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Najenson AC, Bianchi M, Courreges AP, Rodriguez MR, Casco VH, Vatta MS, Bianciotti LG. The exocrine pancreas is an extracardiac source of atrial natriuretic peptide. Pflugers Arch 2019; 471:915-924. [PMID: 30623208 DOI: 10.1007/s00424-018-02247-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 10/27/2022]
Abstract
Previous studies have shown that atrial natriuretic peptide (ANP) regulates exocrine pancreatic function in health and disease. As extracardiac sources of ANP have been identified and ANP-like immunoreactivity has been reported in the exocrine pancreas, in the present work we sought to establish whether ANP was produced in the rat exocrine pancreas and if conditions like fasting/feeding or acute pancreatitis were reflected on ANP expression. By using RT-PCR, immunoblotting, and immunofluorescence microscopy assays, it was found that both mRNA and protein ANP were present in the acinar cells of the exocrine pancreas. The amount of ANP in the pancreas was lower in than the atrium but similar to other tissues like the kidney and liver. Immunogold labeling electron microscopy studies revealed that ANP was localized in zymogen granules and the endoplasmic reticulum suggesting local synthesis and package into granules. ANP protein expression was significantly increased not only in fasting but also in acute pancreatitis, the latter probably related to impaired secretion. Natriuretic peptide receptor type C which mediates ANP biological effects in the exocrine pancreas was also present in acinar cells and its expression did not change with either fasting or acute pancreatitis. Present findings show that the exocrine pancreas is a relatively important extracardiac source of ANP and further support previous studies strongly suggesting the active role of the peptide in pancreatic physiology and pathophysiology.
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Affiliation(s)
- Ana C Najenson
- Facultad de Farmacia y Bioquímica, Cátedra de Genética, Universidad de Buenos Aires, Buenos Aires, Argentina.,CONICET-Instituto de Inmunología, Genética y Metabolismo (INIGEM), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mariana Bianchi
- Facultad de Ingeniería-Bioingeniería, Laboratorio de Microscopía Aplicada a Estudios Moleculares y Celulares, Universidad Nacional de Entre Ríos, Paraná, Entre Ríos, Argentina
| | - Ana P Courreges
- Facultad de Farmacia y Bioquímica, Cátedra de Genética, Universidad de Buenos Aires, Buenos Aires, Argentina.,CONICET-Instituto de Inmunología, Genética y Metabolismo (INIGEM), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Myrian R Rodriguez
- CONICET-Instituto de Inmunología, Genética y Metabolismo (INIGEM), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Víctor H Casco
- Facultad de Ingeniería-Bioingeniería, Laboratorio de Microscopía Aplicada a Estudios Moleculares y Celulares, Universidad Nacional de Entre Ríos, Paraná, Entre Ríos, Argentina
| | - Marcelo S Vatta
- Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Universidad de Buenos Aires, Buenos Aires, Argentina.,CONICET-Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Liliana G Bianciotti
- CONICET-Instituto de Inmunología, Genética y Metabolismo (INIGEM), Universidad de Buenos Aires, Buenos Aires, Argentina. .,Facultad de Farmacia y Bioquímica, Cátedra de Fisiopatología, Universidad de Buenos Aires, Junín 956 (11 13), Buenos Aires, Argentina.
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Najenson AC, Courreges AP, Perazzo JC, Rubio MF, Vatta MS, Bianciotti LG. Atrial natriuretic peptide reduces inflammation and enhances apoptosis in rat acute pancreatitis. Acta Physiol (Oxf) 2018; 222. [PMID: 29117461 DOI: 10.1111/apha.12992] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 10/20/2017] [Accepted: 10/30/2017] [Indexed: 12/18/2022]
Abstract
AIM We previously reported that atrial natriuretic peptide (ANP) reduces serum amylase and intrapancreatic trypsinogen activation in the onset of acute pancreatitis whereas secretin increases them. In the present work, we sought to establish the effect of ANP and secretin on the inflammatory response and cell death in experimental acute pancreatitis. METHODS The expression and activity of key inflammatory mediators and apoptosis were evaluated in the presence or absence of the atrial peptide, secretin or both in cerulein-induced acute pancreatitis in rats. Also, ultrastructural changes in pancreatic acinar cells were assessed by transmission electron microscopy. RESULTS ANP significantly reduced NF-κB activation and TNF-α intrapancreatic levels. Furthermore, it decreased inducible nitric oxide synthase and cyclooxygenase 2 expression and activity while it diminished myeloperoxidase activity. ANP also stimulated apoptosis as shown by caspase-3 expression and activation as well as TUNEL assay. These findings correlated well with the ultrastructural changes observed in the exocrine pancreas. Although secretin reduced various inflammatory markers, it also diminished caspase-3 activation and the overall response was the aggravation of the disease as reflected by the ultrastructural alterations of pancreatic acinar cells. In the presence of ANP, various effects evoked by secretin were antagonized. CONCLUSION Present findings show that ANP significantly attenuated the severity of acute pancreatitis in the rat by inducing apoptosis and reducing the inflammatory response and further suggest that ANP may have eventual therapeutic implications in the disease and/or in medical interventions at risk of its developing like endoscopic retrograde cholangiopancreatography.
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Affiliation(s)
- A. C. Najenson
- Instituto de Inmunología; Genética y Metabolismo (INIGEM-CONICET-UBA); Facultad de Farmacia y Bioquímica; Universidad de Buenos Aires; Buenos Aires Argentina
| | - A. P. Courreges
- Instituto de Inmunología; Genética y Metabolismo (INIGEM-CONICET-UBA); Facultad de Farmacia y Bioquímica; Universidad de Buenos Aires; Buenos Aires Argentina
| | - J. C. Perazzo
- Instituto de Patología; Facultad de Medicina; Universidad de Buenos Aires; Buenos Aires Argentina
| | - M. F. Rubio
- Instituto de Investigaciones Médicas (IDIM-CONICET-UBA); Facultad de Medicina; Universidad de Buenos Aires; Buenos Aires Argentina
| | - M. S. Vatta
- Cátedra de Fisiología-Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET-UBA); Facultad de Farmacia y Bioquímica; Universidad de Buenos Aires; Buenos Aires Argentina
| | - L. G. Bianciotti
- Instituto de Inmunología; Genética y Metabolismo (INIGEM-CONICET-UBA); Facultad de Farmacia y Bioquímica; Universidad de Buenos Aires; Buenos Aires Argentina
- Departamento de Ciencias Biológicas; Cátedra de Fisiopatología; Facultad de Farmacia y Bioquímica; Universidad de Buenos Aires; Buenos Aires Argentina
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The C-type natriuretic peptide induces thermal hyperalgesia through a noncanonical Gβγ-dependent modulation of TRPV1 channel. J Neurosci 2012; 32:11942-55. [PMID: 22933780 DOI: 10.1523/jneurosci.1330-12.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Natriuretic peptides (NPs) control natriuresis and normalize changes in blood pressure. Recent studies suggest that NPs are also involved in the regulation of pain sensitivity, although the underlying mechanisms remain essentially unknown. Many biological effects of NPs are mediated by guanylate cyclase (GC)-coupled NP receptors, NPR-A and NPR-B, whereas the third NP receptor, NPR-C, lacks the GC kinase domain and acts as the NP clearance receptor. In addition, NPR-C can couple to specific Gα(i)-Gβγ-mediated intracellular signaling cascades in numerous cell types. We found that NPR-C is coexpressed in transient receptor potential vanilloid-1 (TRPV1)-expressing mouse dorsal root ganglia (DRG) neurons. NPR-C can be coimmunoprecipitated with Gα(i), and C-type natriuretic peptide (CNP) treatment induced translocation of protein kinase Cε (PKCε) to the plasma membrane of these neurons, which was inhibited by pertussis toxin pretreatment. Application of CNP potentiated capsaicin- and proton-activated TRPV1 currents in cultured mouse DRG neurons and increased their firing frequency, an effect that was absent in DRG neurons from TRPV1(-/-) mice. CNP-induced sensitization of TRPV1 activity was attenuated by pretreatment of DRG neurons with the specific inhibitors of Gβγ, phospholipase C-β (PLCβ), or PKC, but not of protein kinase A, and was abolished by mutations at two PKC phosphorylation sites in TRPV1. Furthermore, CNP injection into mouse hindpaw led to the development of thermal hyperalgesia that was attenuated by administration of specific inhibitors of Gβγ or TRPV1 and was also absent in TRPV1(-/-) mice. Thus, our work identifies the Gβγ-PLCβ-PKC-dependent potentiation of TRPV1 as a novel signaling cascade recruited by CNP in mouse DRG neurons that can lead to enhanced nociceptor excitability and thermal hypersensitivity.
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Rodríguez MR, Diez F, Ventimiglia MS, Morales V, Copsel S, Vatta MS, Davio CA, Bianciotti LG. Atrial natriuretic factor stimulates efflux of cAMP in rat exocrine pancreas via multidrug resistance-associated proteins. Gastroenterology 2011; 140:1292-302. [PMID: 21237168 DOI: 10.1053/j.gastro.2010.12.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 12/02/2010] [Accepted: 12/27/2010] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Atrial natriuretic factor (ANF) prevents increases in intracellular levels of cAMP that are induced by secretin in the exocrine pancreas. We investigated the contribution of cyclic adenosine monophosphate (cAMP) efflux to ANF inhibition of secretin signaling. METHODS Intracellular and extracellular cAMP were measured by radio-binding assays in isolated pancreatic acini exposed to secretin and other secretagogues, alone or with ANF. Levels of messenger RNA for multidrug resistance-associated protein (MRP)4, MRP5, and MRP8 were measured by real-time polymerase chain reaction. MRP4 was knocked down in AR42J cells by small interfering RNA. In vivo studies were performed in rats. RESULTS Pancreatic secretagogues increased levels of intracellular cAMP, but only secretin and vasoactive intestinal peptide promoted cAMP efflux; efflux was increased by ANF, through signaling via natriuretic peptide receptor-C and phospholipase C-protein kinase C. In time-course studies with active phosphodiesterases, levels of intracellular and extracellular cAMP increased earlier after the addition of secretin and ANF (1 min) than after the addition of secretin alone (3 min). Similar kinetic patterns occurred with a phosphodiesterase inhibitor. A probenecid-sensitive transporter mediated cAMP egression. The main cAMP transporter, MRP4, was expressed in AR42J cells and pancreas. cAMP egression occurred in AR42J cells exposed to secretin, but this response was reduced in cells that expressed MRP4 small interfering RNA. In rats, levels of cAMP in plasma and pancreatic juice increased after infusion with secretin alone or secretin plus ANF. CONCLUSIONS ANF signals via natriuretic peptide receptor-C coupled to the phospholipase C-protein kinase C pathway to increase secretin-induced efflux of cAMP, probably through MPR-4. Cyclic AMP extrusion might be a mechanism, in addition to phosphodiesterase action, to regulate intracellular cAMP levels in pancreatic acinar cells.
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Affiliation(s)
- Myrian R Rodríguez
- Cátedras de Fisiopatología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
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Gu XY, Cai ZX, Yuan H, Wu TH, Li J, Guo HS. Effects of Dendroaspis natriuretic peptide on delayed rectifier potassium currents and its mechanism. ACTA ACUST UNITED AC 2009; 155:115-20. [PMID: 19245821 DOI: 10.1016/j.regpep.2009.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2008] [Revised: 12/10/2008] [Accepted: 02/03/2009] [Indexed: 11/25/2022]
Abstract
Dendroaspis natriuretic peptide (DNP), a newly-described natriuretic peptide, plays an inhibitory role in smooth muscle motility of the gastrointestinal tract. However, the effect of DNP on delayed rectifier potassium currents I(K(V)) is still unclear. In this study, we sought to investigate the effect of DNP on I(K(V)) and its mechanism in gastric antral circular smooth muscle cells using the whole-cell patch-clamp technique. DNP significantly inhibited I(K(V)) in a concentration-dependent manner. LY83583 (1 micromol/l), a guanylate cyclase inhibitor, significantly impaired DNP-induced inhibition of I(K(V)). Moreover, DNP-induced inhibition in I(K(V)) was potentiated by the cyclic guanosine monophosphate (cGMP) sensitive phosphoesterase inhibitor zaparinast (0.1 micromol/l). DNP-induced inhibition of I(K(V)) was completely blocked by KT5823, an inhibitor of cGMP-dependent protein kinase G(PKG), but not affected by KT-5720, a PKA-specific inhibitor. Taken together, our results suggest that DNP inhibits I(K(V)) via the cGMP/PKG-dependent signaling axis instead of the cAMP/PKA pathway.
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Affiliation(s)
- Xin-Yi Gu
- Department of internal medicine, Affiliated Zhongshan Hospital of Dalian University, Dalian 116001, China
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Natriuretic peptides as regulatory mediators of secretory activity in the digestive system. ACTA ACUST UNITED AC 2009; 154:5-15. [PMID: 19233231 DOI: 10.1016/j.regpep.2009.02.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/28/2009] [Accepted: 02/03/2009] [Indexed: 11/22/2022]
Abstract
Atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) are members of the natriuretic peptide family best known for their role in blood pressure regulation. However, in recent years all the natriuretic peptides and their receptors have been described in the gastrointestinal tract, digestive glands and central nervous system, as well as implicated in the regulation of digestive gland functions. The current review highlights the regulatory role of ANP and CNP in pancreatic and other digestive secretions. ANP and CNP stimulate basal as well as induced pancreatic secretion and modify bicarbonate and chloride secretions. Whereas ANP and CNP exert effects directly on pancreatic cells, CNP also acts through a vago-vagal reflex. At high doses both peptides attenuate pancreatic secretion induced by high doses of secretin through the PLC/PKC pathway. With regards to other digestive secretions, ANP and CNP decrease bile secretion in the rat. ANP does not induce salivation by itself but enhances stimulated salivary secretion and modifies salivary composition in rat parotid as well as submandibular glands. In rat pancreatic, hepatic, parotid and submandibular tissues, the NPR-C receptor mediates mostly peripheral responses whereas NPR-A and NPR-B receptors, which are coupled to guanylate cyclase, likely mediate the central response. In addition, ANP modulates gastric acid secretion via a vagal-dependent mechanism. In the intestine, ANP and CNP decrease water and sodium chloride absorption through an increase in cGMP levels. Overall, these findings indicate that ANP and CNP are members of the large group of regulatory peptides affecting digestive secretions.
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Chen LA, Li J, Silva SR, Jackson LN, Zhou Y, Watanabe H, Ives KL, Hellmich MR, Evers BM. PKD3 is the predominant protein kinase D isoform in mouse exocrine pancreas and promotes hormone-induced amylase secretion. J Biol Chem 2009; 284:2459-71. [PMID: 19028687 PMCID: PMC2629096 DOI: 10.1074/jbc.m801697200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 10/14/2008] [Indexed: 11/06/2022] Open
Abstract
The protein kinase D (PKD) family of serine/threonine kinases, which can be activated by gastrointestinal hormones, consists of three distinct isoforms that modulate a variety of cellular processes including intracellular protein transport as well as constitutive and regulated secretion. Although isoform-specific functions have been identified in a variety of cell lines, the expression and function of PKD isoforms in normal, differentiated secretory tissues is unknown. Here, we demonstrate that PKD isoforms are differentially expressed in the exocrine and endocrine cells of the pancreas. Specifically, PKD3 is the predominant isoform expressed in exocrine cells of the mouse and human pancreas, whereas PKD1 and PKD2 are more abundantly expressed in the pancreatic islets. Within isolated mouse pancreatic acinar cells, PKD3 undergoes rapid membrane translocation, trans-activating phosphorylation, and kinase activation after gastrointestinal hormone or cholinergic stimulation. PKD phosphorylation in pancreatic acinar cells occurs viaaCa2+-independent, diacylglycerol- and protein kinase C-dependent mechanism. PKD phosphorylation can also be induced by physiologic concentrations of secretagogues and by in vivo stimulation of the pancreas. Furthermore, activation of PKD3 potentiates MEK/ERK/RSK (RSK, ribosomal S6 kinase) signaling and significantly enhances cholecystokinin-mediated pancreatic amylase secretion. These findings reveal a novel distinction between the exocrine and endocrine cells of the pancreas and further identify PKD3 as a signaling molecule that promotes hormone-stimulated amylase secretion.
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Affiliation(s)
- L Andy Chen
- Department of Surgery and Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas 77555-0536, USA
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Cai CY, Cai ZX, Gu XY, Shan LJ, Wang YX, Yin XZ, Qi QH, Guo HS. Dendroaspis natriuretic peptide relaxes gastric antral circular smooth muscle of guinea-pig through the cGMP/cGMP-dependent protein kinase pathway. World J Gastroenterol 2008; 14:5461-6. [PMID: 18803360 PMCID: PMC2744167 DOI: 10.3748/wjg.14.5461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To systematically investigate if cGMP/cGMP-dependent protein kinase G (PKG) signaling pathway may participate in dendroaspis natriuretic peptide (DNP)-induced relaxation of gastric circular smooth muscle.
METHODS: The content of cGMP in guinea pig gastric antral smooth muscle tissue and perfusion solution were measured using radioimmunoassay; spontaneous contraction of gastric antral circular muscles recorded using a 4-channel physiograph; and Ca2+-activated K+ currents (IK(Ca)) and spontaneous transient outward currents (STOCs) in isolated gastric antral myocytes were recorded using the whole-cell patch clamp technique.
RESULTS: DNP markedly enhanced cGMP levels in gastric antral smooth muscle tissue and in the perfusion medium. DNP induced relaxation in gastric antral circular smooth muscle, which was inhibited by KT5823, a cGMP-dependent PKG inhibitor. DNP increased IK(Ca). This effect was almost completely blocked by KT5823, and partially blocked by LY83583, an inhibitor of guanylate cyclase to change the production of cGMP. DNP also increased STOCs. The effect of DNP on STOCs was abolished in the presence of KT5823, but not affected by KT-5720, a PKA-specific inhibitor.
CONCLUSION: DNP activates IK(Ca) and relaxes guinea-pig gastric antral circular smooth muscle via the cGMP/PKG-dependent singling axis instead of cAMP/PKA pathway.
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Receptor-mediated signal transduction pathways and the regulation of pancreatic acinar cell function. Curr Opin Gastroenterol 2008; 24:573-9. [PMID: 19122497 DOI: 10.1097/mog.0b013e32830b110c] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Recent studies on pancreatic acinar cell function have led to a more detailed understanding of the signal transduction mechanisms regulating digestive enzyme synthesis and secretion as well as pancreatic growth. This review identifies and puts into context these recent studies, which further understanding in these areas. RECENT FINDINGS Receptors present on acinar cells, particularly those for cholecystokinin and secretin, have been better characterized as to the molecular nature of the ligand-receptor interaction. Other reports have described the receptors for natriuretic peptides and fibroblast growth factor on acini. Intracellular Ca(2+) signaling remains at the center of stimulus secretion coupling and its regulation by inositol 1,4,5-trisphosphate, nicotinic acid adenine dinucleotide phosphate and cyclic ADP-ribose has been further defined. Work downstream of intracellular mediators has focused on molecular mechanisms of exocytosis particularly involving small G proteins, soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and cytoskeletal proteins. Considerable progress has been made defining the complex in acinar cells and its regulation. In addition to secretion, recent studies have further defined the regulation of pancreatic growth both in adaptive regulation to diet and hormones, particularly cholecystokinin, and in the regeneration that occurs after pancreatitis or partial pancreatectomy. This regulation involves calcineurin-nuclear factor of activated T cells, mammalian target of rapamycin, mitogen-activated protein kinase, Notch signaling pathways as well as various tyrosine kinases. SUMMARY Understanding the mechanisms that regulate pancreatic acinar cell function is contributing to our knowledge of normal pancreatic function and alterations in diseases such as pancreatitis and pancreatic cancer.
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Atrial natriuretic factor intracellular signaling in the rat submandibular gland. ACTA ACUST UNITED AC 2008; 150:43-9. [PMID: 18455250 DOI: 10.1016/j.regpep.2008.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 01/16/2008] [Accepted: 03/14/2008] [Indexed: 11/23/2022]
Abstract
We previously reported that intravenously administered atrial natriuretic factor (ANF) induced no salivation but enhanced agonist-evoked secretion in submandibular glands. The gene expression of ANF and natriuretic peptide receptors (NPR) was later reported in the glands. In the present study we sought to establish the intracellular signalling mechanisms underlying ANF modulation of salivary secretion. Fasted rats were prepared with submandibular duct and femoral cannulation. Dose-response curves to methacholine (MC) and norepinephrine (NE) were performed in the presence of cANP (4-23 amide) (selective NPR-C agonist) and ANF. Local injection of the agonist or ANF-induced no salivation, but enhanced MC and NE-evoked secretion. ANF and cANP (4-23 amide) enhanced phosphoinositide turnover being the effect abolished by U73122 (PLC inhibitor). Further ANF and cANP (4-23 amide) decreased basal cAMP content but failed to affect isoproterenol or forskolin-evoked cAMP. ANF response was inhibited by pertussis toxin and mimicked by cANP (4-23 amide) strongly supporting NPR-C activation. ANF-induced cAMP reduction was abolished by PLC and PKC inhibitors. The content of cGMP was dose dependently stimulated by ANF but not modified by cANP (4-23 amide). These findings support that ANF through NPR-C receptors coupled to PLC activation and adenylyl cyclase inhibition interacts with sialogogic agonists in the submandibular gland to potentiate salivation.
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Sabbatini ME, Rodríguez MR, Dabas P, Vatta MS, Bianciotti LG. C-type natriuretic peptide stimulates pancreatic exocrine secretion in the rat: role of vagal afferent and efferent pathways. Eur J Pharmacol 2007; 577:192-202. [PMID: 17900562 DOI: 10.1016/j.ejphar.2007.08.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Revised: 08/28/2007] [Accepted: 08/29/2007] [Indexed: 11/28/2022]
Abstract
We previously reported that C-type natriuretic peptide (CNP) increases amylase release in isolated pancreatic acini through natriuretic peptide receptor C activation and enhances pancreatic exocrine secretion via vagal pathways when applied to the brain. In the present study we sought to establish whether CNP was involved in the peripheral regulation of pancreatic secretion. Anesthetized rats were prepared with pancreatic duct cannulation, pyloric ligation and bile diversion into the duodenum. CNP dose-dependently enhanced pancreatic flow, chloride and protein excretion but did not modify bicarbonate output. A selective natriuretic peptide receptor C agonist enhanced pancreatic flow and mimicked CNP-evoked protein output but failed to modify chloride secretion. Truncal vagotomy, perivagal application of capsaicin and hexamethonium reduced CNP-evoked pancreatic flow and abolished chloride excretion but did not affect protein output. Furthermore, pre-treatment with atropine reduced both CNP-stimulated pancreatic flow and chloride excretion but failed to modify protein excretion. Partial muscarinic blockade of CNP-evoked chloride output suggested that mediators other than acetylcholine were involved. However, CNP response was unaltered by cholecystokinin and vasoactive intestinal peptide receptor blockade or by nitric oxide synthase inhibition. In conclusion, CNP-stimulated pancreatic flow through the activation of the natriuretic peptide receptor C and the vago-vagal reflex but it increased protein output only by natriuretic peptide receptor C activation and chloride excretion by vago-vagal reflexes. Present results suggest that CNP may play a role as a local regulator of the exocrine pancreas.
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Affiliation(s)
- María E Sabbatini
- Cátedra de Fisiopatología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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