly depends on liver blood flow), we studied the pharmacokinetics of a model compound, phenacetin, and of its main metabolite, acetaminophen, in rats 24 h after a high (T1) or a low (T8) SCI, as well as in sham-lesioned controls. After intravenous administration to animals with SCI, reductions in drug clearance and distribution led to an increase in blood concentrations. These alterations were more pronounced after high than after low SCI, as expected from hemodynamic changes. After oral administration, phenacetin blood levels were similar in sham-lesioned and T1-injured animals, but decreased by injury at T8. This is likely due to a reduction in drug absorption which compensates the changes in distribution and elimination induced by injury at T1, whereas it prevails in T8-lesioned animals. Acetaminophen blood concentrations observed after intravenous or oral phenacetin, or after the oral administration of acetaminophen by itself, were increased or reduced, depending on the overall effect of the alterations on absorption, first pass metabolism, distribution and elimination induced by high and low SCI. Results demonstrate that acute SCI significantly alters the pharmacokinetics of high extraction drugs. The outcome of such alterations depends on the level of SCI and on the route of administration.
Assuntos
Acetaminofen/farmacocinética , Fígado/irrigação sanguínea , Fígado/fisiopatologia , Fenacetina/farmacocinética , Fluxo Sanguíneo Regional/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Acetaminofen/metabolismo , Administração Oral , Animais , Denervação , Modelos Animais de Doenças , Feminino , Artéria Hepática/inervação , Artéria Hepática/fisiopatologia , Injeções Intravenosas , Fígado/metabolismo , Taxa de Depuração Metabólica/fisiologia , Fenacetina/metabolismo , Ratos , Ratos Sprague-Dawley , Vértebras Torácicas , Fatores de TempoRESUMO
Although Delta(9)-tetrahydrocannabinol (THC) produces analgesia, its effects on nociceptive primary afferents are unknown. These neurons participate not only in pain signaling but also in the local response to tissue injury. Here, we show that THC and cannabinol induce a CB(1)/CB(2) cannabinoid receptor-independent release of calcitonin gene-related peptide from capsaicin-sensitive perivascular sensory nerves. Other psychotropic cannabinoids cannot mimic this action. The vanilloid receptor antagonist ruthenium red abolishes the responses to THC and cannabinol. However, the effect of THC on sensory nerves is intact in vanilloid receptor subtype 1 gene knock-out mice. The THC response depends on extracellular calcium but does not involve known voltage-operated calcium channels, glutamate receptors, or protein kinases A and C. These results may indicate the presence of a novel cannabinoid receptor/ion channel in the pain pathway.
Assuntos
Vias Aferentes/efeitos dos fármacos , Canabinol/farmacologia , Dronabinol/farmacologia , Receptor CB2 de Canabinoide , Receptores de Droga/efeitos dos fármacos , Vias Aferentes/fisiologia , Animais , Bioensaio , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Cálcio/metabolismo , Canabinoides/farmacologia , Capsaicina/farmacologia , Relação Dose-Resposta a Droga , Feminino , Artéria Hepática/efeitos dos fármacos , Artéria Hepática/inervação , Artéria Hepática/fisiologia , Técnicas In Vitro , Masculino , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/inervação , Artérias Mesentéricas/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/fisiologia , Dor , Psicotrópicos/farmacologia , Ratos , Ratos Wistar , Receptores de Canabinoides , Receptores de Droga/antagonistas & inibidores , Receptores de Droga/deficiência , Receptores de Droga/metabolismo , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologiaRESUMO
BACKGROUND: In a recent study, disturbances of hepatic microcirculation at harvesting caused by in situ organ manipulation dramatically reduced survival after a liver transplant. Because hepatic innervation is involved in the regulation of liver hemodynamics, the effect of denervation before harvesting was assessed here. METHODS: The livers were harvested from female Lewis rats (200-230 g) within 25 min. Briefly, after minimal dissection during the first 12 min, the livers were either manipulated gently or left alone for 13 min. Subsequently, an orthotopic liver transplant was performed after 1 hr of storage in cold UW solution. Some donors livers underwent microsurgical denervation before harvesting or rats were given hexamethonium (10 mg/kg, i.v.), a ganglionic blocking agent. RESULTS: In the nonmanipulated group, survival was 100% after the transplant; however, gentle manipulation decreased survival by about 50%. Furthermore, manipulation elevated serum transaminases and bilirubin 6- to 8-fold 8 hr after the transplant and caused necrosis of about 25% of hepatocytes. After organ harvesting, the rate of entry and exit of fluorescein dextran, a dye confined to the vascular space, was decreased 2- to 4-fold, and the maximal increase of surface fluorescence was blunted about 2-fold. Pimonidazole binding, which reflects tissue hypoxia, was increased 2-fold by manipulation. Denervation of the liver before organ harvesting or treatment with hexamethonium prevented the effects of organ manipulation on all parameters studied. CONCLUSION: These data indicate for the first time that hepatic denervation before organ harvesting prevents detrimental effects of brief, gentle manipulation of the liver during harvesting on survival after the transplant. This is consistent with the hypothesis that organ manipulation disturbs the hepatic microcirculation and causes hypoxia at harvesting using mechanisms dependent on innervation.
Assuntos
Artéria Hepática/inervação , Transplante de Fígado/imunologia , Fígado/irrigação sanguínea , Obtenção de Tecidos e Órgãos , Animais , Anti-Hipertensivos/farmacologia , Denervação , Feminino , Sobrevivência de Enxerto , Hexametônio/farmacologia , Hipóxia/fisiopatologia , Hipóxia/prevenção & controle , Microcirculação , Nitroimidazóis/metabolismo , Radiossensibilizantes/metabolismo , Ratos , Ratos Endogâmicos Lew , Traumatismo por Reperfusão/etiologiaRESUMO
1. Transmural electrical field stimulation produced a transient contraction of the isolated hepatic artery of the rabbit that was frequency-dependent up to 64 Hz. A contraction was rarely evoked at a stimulation frequency of less than 8 Hz and never at 4 Hz or less. All contractions were abolished in the presence of tetrodotoxin. 2. Neurogenic contractions were partially inhibited by prazosin. After desensitization of the P2X-purinoceptor with alpha, beta-methylene ATP, contractions in response to electrical stimulation were significantly reduced at all frequencies tested (4-64 Hz). In most cases, contractions were abolished by a combination of both drugs. 3. In vessels treated with 6-hydroxydopamine, no nerve-mediated contractile responses were observed. 4. In arteries from reserpine-treated rabbits, nerve stimulation evoked contractions that were resistant to prazosin. After desentization of the P2X-purinoceptor with alpha,beta-methylene ATP, no neurogenic contractile response remained. 5. The tissue contracted to exogenously applied noradrenaline and alpha,beta-methylene ATP. There was an increase in sensitivity to noradrenaline in 6-hydroxydopamine-treated vessels compared with control vessels, but no difference in potency to alpha,beta-methylene ATP was detected. The potency of noradrenaline and alpha,beta-methylene ATP was not significantly affected by reserpine treatment. 6. In control tissues, fluorescence histochemistry demonstrated the presence of noradrenergic nerve fibres. Noradrenaline-containing nerves were not observed in 6-hydroxydopamine-treated or reserpine-treated vessels. 7. It is concluded that noradrenaline and ATP are cotransmitters in the sympathetic nerves supplying the hepatic artery of the rabbit. In contrast to other vessels, the hepatic artery requires a relatively high frequency of stimulation to evoke contractions and the purinergic component is not frequency-dependent. The significance of this finding in terms of the physiological demands of blood flow to the liver are discussed.
Assuntos
Músculo Liso Vascular/inervação , Neurotransmissores , Norepinefrina/fisiologia , Purinas/metabolismo , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/farmacologia , Trifosfato de Adenosina/fisiologia , Animais , Catecolaminas/metabolismo , Estimulação Elétrica , Artéria Hepática/inervação , Artéria Hepática/fisiologia , Histocitoquímica , Hidroxidopaminas/farmacologia , Técnicas In Vitro , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso Vascular/fisiologia , Oxidopamina , Prazosina/farmacologia , Coelhos , Reserpina/farmacologiaRESUMO
In the presence of ouabain (1 mM), acetylcholine and KCl (5 mM) evoked endothelium-independent relaxations in rat hepatic arteries. Treatment with capsaicin (10 microM), scopolamine (1 microM) or CGRP(8 - 37) (3 microM) prevented these relaxations. Acetylcholine-induced relaxations in intact arterial segments in the presence of indomethacin (10 microM) and N(G)-nitro-L-arginine (0.3 mM) were only partially inhibited by ouabain plus BaCl(2) (30 microM). However, ouabain plus BaCl(2) almost abolished such relaxations in capsaicin-pre-treated preparations. In arteries without endothelium, the neurosecretagogue alpha-latrotoxin (1 nM) induced complete relaxations, which were abolished by CGRP(8 - 37) or pre-treatment with capsaicin. alpha-Latrotoxin also induced a smooth muscle hyperpolarization (12+/-2 mV), which was abolished by CGRP(8 - 37). The ability of ouabain to disclose a CGRP-mediated neurogenic relaxation must be considered when this agent is used as a pharmacological tool. The results further suggest that CGRP is a nerve-derived hyperpolarizing factor in the rat hepatic artery.
Assuntos
Acetilcolina/farmacologia , Cardiotônicos/farmacologia , Artéria Hepática/efeitos dos fármacos , Neurônios Aferentes/efeitos dos fármacos , Ouabaína/farmacologia , Cloreto de Potássio/farmacologia , Vasodilatadores/farmacologia , Animais , Fatores Biológicos/fisiologia , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Feminino , Artéria Hepática/inervação , Neurônios Aferentes/fisiologia , Ratos , Ratos Wistar , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologiaRESUMO
1 The sympathetically-innervated hepatic arterial vascular bed of the dog was perfused from a femoral artery. Hepatic arterial blood flow and perfusion pressure were recorded continuously, and the hepatic arterial vascular resistance (HAVR) calculated from these measurements.2 Intra-arterial injections of phenylephrine caused dose-dependent rises in HAVR, indicating hepatic arterial vasoconstriction, at all doses above threshold. No secondary reductions in HAVR followed these responses.3 Intra-arterial injections of isoprenaline caused only dose-dependent reductions in HAVR at doses above threshold.4 Intra-arterial injections of noradrenaline typically caused an initial increase in HAVR which was followed at all but the highest doses by a secondary, delayed, reduction in HAVR.5 Intra-arterial injections of adrenaline, like those of noradrenaline, resulted in hepatic arterial vasoconstriction followed by hepatic arterial vasodilatation.6 On a molar basis, the most potent hepatic arterial vasoconstrictor was noradrenaline, followed by adrenaline and phenylephrine.7 The maximum reductions in HAVR caused by adrenaline (mean reduction = 21.9%) and noradrenaline (16.9%) were significantly smaller than those due to isoprenaline ((P) < 0.001).8 Propranolol attenuated the hepatic arterial vasodilator responses due to isoprenaline, and the secondary falls in HAVR following intra-arterial adrenaline and noradrenaline.9 Propranolol did not modify the vasoconstrictor responses to phenylephrine.10 Both adrenaline and noradrenaline were more potent hepatic arterial vasoconstrictors after propranolol than in the absence of beta-adrenoceptor blockade. The potentiation of the vasoconstrictor effects of adrenaline was statistically significant.11 After propranolol, adrenaline was a more potent hepatic arterial vasoconstrictor than noradrenaline.12 Since the beta-adrenoceptors in the hepatic arterial vasculature were not blocked by atenolol, but were stimulated by salbutamol, it is concluded that they are predominantly of the beta(2)-type.13 The vasoconstrictor actions of phenylephrine, noradrenaline and adrenaline were all antagonized by the systemic administration of phentolamine, all three dose-response curves being shifted to the right.14 The results are discussed with regard to the possible control of the hepatic arterial vasculature by naturally-occurring catecholamines.
Assuntos
Epinefrina/farmacologia , Isoproterenol/farmacologia , Circulação Hepática/efeitos dos fármacos , Norepinefrina/farmacologia , Fenilefrina/farmacologia , Receptores Adrenérgicos beta/fisiologia , Receptores Adrenérgicos/fisiologia , Albuterol/farmacologia , Animais , Atenolol/farmacologia , Cães , Relação Dose-Resposta a Droga , Interações Medicamentosas , Artéria Hepática/inervação , Propranolol/farmacologia , Receptores Adrenérgicos beta/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacosRESUMO
We studied the distribution of neuronal nitric oxide synthase (nNOS) in the rat liver with a specific polyclonal antibody by using immunocytochemical procedures in the light microscopic level. Immunoreactive varicose nerve fibers were found forming a dense plexus around the interlobular hepatic artery and the interlobular bile duct in the hepatic hilus, and in the hepatic artery ramifications of the portal triads. The density of nNOS positive nerve fibers decreases with successive portal ramifications, and some non-immune positive nerve fibers were found in the distal portions of the arterial vessels. The presence of the nNOS positive nerve fibers suggests that the possible main functional role could be related with the regulation of hepatic blood circulation and hepatobiliary activities.
Assuntos
Fígado/inervação , Fibras Nervosas/enzimologia , Neurônios/enzimologia , Óxido Nítrico Sintase/análise , Animais , Ductos Biliares Intra-Hepáticos/inervação , Artéria Hepática/inervação , Imuno-Histoquímica , Fígado/citologia , Masculino , Sistema Porta/inervação , Ratos , Ratos WistarRESUMO
The aim of the present study was to elucidate the influence of the hepatic sympathetic and parasympathetic (vagal) nerves on the hepatic blood flow (HBF), both tonically and when stimulated, using urethane-anesthetized rats as an in vivo experimental model. HBF was measured at the surface of the lateral left lobe of the liver using laser Doppler flowmetry and the hydrogen gas clearance method. Denervation of the hepatic sympathetic nerves had no influence on the HBF, while electrical stimulation of the hepatic sympathetic nerves caused the HBF to decrease in a frequency-dependent manner. This decrease was shown to occur via alpha-adrenergic receptors. In contrast, neither denervation nor electrical stimulation of the hepatic vagal nerves elicited significant changes in the HBF. These results demonstrate that the sympathetic and vagal hepatic nerves have little or no tonic influence on the HBF of rats under urethane anesthesia, whereas the HBF decreases in response to activation of the hepatic sympathetic nerves.
Assuntos
Artéria Hepática/inervação , Fígado/irrigação sanguínea , Fígado/inervação , Receptores Adrenérgicos alfa/metabolismo , Fluxo Sanguíneo Regional/fisiologia , Fibras Simpáticas Pós-Ganglionares/fisiologia , Nervo Vago/fisiologia , Antagonistas Adrenérgicos alfa/farmacologia , Anestésicos Inalatórios/farmacologia , Animais , Denervação Autônoma , Estimulação Elétrica , Artéria Hepática/efeitos dos fármacos , Artéria Hepática/fisiologia , Fluxometria por Laser-Doppler , Fígado/fisiologia , Masculino , Fentolamina/farmacologia , Ratos , Ratos Wistar , Receptores Adrenérgicos alfa/efeitos dos fármacos , Fluxo Sanguíneo Regional/efeitos dos fármacos , Fibras Simpáticas Pós-Ganglionares/efeitos dos fármacos , Uretana/farmacologiaRESUMO
Hepatic arteries are reportedly innervated by vasoconstrictor and vasodilator nerves. Experiments were carried out to investigate the possible involvement of calcitonin gene related peptide (CGRP) and nitric oxide as neurotransmitters during the relaxation of the rat common hepatic artery produced by transmural electrical field stimulation (ES). Common hepatic arteries were excised under ether-anesthesia from 6 weeks-old female rats, and isometric tensions recorded from endothelium-damaged ring preparations. In the presence of atropine and guanethidine, ES relaxed arteries which had been previously contracted with vasopressin. The relaxation response to ES was attenuated by either tetrodotoxin or capsaicin-pretreatment. CGRP induced a concentration-dependent relaxation, which was inhibited by the CGRP antagonist CGRP(8-37). The ES-induced relaxation was attenuated either slightly by the nitric oxide synthesis inhibitor L-nitroarginine (L-NNA) or markedly by CGRP(8-37). The relaxation response was nearly abolished in the presence of both CGRP(8-37) and L-NNA. These results may indicate that the nerve stimulation-induced vasodilatation of the rat common hepatic artery is mediated mainly by CGRP and partly by nitric oxide.
Assuntos
Artéria Hepática/fisiologia , Relaxamento Muscular/fisiologia , Músculo Liso Vascular/fisiologia , Acetilcolina/farmacologia , Animais , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Capsaicina/farmacologia , Estimulação Elétrica , Feminino , Artéria Hepática/efeitos dos fármacos , Artéria Hepática/inervação , Técnicas In Vitro , Contração Isométrica/efeitos dos fármacos , Contração Isométrica/fisiologia , Relaxamento Muscular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/inervação , Nitroarginina/farmacologia , Fragmentos de Peptídeos/farmacologia , Ratos , Ratos Wistar , Tetrodotoxina/farmacologia , Vasodilatação , Vasopressinas/farmacologiaRESUMO
We have characterised nerve-mediated vasodilations in small arteries of the rat hepatic mesentery. Stimulation of sympathetic nerves (10 Hz, 10 s) produced a vasodilation which was abolished by the beta-adrenoceptor antagonist, propranolol (2 x 10(-6) M), but was unaffected by NG-nitro-L-arginine methyl ester (L-NAME, 10(-5) M). Stimulation of sensory nerves produced a large vasodilation that was abolished by capsaicin (10(-6) M). This vasodilation was unaffected by L-NAME (10(-5) M), but significantly reduced by the calcitonin gene related peptide (CGRP) antagonist, CGRP8-37 (10(-6) M), or inhibition of adenylate cyclase (SQ22356, 2 x 10(-5) M; 2',5'-dideoxyadenosine, 2 x 10(-4) M). Stimulation of cholinergic nerves produced a small vasodilation which was significantly reduced by scopolamine (10(-6) M). Expression of mRNA for CGRP1 receptors, muscarinic m2, m3 and m5 receptors and neurokinin1 (NK1) and NK3, receptors was detected. Perivascular nerves were immunoreactive for CGRP and substance P. No role was found for substance P, neuronal NO, ATP or adenosine in nerve-mediated responses. L-NAME (10(-5) M) potentiated vasoconstrictions following sympathetic nerve stimulation. This effect was reversed by L-arginine (10(-3) M) and cromakalim (10(-6) M) and mimicked by glybenclamide (10(-5) M), thus implicating KATP channels. Vasodilation in response to sensory nerve stimulation was directly proportional to the level of preconstriction, while vasodilation in response to neurogenic or applied acetylcholine was inhibited at high levels of preconstriction. We hypothesize that, under conditions of intensive vasoconstriction, some endothelial-dependent vasodilations may be less important than vasodilations activated directly through the smooth muscle.
Assuntos
Arteríolas/metabolismo , Artéria Hepática/metabolismo , Fígado/irrigação sanguínea , Vasodilatação/fisiologia , Inibidores de Adenilil Ciclases , Antagonistas Adrenérgicos beta/farmacologia , Animais , Arteríolas/efeitos dos fármacos , Arteríolas/inervação , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Estimulação Elétrica , Inibidores Enzimáticos/farmacologia , Feminino , Artéria Hepática/efeitos dos fármacos , Artéria Hepática/inervação , Imuno-Histoquímica , Masculino , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/inervação , Artérias Mesentéricas/metabolismo , Antagonistas Muscarínicos/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Fragmentos de Peptídeos/farmacologia , Canais de Potássio/efeitos dos fármacos , Canais de Potássio/metabolismo , Propranolol/farmacologia , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos WKY , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/genética , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismo , Receptores Muscarínicos/genética , Receptores Muscarínicos/metabolismo , Receptores da Neurocinina-1/genética , Receptores da Neurocinina-1/metabolismo , Receptores da Neurocinina-3/genética , Receptores da Neurocinina-3/metabolismo , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacosRESUMO
Changes in hepatic hemodynamics during blood pressure oscillations caused by the side pressure exertion procedure (SPEP) were studied in anesthetized rabbits. The brain was excluded from systemic circulation except for one of the common carotids, which was compressed with stepwise elevated pressure. In normovolemia, the hepatic arterial flow (HAF) increased as the systemic arterial pressure (SAP) rose up to 140 mmHg, and then decreased as SAP rose further. With the rise of SAP, the portal venous flow (PVF) initially rose slightly, followed by a nearly constant decrease. Hemorrhaging influenced slightly the changes of HAF and PVF with the SAP rise. After volume loading, SAP and PVF markedly increased but HAF changed little. However, the initial increase in HAF with the SAP rise was markedly depressed by volume loading. PVF conspicuously decreased without initial increase with the rise in SAP. The hepatic vascular bed has a mechanism that prevents expected decrease of blood flow after hemorrhaging and during neurogenic hypertension. The interaction among HAF, PVF, and PVP may be involved in this mechanism.
Assuntos
Pressão Sanguínea , Hemodinâmica , Circulação Hepática , Sistema Vasomotor/fisiopatologia , Animais , Volume Sanguíneo , Isquemia Encefálica/fisiopatologia , Circulação Cerebrovascular , Feminino , Hemorragia/fisiopatologia , Artéria Hepática/inervação , Masculino , Veia Porta/inervação , Pressorreceptores/fisiopatologia , Coelhos , Resistência VascularRESUMO
Intrahepatic forms of cholestasis were detected in 2,9% of patients operated upon for hepatobiliary pathology. The optimum method of the surgical treatment of cholestatic forms of hepatitis and early stages of liver cirrhosis is considered to be periarterial nephrectomy of the proper hepatic artery in combination with omentohepatodia-phragmopexy which was successfully fulfilled in 50 patients.
Assuntos
Colestase Intra-Hepática/cirurgia , Denervação/métodos , Estudos de Avaliação como Assunto , Artéria Hepática/inervação , Humanos , Ligadura , Fígado/irrigação sanguínea , Nefrectomia/métodos , Omento/cirurgia , Artéria Esplênica/cirurgiaRESUMO
The author considers that the participation of surgeons in the treatment of patients with acute and chronic hepatitis may be promising. The operation for acute hepatitis is aimed at liquidation of another disease of the patients, that for chronic hepatitic is fulfilled in order to relieve severe manifestations of the disease.