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The Role of Neural Signaling in the Pancreatic Cancer Microenvironment. Cancers (Basel) 2022; 14:cancers14174269. [PMID: 36077804 PMCID: PMC9454556 DOI: 10.3390/cancers14174269] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Pancreatic cancer is a highly lethal malignant disease with a dense stroma, called the tumor microenvironment. Accumulating evidence indicates the important role of sympathetic, parasympathetic, and sensory nerves in the tumor microenvironment of various cancers, including pancreatic cancer. Cancer cells and neural cells interact with each other to form a complex network and cooperatively promote cancer growth and invasion. In this review article, we describe the current understanding of the role of nerves in the tumor microenvironment. Abstract Pancreatic cancer is one of the most lethal malignant diseases. Various cells in the tumor microenvironment interact with tumor cells and orchestrate to support tumor progression. Several kinds of nerves are found in the tumor microenvironment, and each plays an essential role in tumor biology. Recent studies have shown that sympathetic, parasympathetic, and sensory neurons are found in the pancreatic cancer microenvironment. Neural signaling not only targets neural cells, but tumor cells and immune cells via neural receptors expressed on these cells, through which tumor growth, inflammation, and anti-tumor immunity are affected. Thus, these broad-range effects of neural signaling in the pancreatic cancer microenvironment may represent novel therapeutic targets. The modulation of neural signaling may be a therapeutic strategy targeting the whole tumor microenvironment. In this review, we describe the current understanding of the role of nerves in the tumor microenvironment of various cancers, with an emphasis on pancreatic cancer. We also discuss the underlying mechanisms and the possibility of therapeutic applications.
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Ørgaard A, Holst JJ. The role of somatostatin in GLP-1-induced inhibition of glucagon secretion in mice. Diabetologia 2017; 60:1731-1739. [PMID: 28551699 PMCID: PMC5552842 DOI: 10.1007/s00125-017-4315-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 04/10/2017] [Indexed: 01/11/2023]
Abstract
AIMS/HYPOTHESIS Glucagon-like peptide-1 (GLP-1) receptor agonists are currently used for the treatment of type 2 diabetes. Their main mechanism of action is enhancement of glucose-induced insulin secretion (from increased beta cell glucose sensitivity) and inhibition of glucagon secretion. The latter has been demonstrated to account for about half of their blood glucose-lowering activity. Whereas the effect of GLP-1 on insulin secretion is clearly dependent on ambient glucose concentrations and has been described in detail, the mechanism responsible for the inhibitory effect of GLP-1 on glucagon secretion is heavily debated. Glucagon inhibition is also said to be glucose-dependent, although it is unclear what is meant by this. We hypothesise here that GLP-1 does not inhibit glucagon secretion during hypoglycaemia because the inhibition depends on somatostatin secretion, which in turn is dependent on glucose levels. METHODS We used the perfused mouse pancreas model to investigate this hypothesis. RESULTS We found that, in this model, GLP-1 was able to significantly inhibit glucagon secretion from pancreatic alpha cells at all glucose levels tested: 6.0, 1.5 and 0.5 mmol/l (-27.0%, -37.1%, and -23.6%, respectively), and the decrease in glucagon secretion was invariably accompanied by an increase in somatostatin secretion (+286.8%, +158.7%, and +118.8%, respectively). Specific blockade of somatostatin receptor 2 increased glucagon secretion (+118.8% at 1.5 mmol/l glucose and +162.9% at 6.0 mmol/l glucose) and completely eliminated the inhibitory effect of GLP-1. CONCLUSIONS/INTERPRETATION We have shown here that the glucagon-lowering effect of GLP-1 is entirely mediated through the paracrine actions of somatostatin in the perfused mouse pancreas. However, in this model, the inhibitory effect of GLP-1 was preserved at hypoglycaemic levels, leaving unanswered the question of how this is avoided in vivo in individuals treated with GLP-1 receptor agonists.
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Affiliation(s)
- Anne Ørgaard
- Novo Nordisk Foundation Center for Basic Metabolic Research, Translational Metabolic Physiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- University of Copenhagen, Department of Biomedical Sciences, Faculty of Health Sciences, Blegdamsvej 3B, Bldg 12.2, 2200, Copenhagen N, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Translational Metabolic Physiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
- University of Copenhagen, Department of Biomedical Sciences, Faculty of Health Sciences, Blegdamsvej 3B, Bldg 12.2, 2200, Copenhagen N, Denmark.
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Veedfald S, Plamboeck A, Deacon CF, Hartmann B, Knop FK, Vilsbøll T, Holst JJ. Cephalic phase secretion of insulin and other enteropancreatic hormones in humans. Am J Physiol Gastrointest Liver Physiol 2016; 310:G43-51. [PMID: 26492921 DOI: 10.1152/ajpgi.00222.2015] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/17/2015] [Indexed: 01/31/2023]
Abstract
Enteropancreatic hormone secretion is thought to include a cephalic phase, but the evidence in humans is ambiguous. We studied vagally induced gut hormone responses with and without muscarinic blockade in 10 glucose-clamped healthy men (age: 24.5 ± 0.6 yr, means ± SE; body mass index: 24.0 ± 0.5 kg/m(2); HbA1c: 5.1 ± 0.1%/31.4 ± 0.5 mmol/mol). Cephalic activation was elicited by modified sham feeding (MSF, aka "chew and spit") with or without atropine (1 mg bolus 45 min before MSF + 80 ng·kg(-1)·min(-1) for 2 h). To mimic incipient prandial glucose excursions, glucose levels were clamped at 6 mmol/l on all days. The meal stimulus for the MSF consisted of an appetizing breakfast. Participants (9/10) also had a 6 mmol/l glucose clamp without MSF. Pancreatic polypeptide (PP) levels rose from 6.3 ± 1.1 to 19.9 ± 6.8 pmol/l (means ± SE) in response to MSF and atropine lowered basal PP levels and abolished the MSF response. Neither insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP), nor glucagon-like peptide-1 (GLP-1) levels changed in response to MSF or atropine. Glucagon and ghrelin levels were markedly attenuated by atropine prior to and during the clamp: at t = 105 min on the atropine (ATR) + clamp (CLA) + MSF compared with the saline (SAL) + CLA and SAL + CLA + MSF days; baseline-subtracted glucagon levels were -10.7 ± 1.1 vs. -4.0 ± 1.1 and -4.7 ± 1.9 pmol/l (means ± SE), P < 0.0001, respectively; corresponding baseline-subtracted ghrelin levels were 303 ± 36 vs. 39 ± 38 and 3.7 ± 21 pg/ml (means ± SE), P < 0.0001. Glucagon and ghrelin levels were unaffected by MSF. Despite adequate PP responses, a cephalic phase response was absent for insulin, glucagon, GLP-1, GIP, and ghrelin.
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Affiliation(s)
- Simon Veedfald
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; and Department of Surgical Gastroenterology, Rigshospitalet, University of Copenhagen, Denmark
| | - Astrid Plamboeck
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; and
| | - Carolyn F Deacon
- Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; and
| | - Bolette Hartmann
- Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; and
| | - Filip K Knop
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; and
| | - Tina Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; and
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Plamboeck A, Veedfald S, Deacon CF, Hartmann B, Vilsbøll T, Knop FK, Holst JJ. The role of efferent cholinergic transmission for the insulinotropic and glucagonostatic effects of GLP-1. Am J Physiol Regul Integr Comp Physiol 2015; 309:R544-51. [DOI: 10.1152/ajpregu.00123.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/29/2015] [Indexed: 01/26/2023]
Abstract
The importance of vagal efferent signaling for the insulinotropic and glucagonostatic effects of glucagon-like peptide-1 (GLP-1) was investigated in a randomized single-blinded study. Healthy male participants ( n = 10) received atropine to block vagal cholinergic transmission or saline infusions on separate occasions. At t = 15 min, plasma glucose was clamped at 6 mmol/l. GLP-1 was infused at a low dose (0.3 pmol·kg−1·min−1) from t = 45–95 min and at a higher dose (1 pmol·kg−1·min−1) from t = 95–145 min. Atropine blocked muscarinic, cholinergic transmission, as evidenced by an increase in heart rate [peak: 70 ± 2 (saline) vs. 90 ± 2 (atropine) beats/min, P < 0.002] and suppression of pancreatic polypeptide levels [area under the curve during the GLP-1 infusions (AUC45–145): 492 ± 85 (saline) vs. 247 ± 59 (atropine) pmol/l × min, P < 0.0001]. More glucose was needed to maintain the clamp during the high-dose GLP-1 infusion steady-state period on the atropine day [6.4 ± 0.9 (saline) vs. 8.7 ± 0.8 (atropine) mg·kg−1·min−1, P < 0.0023]. GLP-1 dose-dependently increased insulin secretion on both days. The insulinotropic effect of GLP-1 was not impaired by atropine [C-peptide AUCs45–145: 99 ± 8 (saline) vs. 113 ± 13 (atropine) nmol/l × min, P = 0.19]. Atropine suppressed glucagon levels additively with GLP-1 [AUC45–145: 469 ± 70 (saline) vs. 265 ± 50 (atropine) pmol/l × min, P = 0.018], resulting in hypoglycemia when infusions were suspended [3.6 ± 0.2 (saline) vs. 2.7 ± 0.2 (atropine) mmol/l, P < 0.0001]. To ascertain whether atropine could independently suppress glucagon levels, control experiments ( n = 5) were carried out without GLP-1 infusions [AUC45–145: 558 ± 103 (saline) vs. 382 ± 76 (atropine) pmol/l × min, P = 0.06]. Our results suggest that efferent muscarinic activity is not required for the insulinotropic effect of exogenous GLP-1 but that blocking efferent muscarinic activity independently suppresses glucagon secretion. In combination, GLP-1 and muscarinic blockade strongly affect glucose turnover.
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Affiliation(s)
- Astrid Plamboeck
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- The Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Simon Veedfald
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- The Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
- Department of Surgical Gastroenterology and Liver Transplantation, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Carolyn F. Deacon
- The Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Bolette Hartmann
- The Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Tina Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Filip K. Knop
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- The Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Jens J. Holst
- The Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
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Rodriguez-Diaz R, Caicedo A. Novel approaches to studying the role of innervation in the biology of pancreatic islets. Endocrinol Metab Clin North Am 2013; 42:39-56. [PMID: 23391238 PMCID: PMC3576136 DOI: 10.1016/j.ecl.2012.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The autonomic nervous system helps regulate glucose homeostasis by acting on pancreatic islets of Langerhans. Despite decades of research on the innervation of the pancreatic islet, the mechanisms used by the autonomic nervous input to influence islet cell biology have not been elucidated. This article discusses how these barriers can be overcome to study the role of the autonomic innervation of the pancreatic islet in glucose metabolism. It describes recent advances in microscopy and novel approaches to studying the effects of nervous input that may help clarify how autonomic axons regulate islet biology.
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Affiliation(s)
- Rayner Rodriguez-Diaz
- Diabetes Research Institute, Miller School of Medicine, University of Miami, FL 33136
| | - Alejandro Caicedo
- Diabetes Research Institute, Miller School of Medicine, University of Miami, FL 33136
- Department of Medicine, Miller School of Medicine, University of Miami, FL 33136
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, FL 33136
- Program in Neuroscience, Miller School of Medicine, University of Miami, FL 33136
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Tornehave D, Kristensen P, Rømer J, Knudsen LB, Heller RS. Expression of the GLP-1 receptor in mouse, rat, and human pancreas. J Histochem Cytochem 2008; 56:841-51. [PMID: 18541709 DOI: 10.1369/jhc.2008.951319] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We studied the intra-islet localization of the glucagon-like peptide 1 receptor (GLP-1R) by colocalization studies of the GLP-1R mRNA and protein with islet cell hormones in mice, rats, and humans. In contrast to previous reports, we show that the GLP-1R is selectively located on the beta cells. The localization of GLP-1R in islets and ducts was studied using ISH and double and triple fluorescence microscopy. In normal pancreatic tissue from mice and rats, GLP-1R mRNA was only detectable in the beta cells. Double and triple immunofluorescence using two different GLP-1R antisera and combinations of insulin, glucagon, pancreatic polypeptide, and somatostatin showed that GLP-1R protein is almost exclusively colocalized with insulin. The same pattern was observed in human pancreas, but the GLP-1R expression was more heterogeneous, with populations of insulin immunoreactive cells with high and low expression. This is the first time that the GLP-1R has been localized in human islets. Furthermore, GLP-1R immunoreactivity was found in the pancreatic ducts in mouse, rat, and human pancreas. As an important confirmation of the specificity of our methods, we found no signals for GLP-1R mRNA or protein in pancreatic tissue from gene-targeted GLP-1R-deficient mice. In conclusion, our data suggest that the GLP-1 receptor is restricted to the pancreatic beta cells and the lack of receptor immunoreactivity on delta cells cannot be explained suitably to correspond with published in vivo and in vitro data. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
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Affiliation(s)
- Ditte Tornehave
- Department of Developmental Biology, Hagedorn Research Institute, Niels Steensensvej 6, DK2820 Gentofte, Denmark
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Brunicardi FC, Shavelle DM, Andersen DK. Neural regulation of the endocrine pancreas. INTERNATIONAL JOURNAL OF PANCREATOLOGY : OFFICIAL JOURNAL OF THE INTERNATIONAL ASSOCIATION OF PANCREATOLOGY 1995; 18:177-95. [PMID: 8708389 DOI: 10.1007/bf02784941] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- F C Brunicardi
- Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA
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Brunicardi FC, Elahi D, Andersen DK. Splanchnic neural regulation of somatostatin secretion in the isolated perfused human pancreas. Ann Surg 1994; 219:258-66. [PMID: 7908511 PMCID: PMC1243133 DOI: 10.1097/00000658-199403000-00005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE The somatostatin-secreting delta cells in the islets of Langerhans appear to be regulated by neural mechanisms that have not been defined clearly. In this study, the celiac neural bundle of the human pancreas was electrically stimulated in the presence and absence of selective neural antagonists. SUMMARY BACKGROUND DATA The authors previously reported on studies of the splanchnic neural regulation of insulin, glucagon, and pancreatic polypeptide secretion. In these studies, alpha-adrenergic fibers appeared to have a predominant effect, strongly inhibiting the secretion of insulin, glucagon, and pancreatic polypeptide secretion. Cholinergic fibers appeared to stimulate strongly, although beta-adrenergic fibers weakly stimulated, the secretion of these hormones. Investigations of neural regulatory mechanisms governing human somatostatin release in vitro have not been previously reported. METHODS Pancreata were obtained from eight cadaveric organ donors. The isolated perfused human pancreas technique was used to assess the regulation of somatostatin secretion by the various neural fibers contained within the celiac plexus. The secretory response of somatostatin was examined in the presence of 16.7 mmol/L glucose, with and without neural stimulation, and specific neural antagonists. RESULTS The basal somatostatin secretion was 88 +/- 26 fmol/g/min and increased 131 +/- 23% (n = 8, p < 0.01) in response to 16.7 mmol/L glucose. The augmentation seen with glucose was inhibited 66 +/- 22% (n = 8, p < 0.05) during celiac neural bundle stimulation. Alpha-adrenergic blockade resulted in a 90 +/- 30% (n = 6, p < 0.01) augmentation of somatostatin release. Beta-adrenergic blockade caused a 13 +/- 2% (n = 6, p < 0.05) suppression of somatostatin release. Complete adrenergic blockade resulted in a 25 +/- 23% (n = 5, p = not significant) inhibition of somatostatin release. Cholinergic blockade resulted in a 40 +/- 10% (n = 6, p < 0.02) suppression of somatostatin release. CONCLUSIONS The predominant effect of celiac neural bundle stimulation was inhibition of somatostatin secretion through an alpha-adrenergic effect. Beta-adrenergic fibers stimulate somatostatin secretion; cholinergic fibers have a negligible effect on somatostatin secretion. These data suggest that the splanchnic innervation of the pancreas has a potent regulatory role in somatostatin release in this in vitro human model.
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Affiliation(s)
- F C Brunicardi
- Department of Surgery and Medicine, State University of New York, Health Science Center at Brooklyn
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Weigert N, Dollinger M, Schmid R, Schusdziarra V. Contribution of neural intrapancreatic non-cholinergic non-adrenergic mechanisms to glucose-induced insulin release in the isolated rat pancreas. Diabetologia 1992; 35:1133-9. [PMID: 1478364 DOI: 10.1007/bf00401366] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In the isolated rat pancreas the effect of intrapancreatic non-adrenergic non-cholinergic nerves was examined upon insulin, glucagon and somatostatin release during perturbations of perfusate glucose. Elevation of glucose from 1.6 to 8.3 mmol/l increased insulin and somatostatin secretion and inhibited glucagon release. The first phase of insulin secretion was significantly reduced by the neurotoxin tetrodotoxin to 55% of the controls (p < 0.05). The somatostatin response was attenuated by tetrodotoxin while the change of glucagon remained unaffected. In contrast the combined adrenergic and cholinergic blockade with atropine, phentolamine and propranolol (10(-5) mol/l) did not modify the insulin, glucagon and somatostatin response. When glucose was changed from 8.3 to 1.6 mmol/l, the reduction of insulin and somatostatin release was not modified by tetrodotoxin, but stimulation of glucagon was significantly attenuated by 60-70% (p < 0.03), which was similar to the effect of combined adrenergic and cholinergic blockade. Subsequently, the effect of neural blockade was examined during more physiological perturbations of perfusate glucose levels. When glucose was changed from 3.9 to 7.2 mmol/l, tetrodotoxin also attenuated first phase insulin response by 40% while cholinergic and adrenergic blockade had no effect. The nitric oxide synthase inhibitor NG-Nitro-L-arginine-methyl-ester (L-NAME) did not alter the glucose-induced insulin response indicating that nitric oxide is not involved in this mechanism. It is concluded that neural non-adrenergic non-cholinergic mechanisms contribute to the first, but not second phase of glucose-induced insulin release. Non-adrenergic non-cholinergic effects do not participate in regulation of glucagon and somatostatin secretion under the conditions employed.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- N Weigert
- Department of Internal Medicine II, Technical University of Munich, FRG
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Järhult J, Farnebo LO, Graffner H, Holst J. Effects of physiological increases in plasma noradrenaline on the human endocrine pancreas. J Endocrinol Invest 1989; 12:401-4. [PMID: 2570094 DOI: 10.1007/bf03350710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of plasma noradrenaline concentrations within the physiological range (less than 5-6 nM) on the endocrine pancreas was investigated in 9 nondiabetic volunteers. Noradrenaline significantly inhibited plasma insulin levels but did not change plasma glucagon and somatostatin concentrations.
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Affiliation(s)
- J Järhult
- Department of Surgery, Eksjö Hospital, Sweden
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Nishi S, Seino Y, Ishida H, Seno M, Taminato T, Sakurai H, Imura H. Vagal regulation of insulin, glucagon, and somatostatin secretion in vitro in the rat. J Clin Invest 1987; 79:1191-6. [PMID: 2881948 PMCID: PMC424307 DOI: 10.1172/jci112936] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Using a new in vitro procedure of the isolated perfused rat pancreas with vagal innervation, electrical vagal stimulation produced an increase in both insulin and glucagon secretion in proportion to the pulse frequency, but an inhibition in somatostatin release. When atropine was infused, both insulin and glucagon responses to vagal stimulation were partially suppressed, whereas somatostatin release was enhanced. In the presence of hexamethonium, vagal stimulation failed to affect insulin, glucagon, or somatostatin secretion. Propranolol partially blocked both insulin and glucagon responses but did not influence somatostatin response. Phentolamine had no significant effect on release of hormones. Simultaneous administration of propranolol and phentolamine tended to inhibit both insulin and glucagon responses to vagal stimulation. These findings suggest that not only a cholinergic but also a noncholinergic neuron may be involved in vagal regulation of pancreatic hormone secretion and that these neurons may be under the control of preganglionic vagal fibers via nicotinic receptors.
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Seino Y, Nishi S, Imura H. Vagal modulation of arginine- and glucagon-induced pancreatic somatostatin secretion. Life Sci 1985; 37:651-6. [PMID: 2862561 DOI: 10.1016/0024-3205(85)90432-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In order to elucidate the role of the vagus nerve in the regulation of pancreatic somatostatin secretion, the effect of electrical stimulation of the vagus on the isolated perfused rat pancreas was studied. Somatostatin release induced by 19 mM arginine in the presence of 11 mM glucose or 10(-6)M glucagon in the presence of 5.5 mM glucose was suppressed by vagal stimulation. This suppressive effect on somatostatin was eliminated in the presence of 10(-5)M atropine plus glucagon, while somatostatin release was significantly enhanced in the presence of atropine plus arginine. We conclude that pancreatic somatostatin secretion may be regulated not only by a cholinergic inhibitory neuron but also by a stimulatory non-cholinergic neuron.
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Affiliation(s)
- J.J. Holst
- Institute of Medical Physiology Cthe Panum InstituteUniversity of CopenhagenDenmark
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