451
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Ross GR, Yallampalli U, Yallampalli C. Cyclic AMP-independent CGRP8-37-sensitive receptors mediate adrenomedullin-induced decrease of CaCl2-contraction in pregnant rat mesenteric artery. J Vasc Res 2007; 45:33-44. [PMID: 17898545 DOI: 10.1159/000109075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 06/07/2007] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES We tested the hypothesis that adrenomedullin reduces calcium influx independent of potassium channels in depolarized endothelium-denuded mesenteric artery from pregnant rats. RESULTS Adrenomedullin reduced the CaCl(2)-induced contraction, while the receptor antagonist calcitonin gene-related peptide (CGRP)(8-37), but not adrenomedullin(22-52), reversed these effects. Adenylate cyclase inhibition by SQ22536 did not prevent adrenomedullin effects on CaCl(2)-induced contraction. Adrenomedullin did not inhibit depolarization-induced calcium entry to isolated vascular smooth muscle. Inhibition of myosin light-chain (MLC) phosphatase by calyculin A reversed the effects of adrenomedullin on contraction caused by submillimolar concentrations of CaCl(2), while adrenomedullin still inhibited contraction caused by higher concentrations of CaCl(2). However, the ratio of phosphorylated to total myosin phosphatase target 1, the regulatory subunit of MLC phosphatase, did not change with adrenomedullin, indicating a lack of MLC phosphatase activation. Interestingly, sodium fluoride, a nonspecific protein phosphatase inhibitor, completely blocked the effect of adrenomedullin on CaCl(2)-induced contraction. Adrenomedullin inhibited calcium mobilization from intracellular stores induced by thapsigargin. CONCLUSION Adrenomedullin inhibits CaCl(2)-induced contraction, without affecting calcium influx, through a CGRP(8-37)-sensitive receptor, but not using the cyclic adenosine monophosphate pathway, probably through activation of protein phosphatases. Inhibition of intracellular calcium release is an additional role played by adrenomedullin in calcium homeostasis in vascular smooth muscle.
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MESH Headings
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Adenylyl Cyclase Inhibitors
- Adenylyl Cyclases/metabolism
- Adrenomedullin/metabolism
- Adrenomedullin/pharmacology
- Animals
- Calcitonin Gene-Related Peptide/pharmacology
- Calcium Chloride/pharmacology
- Calcium Signaling/drug effects
- Calcium-Transporting ATPases/antagonists & inhibitors
- Calcium-Transporting ATPases/metabolism
- Cells, Cultured
- Cyclic AMP/metabolism
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Female
- Marine Toxins
- Membrane Potentials
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- Myosin-Light-Chain Phosphatase/antagonists & inhibitors
- Myosin-Light-Chain Phosphatase/metabolism
- Oxazoles/pharmacology
- Peptide Fragments/pharmacology
- Phosphorylation
- Potassium/metabolism
- Pregnancy
- Protein Phosphatase 1/metabolism
- Rats
- Receptors, Adrenomedullin
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, G-Protein-Coupled/metabolism
- Sodium Fluoride/pharmacology
- Thapsigargin/pharmacology
- Time Factors
- Vasoconstriction/drug effects
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- Gracious R Ross
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Tex., USA
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452
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Nicoletti P, Trevisani M, Manconi M, Gatti R, De Siena G, Zagli G, Benemei S, Capone JA, Geppetti P, Pini LA. Ethanol causes neurogenic vasodilation by TRPV1 activation and CGRP release in the trigeminovascular system of the guinea pig. Cephalalgia 2007; 28:9-17. [PMID: 17888011 DOI: 10.1111/j.1468-2982.2007.01448.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Ethanol stimulating transient receptor potential vanilloid 1 (TRPV1) on primary sensory neurons promotes neurogenic inflammation, including calcitonin gene-related peptide (CGRP)-mediated coronary dilation. Alcoholic beverages trigger migraine attacks and activation of trigeminal neurons plays a role in migraine. We have investigated in guinea pigs whether ethanol by TRPV1 stimulation causes neurogenic inflammation in the trigeminovascular system. Ethanol-evoked release of neuropeptides from slices of dura mater was abolished by Ca(2+) removal, capsaicin pretreatment and the TRPV1 antagonist, capsazepine. Intragastric ethanol increased plasma extravasation in dura mater, an effect abolished by capsazepine and the NK1 receptor antagonist, SR140333, and caused vasodilation around the middle meningeal artery, an effect abolished by capsazepine and the CGRP receptor antagonist, BIBN4096BS. Vasodilation of meningeal vessels by TRPV1 activation and CGRP release may be relevant to the mechanism by which alcohol ingestion triggers migraine attacks.
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Affiliation(s)
- P Nicoletti
- Clinical Pharmacology Unit, Department of Critical Care Medicine and Surgery, University of Florence, Florence, Italy
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453
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Li J, Kreicbergs A, Bergström J, Stark A, Ahmed M. Site-specific CGRP innervation coincides with bone formation during fracture healing and modeling: A study in rat angulated tibia. J Orthop Res 2007; 25:1204-12. [PMID: 17503519 DOI: 10.1002/jor.20406] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Sensory neuropeptide involved in local bone turnover is known, but poorly understood. In the present study, we analyze the occurrence of neuronal CGRP during healing and modeling of straight and angular tibial fractures in 74 rats. Bone healing and modeling was assessed by radiography and reinnervation by semi-quantitative immunohistochemistry method at fracture site between 1-12 weeks postfracture. The regenerating nerve fibers containing CGRP were observed in fracture callus as well as in close proximity to chondrocytes, with woven bone in both fractures already at week 1. Notably, it located predominantly on the concave side of angulated fracture in the manner of sprouting into bone from weeks 3 to 5 postfracture. In both fractures, fracture calluses peaked radiographically at week 3 postfracture. In angulated fracture, a reduction of 11% in callus thickness on convex side and an increase of 365% on concave side were noted from weeks 3 to 12. A 27-fold increase in total neuronal CGRP in straight fracture and 38-fold increases in angular fracture compared to intact bone was observed at week 3. In both types of fracture, neuronal CGRP was greater on the concave side than the convex; this difference was more pronounced in the angulated fracture. CGRP immunoreactivity clearly coincides with amount of new bone formation especially on the concave side of angulated fracture. The combined results suggest that fracture evokes an intense, localized in-growth of new nerve fibers containing CGRP, which may prove to be a prerequisite of fracture healing and modeling.
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Affiliation(s)
- Jian Li
- Section of Orthopaedics, Institution of Molecular Medicine and Surgery, Research Center M3:02, Karolinska University Hospital, SE 171 76, Stockholm, Sweden.
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454
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Zhong B, Wang DH. TRPV1 gene knockout impairs preconditioning protection against myocardial injury in isolated perfused hearts in mice. Am J Physiol Heart Circ Physiol 2007; 293:H1791-8. [PMID: 17586621 DOI: 10.1152/ajpheart.00169.2007] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the transient receptor potential vanilloid type 1 (TRPV1)-containing afferent nerve fibers are widely distributed in the heart, the relationship between TRPV1 function and cardiac ischemic preconditioning (PC) has not been well defined. Using TRPV1 knockout mice (TRPV1−/−), we studied the role of TRPV1 in PC-induced myocardial protection. Hearts of gene-targeted TRPV1-null mutant (TRPV1−/−) or wild-type (WT) mice were Langendorffly perfused in the presence or absence of CGRP8-37, a selective calcitonin gene-related peptide (CGRP) receptor antagonist; or RP-67580, a selective neurokinin-1 receptor antagonist when hearts were subjected to three 5-min periods of ischemia PC followed by 30 min of global ischemia and 40 min of reperfusion (I/R). PC before I/R decreased left ventricular (LV) end-diastolic pressure and increased LV developed pressure, coronary flow (CF), peak-positive maximum rate of rise of LV pressure in WT mice (PC-WT) compared with PC-TRPV1−/−, TRPV1−/−, or WT hearts ( P < 0.05), and PC also decreased LV end-diastolic pressure in PC-TRPV1−/− compared with TRPV1−/−. CGRP8-37 or RP-67580 abolished PC-induced protection in WT but not TRPV1−/− hearts ( P < 0.05). Moreover, PC decreased lactate dehydrogenase release and infarct size in PC-WT compared with PC-TRPV1−/−, TRPV1−/−, or WT hearts, and it also lowered these parameters in PC-TRPV1−/− compared with TRPV1−/− hearts ( P < 0.05). Radioimmunoassay showed that the release of substance P and CGRP after PC was higher in WT hearts than in TRPV1−/− hearts ( P < 0.05), which was attenuated by capsazepine in WT but not TRPV1−/− hearts. Thus PC-induced protection of the heart was impaired in TRPV1−/− hearts, indicating that TRPV1 contributes to the beneficial effects of preconditioning against I/R injury through release substance P and CGRP.
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Affiliation(s)
- Beihua Zhong
- Department of Medicine, Michigan State University, East Lansing, MI 48824, USA
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455
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Hasdemir B, Bunnett NW, Cottrell GS. Hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) mediates post-endocytic trafficking of protease-activated receptor 2 and calcitonin receptor-like receptor. J Biol Chem 2007; 282:29646-57. [PMID: 17675298 DOI: 10.1074/jbc.m702974200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The E3 ligase c-Cbl ubiquitinates protease-activated receptor 2 (PAR(2)), which is required for post-endocytic sorting of PAR(2) to lysosomes, where degradation arrests signaling. The mechanisms of post-endocytic sorting of ubiquitinated receptors are incompletely understood. Here, we investigated the role of hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), in post-endocytic sorting and signaling of PAR(2). In HEK-PAR(2) cells, PAR(2) activating peptide (PAR(2)-AP) induced PAR(2) trafficking from the cell surface to early endosomes containing endogenous HRS, and then to lysosomes. HRS overexpression or knockdown with small interfering RNA caused formation of enlarged HRS-positive endosomes, where activated PAR(2) and c-Cbl accumulated, and PAR(2) failed to traffic to lysosomes. Overexpression of HRS prevented PAR(2)-AP-induced degradation of PAR(2), as determined by Western blotting. Overexpression of HRS mutant lacking an ubiquitin-binding motif similarly caused retention of PAR(2) in enlarged endosomes. Moreover, HRS overexpression or knockdown caused retention of ubiquitin-resistant PAR(2)Delta14K/R in enlarged HRS-containing endosomes, preventing recycling and resensitization of PAR(2)Delta14K/R. HRS overexpression or knockdown similarly prevented lysosomal trafficking and recycling of calcitonin receptor-like receptor, a non-ubiquitinated receptor that traffics to lysosomes after sustained activation and recycles after transient activation. Thus, HRS plays a critically important role in the post-endocytic sorting of single receptors, PAR(2) and CLR, to both degradative and recycling pathways. This sorting role for HRS is independent of its ubiquitin-interacting motif, and it can regulate trafficking of both ubiquitinated and non-ubiquitinated PAR(2) and non-ubiquitinated CLR. The ultimate sorting decision to degradative or recycling pathways appears to occur downstream from HRS.
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Affiliation(s)
- Burcu Hasdemir
- Department of Surgery, University of California, San Francisco, California 94143-0660, USA
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456
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Lafont AG, Dufour S, Fouchereau-Peron M. Evolution of the CT/CGRP family: comparative study with new data from models of teleosts, the eel, and cephalopod molluscs, the cuttlefish and the nautilus. Gen Comp Endocrinol 2007; 153:155-69. [PMID: 17353015 DOI: 10.1016/j.ygcen.2007.01.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Revised: 01/22/2007] [Accepted: 01/23/2007] [Indexed: 11/20/2022]
Abstract
In mammals, alternative splicing of the calcitonin gene generates two distinct peptides: calcitonin (CT), synthesised in the thyroid C cells and involved in the regulation of calcium metabolism, and calcitonin gene-related peptide (CGRP), brain neuromediator synthesised in the peripheral and central nerves. CGRP is well represented and molecularly conserved during evolution whereas CT has not been detected in any of the invertebrates analysed so far. In order to better understand the evolution of this CT/CGRP peptide family we reviewed the major data concerning its evolution from the literature and our recent data obtained in models of teleosts and cephalopod molluscs. The presence of both CGRP-like molecules and its specific bindings sites in the central nervous system of eel, cuttlefish and nautilus, suggests that the brain neurotransmitter role of CGRP could represent an ancient role in metazoa, already present in cephalopods and conserved among vertebrates, as still observed in mammals. In contrast, the presence of CGRP specific binding sites, and not the peptide itself, in the gills suggests an endocrine role for CGRP, in cephalopods and teleosts, that may have been lost during the evolution of the tetrapod lineage. These data, and the absence of CT-like molecules that we observed in cephalopods, support the hypothesis that CGRP represents the ancestral molecule of the CT/CGRP family, appeared in metazoa before the vertebrate emergence. The distinction between CT and CGRP receptors appears to be an event posterior to the emergence of ecdysozoan and lophotrochozoan protostomes, probably in relation to the CT appearance. The evolution of the CT/CGRP peptide family is probably similar to the evolution of the CT/CGRP receptor family. In fact, the genic duplication that induced the appearance of the two separate molecules, CT and CGRP, may constitute an event close to that, which induced the appearance of the two specific receptors. These events remain to be further studied in order to better understand the peptide and receptor evolution of the CT/CGRP family.
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Affiliation(s)
- Anne-Gaëlle Lafont
- Muséum National d'Histoire Naturelle, Département des Milieux et Peuplements Aquatiques, USM 0401, UMR 5178 CNRS/MNHN/UPMC, Biologie des Organismes Marins et Ecosystèmes, Station de Biologie Marine, 29900 Concarneau, France
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457
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Gonzalez NC, Allen J, Blanco VG, Schmidt EJ, van Rooijen N, Wood JG. Alveolar macrophages are necessary for the systemic inflammation of acute alveolar hypoxia. J Appl Physiol (1985) 2007; 103:1386-94. [PMID: 17656628 DOI: 10.1152/japplphysiol.00312.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alveolar hypoxia (Fi(O(2)) 0.10) rapidly produces inflammation in the microcirculation of skeletal muscle, brain, and mesentery of rats. Dissociation between tissue Po(2) values and inflammation, plus the observation that plasma from hypoxic rats activates mast cells and elicits inflammation in normoxic tissues, suggest that the response to hypoxia is initiated when mast cells are activated by an agent released from a distant site and carried by the circulation. These experiments tested the hypothesis that this agent originates in alveolar macrophages (AM). Male rats were depleted of AM by tracheal instillation of clodronate-containing liposomes. Four days after treatment, AM recovered by bronchoalveolar lavage were <10% of control. Control rats received buffer-containing liposomes. As expected, alveolar hypoxia (Fi(O(2)) 0.10) in control rats increased leukocyte-endothelial adherence, produced degranulation of perivascular mast cells, and increased fluorescent albumin extravasation in the cremaster microcirculation. None of these effects was seen when AM-depleted rats were exposed to hypoxia. Plasma obtained from control rats after 5 min of breathing 10% O(2) elicited inflammation when applied to normoxic cremasters. In contrast, normoxic cremasters did not develop inflammation after application of plasma from hypoxic AM-depleted rats. Supernatant from AM cultured in 10% O(2) produced increased leukocyte-endothelial adherence, vasoconstriction, and albumin extravasation when applied to normoxic cremasters. Normoxic AM supernatant did not produce any of these responses. The effects of hypoxic supernatant were attenuated by pretreatment of the cremaster with the mast cell stabilizer cromolyn. These data support the hypothesis that AM are the source of the agent that initiates hypoxia-induced systemic inflammation by activating mast cells.
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MESH Headings
- Acute Disease
- Animals
- Brain/blood supply
- Cell Adhesion/physiology
- Cells, Cultured
- Clodronic Acid/pharmacology
- Disease Models, Animal
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiology
- Hypoxia/complications
- Hypoxia/metabolism
- Hypoxia/pathology
- Leukocytes/pathology
- Leukocytes/physiology
- Lung Diseases, Interstitial/pathology
- Macrophages, Alveolar/drug effects
- Macrophages, Alveolar/pathology
- Macrophages, Alveolar/physiology
- Male
- Mast Cells/pathology
- Mesentery/blood supply
- Microcirculation/drug effects
- Microcirculation/pathology
- Muscle, Skeletal/blood supply
- Pulmonary Alveoli/drug effects
- Pulmonary Alveoli/pathology
- Rats
- Rats, Sprague-Dawley
- Vasculitis/etiology
- Vasculitis/metabolism
- Vasculitis/pathology
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Affiliation(s)
- Norberto C Gonzalez
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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458
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Martínez-Alvarez O, Guimas L, Delannoy C, Fouchereau-Peron M. Occurrence of a CGRP-like molecule in siki (Centroscymnus coelolepsis) hydrolysate of industrial origin. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:5469-75. [PMID: 17579425 DOI: 10.1021/jf070302l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Fish protein hydrolysates (FPH) may have potential as bioactive components in functional foods as nutraceuticals. This study focused on the identification of calcitonin gene-related peptide (CGRP) molecules in FPH. CGRP is a neuropeptide belonging to the calcitonin/CGRP family and is known as potent arterial and venous vasodilator in humans. Hydrolysates of industrial origin were prepared from siki (Centroscymnus coelolepsis) heads and were analyzed for the presence of CGRP-like molecules using specific radioimmunoassays and radioreceptorassays. The biological activity of the CGRP-related molecules was assessed by their ability to stimulate the adenylate cyclase activity in rat liver membranes. They were finally purified using gel exclusion chromatography and high-performance liquid chromatography (HPLC). These molecules presented a molecular weight around 1500-2500 Da and were obtained with a purification factor of 79. The incorporation of FPH with CGRP-like molecules in functional foods could lead to the development of new useful products for health and nutrition markets.
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Affiliation(s)
- Oscar Martínez-Alvarez
- Muséum National d'Histoire Naturelle USM 405, UMR CNRS/MNHN/UPMC 5178, Station Biologie Marine, BP 225, 29182 Concarneau Cedex, France.
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459
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Al Chawaf A, Xu K, Tan L, Vaccarino FJ, Lovejoy DA, Rotzinger S. Corticotropin-releasing factor (CRF)-induced behaviors are modulated by intravenous administration of teneurin C-terminal associated peptide-1 (TCAP-1). Peptides 2007; 28:1406-15. [PMID: 17644218 DOI: 10.1016/j.peptides.2007.05.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 05/30/2007] [Accepted: 05/31/2007] [Indexed: 12/23/2022]
Abstract
The teneurin C-terminal associated peptides (TCAP) are a recently discovered family of bioactive peptides that can attenuate aspects of the behavioral stress responses of rats. Because TCAP has some structural similarity to the corticotropin-releasing factor (CRF) family of peptides, and modulates elements of the stress response, TCAP may act to modulate CRF actions in vivo. This hypothesis was tested by investigating anxiety-related behaviors in male rats following repeated intravenous (IV) TCAP-1 administration with either an acute intracerebroventricular (ICV) or IV CRF challenge. TCAP-1 alone did not affect behavioral responses significantly, however did significantly affect CRF-regulated behaviors depending on CRF's mode of injection. In both the elevated plus-maze and the open field tests, TCAP-1 had an anxiolytic effect on ICV CRF responses as indicated by decreased stretched-attend postures in the elevated plus maze (p<0.05), and increased center time and center entries in the open field (p<0.05). However, prior TCAP-1 treatment has an anxiogenic effect on the IV CRF-induced behaviors (decreased center entries and total distance in the open field (p<0.05)). TCAP-1's actions are not mediated through acute changes in glucocorticoid levels and may occur via a central action in the brain. A fluorescently (FITC)-labeled TCAP-1 analog was IV-administered to investigate whether IV TCAP-1 has the potential to regulate central mechanisms by crossing the blood-brain barrier. FITC-TCAP-1 was detected in blood vessels and fibers in the brain indicating that uptake into the brain is a possible route for its interaction with CRF and its receptors. Thus, TCAP may modulate CRF-associated behaviors by a direct action in the CNS.
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Affiliation(s)
- Arij Al Chawaf
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.
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460
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Lim SC, Morgenthaler NG, Subramaniam T, Wu YS, Goh SK, Sum CF. The relationship between adrenomedullin, metabolic factors, and vascular function in individuals with type 2 diabetes. Diabetes Care 2007; 30:1513-9. [PMID: 17384335 DOI: 10.2337/dc06-1899] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Subjects with type 2 diabetes are at risk for vascular injury. Several vasoactive factors (e.g., angiotensin) have been implicated. We hypothesize that adrenomedullin, a novel vascoactive factor, is deranged in subjects with type 2 diabetes. RESEARCH DESIGN AND METHODS Using a new immunoluminometric method, plasma midregional proadrenomedullin (MR-proADM) was measured in four groups of Chinese subjects: healthy (n = 100, fasting plasma glucose [FPG] <5.6 mmol/l), impaired fasting glucose (IFG) (n = 60, FPG 5.6-6.9 mmol/l), and diabetic subjects with (n = 100) and without (n = 100) nephropathy. Resting forearm cutaneous microcirculatory perfusion (RCMP) was quantified in vivo using 2-dimensional laser Doppler flowmetry. We investigated the relationship between plasma MR-proADM concentrations, multiple metabolic factors, and vascular function. RESULTS We observed a stepwise increase in MR-proADM among the groups: healthy group mean +/- SD 0.27 +/- 0.09, IFG group 0.29 +/- 0.13, diabetic group 0.42 +/- 0.13, and diabetic nephropathy group 0.81 +/- 0.54 nmol/l (diabetic vs. healthy and IFG groups, P = 0.04; and diabetic nephropathy group vs. all, P < 0.01). Statistical adjustment for sex, age, BMI, and blood pressure did not affect the conclusions. Multiple linear regression analysis revealed that highly sensitive C-reactive protein (beta = 0.11; P = 0.01), insulin resistance index (beta = 0.20; P = 0.001), LDL cholesterol (beta = 0.31; P < 0.001), and adiponectin (beta = 0.33; P < 0.001) were significant predictors of plasma MR-proADM concentrations among nondiabetic individuals. Among subjects with diabetes, plasma MR-proADM concentrations correlated significantly with RCMP (r = 0.43, P = 0.002). CONCLUSIONS Plasma MR-proADM concentration was elevated in subjects with type 2 diabetes. This was further accentuated when nephropathy set in. MR-proADM was related to multiple metabolic factors and basal microcirculatory perfusion. Adrenomedullin might play a role in the pathogenesis of diabetic vasculopathy.
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Affiliation(s)
- Su Chi Lim
- Department of Medicine, Alexandra Hospital, Singapore, Republic of Singapore.
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461
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Geber C, Fondel R, Krämer HH, Rolke R, Treede RD, Sommer C, Birklein F. Psychophysics, Flare, and Neurosecretory Function in Human Pain Models: Capsaicin Versus Electrically Evoked Pain. THE JOURNAL OF PAIN 2007; 8:503-14. [PMID: 17434803 DOI: 10.1016/j.jpain.2007.01.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 12/17/2006] [Accepted: 01/22/2007] [Indexed: 12/25/2022]
Abstract
UNLABELLED Intradermal capsaicin injection (CAP) and electrical current stimulation (ES) are analyzed in respect to patterns and test-retest reliability of pain as well as sensory and neurosecretory changes. In 10 healthy subjects, 2x CAP (50 microg) and 2x ES (5 to 30 mA) were applied to the volar forearm. The time period between 2 identical stimulations was about 4 months. Pain ratings, areas of mechanical hyperalgesia, and allodynia were assessed. The intensity of sensory changes was quantified by using quantitative sensory testing. Neurogenic flare was assessed by using laser Doppler imaging. Calcitonin gene-related peptide (CGRP) release was quantified by dermal microdialysis in combination with an enzyme immunoassay. Time course and peak pain ratings were different between CAP and ES. Test-retest correlation was high (r > or = 0.73). Both models induced primary heat hyperalgesia and primary plus secondary pin-prick hyperalgesia. Allodynia occurred in about half of the subjects. Maximum flare sizes did not differ between CAP and ES, but flare intensities were higher for ES. Test-retest correlation was higher for flare sizes than for flare intensity. A significant CGRP release could only be measured after CAP. The different time courses of pain stimulation (CAP: rapidly decaying pain versus ES: pain plateau) led to different peripheral neurosecretory effects but induced similar central plasticity and hyperalgesia. PERSPECTIVE The present study gives a detailed overview of psychophysical and neurosecretory characteristics induced by noxious stimulation with capsaicin and electrical current. We describe differences, similarities, and reproducibility of these human pain models. These data might help to interpret past and future results of human pain studies using experimental pain.
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Affiliation(s)
- Christian Geber
- Klinik und Poliklinik für Neurologie der Universität Mainz, Germany.
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462
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Kay AB, Ali FR, Heaney LG, Benyahia F, Soh CPC, Renz H, Lee TH, Larché M. Airway expression of calcitonin gene-related peptide in T-cell peptide-induced late asthmatic reactions in atopics. Allergy 2007; 62:495-503. [PMID: 17441790 DOI: 10.1111/j.1398-9995.2007.01342.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The mechanisms of late asthmatic reactions provoked in atopic asthmatics by allergen-derived T-cell peptide epitopes remain unclear. Previous studies showed no changes in airway eosinophils or mast cell products after peptide challenge. In the present study our aim was to measure calcitonin gene-related peptide (CGRP), neurokinin (NK)-A, and substance P (SP) in bronchoalveolar lavage fluid and bronchial biopsies (BB) after inhalation of allergen-derived T-cell peptide epitopes since these neuropeptides (NP) had not previously been evaluated in this chronic asthma model. METHODS Bronchoscopy, with BB and bronchoalveolar lavage (BAL), was performed in 24 cat-allergic subjects 6 h after inhalation of Fel d 1-derived peptides. Neuropeptides were measured in BAL by enzyme-linked immunosorbent assay and CGRP expression in the airways was assessed by immunohistochemistry and confocal microscopy. RESULTS Twelve subjects (termed 'responders') developed isolated late reactions. Calcitonin gene-related peptide, but not NK-A or SP, was significantly elevated in BAL in responders only. Biopsy studies showed that in virtually all responders peptide challenge induced marked increases in CGRP immunoreactivity in bronchial epithelial cells, infiltrating submucosal cells and in association with airway smooth muscle. Double immunostaining indicated that CGRP colocalized predominantly to CD3+/CD4+ and CD68+ submucosal inflammatory cells. CONCLUSION Calcitonin gene-related peptide, a potent vasodilator, is markedly up-regulated in the airways of atopic asthmatics during late-phase reactions provoked by inhalation of allergen-derived T-cell peptides.
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Affiliation(s)
- A B Kay
- Department of Allergy & Clinical Immunology, NHLI Division, Imperial College, London, UK
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463
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Wu M, Komori N, Qin C, Farber JP, Linderoth B, Foreman RD. Roles of peripheral terminals of transient receptor potential vanilloid-1 containing sensory fibers in spinal cord stimulation-induced peripheral vasodilation. Brain Res 2007; 1156:80-92. [PMID: 17540346 PMCID: PMC1995562 DOI: 10.1016/j.brainres.2007.04.065] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 04/16/2007] [Accepted: 04/19/2007] [Indexed: 11/29/2022]
Abstract
BACKGROUND Spinal cord stimulation (SCS) is used to relieve ischemic pain and improve peripheral blood flow in selected patients with peripheral arterial diseases. Our previous studies show that antidromic activation of transient receptor potential vanilloid-1 (TRPV1) containing sensory fibers importantly contributes to SCS-induced vasodilation. OBJECTIVES To determine whether peripheral terminals of TRPV1 containing sensory fibers produces vasodilation that depends upon the release of calcitonin gene-related peptide (CGRP) and nitric oxide (NO) during SCS. METHODS A unipolar ball electrode was placed on the left dorsal column at lumbar spinal cord segments 2-3 in sodium pentobarbital anesthetized, paralyzed and ventilated rats. Cutaneous blood flow from left and right hindpaws was recorded with laser Doppler flow perfusion monitors. SCS was applied through a ball electrode at 30%, 60%, 90% and 300% of motor threshold. Resiniferatoxin (RTX; 2 microg/ml, 100 microl), an ultra potent analog of capsaicin, was injected locally into the left hindpaw to functionally inactivate TRPV-1 containing sensory terminals. In another set of experiments, CGRP(8-37), an antagonist of the CGRP-1 receptor, was injected at 0.06, 0.12 or 0.6 mg/100 microl into the left hindpaw to block CGRP responses; N-omega-nitro-l-arginine methyl ester (L-NAME), a nonselective nitric-oxide synthase (NOS) inhibitor, was injected at 0.02 or 0.2 mg/100 microl into the left hindpaw to block nitric oxide synthesis; (4S)-N-(4-Amino-5[aminoethyl]aminopentyl)-N'-nitroguanidine, TFA, a neuronal NOS inhibitor, was injected at 0.02 or 0.1 mg/100 microl into the left hindpaw to block neuronal nitric oxide synthesis. RESULTS SCS at all intensities produced vasodilation in the left hindpaw, but not in the right. RTX administration attenuated SCS-induced vasodilation at all intensities in the left hindpaw (P<0.05, n=7) compared with responses before RTX. CGRP(8-37) administration attenuated SCS-induced vasodilation in the left hindpaw in a dose dependent manner (linear regression, P<0.05) compared with responses before CGRP(8-37). In addition, L-NAME at a high dose, but not (4S)-N-(4-Amino-5[aminoethyl]aminopentyl)-N'-nitroguanidine, TFA, decreased SCS-induced vasodilation (P<0.05, n=5). CONCLUSION While TRPV1, CGRP and NO are known to be localized in the same nerve terminals, our data indicate that SCS-induced vasodilation depends on CGRP release, but not NO release. NO, released from endothelial cells, may be associated with vascular smooth muscle relaxation and peripheral blood flow increase in response to SCS.
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Affiliation(s)
- Mingyuan Wu
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
| | - Naoka Komori
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
| | - Chao Qin
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
| | - Jay P. Farber
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
| | - Bengt Linderoth
- Department of Clinical neuroscience, Section of Neurosurgery, Karolinska Institute, Stockholm, Sweden
| | - Robert D. Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
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464
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Zhang Z, Winborn CS, Marquez de Prado B, Russo AF. Sensitization of calcitonin gene-related peptide receptors by receptor activity-modifying protein-1 in the trigeminal ganglion. J Neurosci 2007; 27:2693-703. [PMID: 17344407 PMCID: PMC6672495 DOI: 10.1523/jneurosci.4542-06.2007] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The neuropeptide calcitonin gene-related peptide (CGRP) from the trigeminal ganglion has been established as a key player in the pathogenesis of migraine. In this study, we provide evidence that the responsiveness of neuronal CGRP receptors is strongly enhanced in vitro and in vivo by expression of human receptor activity-modifying protein-1 (hRAMP1), an obligatory subunit of the CGRP receptor. We first demonstrated that activation of CGRP receptors on cultured trigeminal ganglion neurons increased endogenous CGRP mRNA levels and promoter activity. The promoter activation was cAMP dependent and blocked by the antagonist BIBN4096BS [1-piperidinecarboxamide, N-[2-[[5-amino-l-[[4-(4-pyridinyl)-l-piperazinyl]carbonyl]pentyl]amino]-1-[(3,5-dibromo-4-hydroxyphenyl)methyl]-2-oxoethyl]-4-(1,4-dihydro-2-oxo-3(2H)-quinazolinyl)], a new antimigraine drug. Gene transfer using an adenoviral hRAMP1 expression vector increased the maximal production of cAMP by 1.8 +/- 0.2-fold and decreased the EC50 to 2.3 +/- 0.8 nM from 9.0 +/- 5.9 nM and 15.6 +/- 5.2 nM in uninfected and control-infected cultures, respectively. To establish whether RAMP1 is limiting in vivo as indicated from the culture studies, a transgenic mouse expressing hRAMP1 in the nervous system was generated. After CGRP injection into the whiskerpad, the hRAMP1 transgenic mice displayed 2.2 +/- 0.2-fold greater plasma extravasation, which is a measure of neurogenic inflammation. These results demonstrate that RAMP1 is functionally rate limiting for CGRP receptor activity in the trigeminal ganglion, which raises the possibility that elevated RAMP1 might sensitize some individuals to CGRP actions in migraine.
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Affiliation(s)
| | | | | | - Andrew F. Russo
- Department of Molecular Physiology and Biophysics, and
- Genetics Program, University of Iowa, Iowa City, Iowa 52242
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465
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Breyne J, Van de Voorde J, Vanheel B. Characterization of the vasorelaxation to methanandamide in rat gastric arteries. Can J Physiol Pharmacol 2007; 84:1121-32. [PMID: 17218976 DOI: 10.1139/y06-058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, the relaxant effect of the cannabinoid methanandamide was explored in rat gastric arteries. Since in some vessels cannabinoids have been shown to release calcitonin gene-related peptide (CGRP) from perivascular nerves, the influence of methanandamide was compared with that of exogenous CGRP. Methanandamide and CGRP elicited concentration-dependent, endothelium-independent relaxations. Methanandamide-induced relaxations were unaffected by the CB1 receptor antagonist AM251, the CB2 receptor antagonists AM630 and SR144528, and combined pre-exposure to AM251 and SR144528. Pre-exposure to O-1918, an antagonist of a novel nonCB1/nonCB2 cannabinoid receptor, did not influence the relaxations to methanandamide. Capsaicin or capsazepine treatment slightly inhibited methanandamide-induced relaxations. Preincubation with 30 mmol/L extracellular K+ or 3 mmol/L TEA had no significant effect on the responses elicited by methanandamide, but reduced CGRP-induced relaxations. Relaxation to 10(-5) mol/L methanandamide was significantly blunted by Bay K8644 and by preincubation with nifedipine. Furthermore, 10(-5) mol/L methanandamide significantly inhibited CaCl2-induced contractions in norepinephrine-stimulated vessels previously depleted of intra- and extracellular Ca2+. Finally, preincubation with 10(-5) mol/L methanandamide almost completely abolished high K+-induced contractions. These findings suggest that the vasorelaxant action of methanandamide in rat gastric arteries is not mediated by stimulation of known cannabinoid receptors and only partly related to stimulation of TRPV1 receptors on perivascular nerves. At high concentrations, methanandamide might induce relaxation by reducing calcium entry into the smooth muscle cells.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Arachidonic Acids/pharmacology
- Arteries/drug effects
- Arteries/metabolism
- Calcitonin Gene-Related Peptide/pharmacology
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Chloride/metabolism
- Dose-Response Relationship, Drug
- Female
- In Vitro Techniques
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Nifedipine/pharmacology
- Potassium/metabolism
- Rats
- Rats, Wistar
- Receptors, Cannabinoid/drug effects
- Stomach/blood supply
- TRPV Cation Channels/drug effects
- Vasodilation/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Joke Breyne
- Department of Physiology and Physiopathology, Ghent University, De Pintelaan 185, B-9000 Ghent, Belgium
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466
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Varela N, Chorny A, Gonzalez-Rey E, Delgado M. Tuning inflammation with anti-inflammatory neuropeptides. Expert Opin Biol Ther 2007; 7:461-78. [PMID: 17373898 DOI: 10.1517/14712598.7.4.461] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The immune system is confronted with the daunting task of defending the organism against invading pathogens while at the same time remaining self-tolerant to the body's own constituents and preserving its integrity. The loss of immune tolerance stemming from an unbalance in pro-inflammatory factors versus anti-inflammatory cytokines, or of autoreactive/inflammatory T helper 1 cells versus regulatory/suppressive T cells, results in the breakdown of immune homeostasis and the subsidiary appearance of exacerbated inflammatory and autoimmune diseases. Some neuropeptides have been shown to have anti-inflammatory properties and to participate in maintaining immune tolerance. Here the authors examine the most recent developments in this field and highlight the effectiveness of using neuropeptides in treating several inflammatory and autoimmune disorders.
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Affiliation(s)
- Nieves Varela
- Instituto de Parasitologia y Biomedicina, Consejo Superior de Investigaciones Cientificas (CSIC), Avd. Conocimiento, PT Ciencias de la Salud, Granada 18100, Spain.
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467
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Go AGG, Chow KHM, Hwang ISS, Tang F. Adrenomedullin and its receptor components in adipose tissues: Differences between white and brown fats and the effects of adrenergic stimulation. Peptides 2007; 28:920-7. [PMID: 17250927 DOI: 10.1016/j.peptides.2006.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 12/06/2006] [Accepted: 12/07/2006] [Indexed: 11/22/2022]
Abstract
Male Sprague-Dawley rats were subcutaneously injected with 2.5mg/kg phenylephrine or 2.5mg/kg isoproterenol or both (2.5mg/kg for each drug) for 4 days, twice a day. Samples of scapular brown adipose tissue (BAT) and epididymal white adipose tissue (WAT) were collected for the measurement of adrenomedullin (AM) levels and the gene expression of preproAM, calcitonin receptor like receptor (CRLR) and its activity modifying proteins (RAMPs) by radioimmunoassay and RT-PCR. These values were compared with those in the rats that received 0.9% saline. The gene expression of AM and AM receptor components in BAT are much less than that in epididymal WAT. In BAT there were an increase in AM peptide level after a combined treatment of alpha(1) and beta adrenoceptor agonists and increases in preproAM mRNA levels for rats treated with alpha(1) and beta receptor agonists alone or in combination. Both CRLR and RAMP2 mRNA levels of alphabeta group were increased significantly. In WAT, AM peptide level, RAMP1 and RAMP2 mRNA expression levels were augmented in the alpha group while CRLR mRNA level was enhanced in the beta group. The levels of AM, its receptor and RAMPs are much less in BAT than in WAT but adrenergic stimulation has a greater effect on the AM and its receptor components in BAT than those in WAT. AM stimulates lipolysis and increases the level of uncoupling protein-1 (UCP-1) in BAT. It may therefore enhance thermogenesis by increasing the availability of free fatty acids substrate as well as the UCP-1 level on the mitochondrial membrane.
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MESH Headings
- Adipose Tissue, Brown/chemistry
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, White/chemistry
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Adrenergic Agents/administration & dosage
- Adrenergic Agents/pharmacology
- Adrenomedullin/genetics
- Adrenomedullin/metabolism
- Animals
- Blotting, Western
- Body Weight/drug effects
- Calcitonin Receptor-Like Protein
- Gene Expression Regulation/drug effects
- Injections, Subcutaneous
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Ion Channels/metabolism
- Isoproterenol/administration & dosage
- Isoproterenol/pharmacology
- Lipolysis/drug effects
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mitochondrial Proteins/metabolism
- Phenylephrine/administration & dosage
- Phenylephrine/pharmacology
- Protein Precursors/genetics
- Protein Precursors/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Radioimmunoassay
- Rats
- Rats, Sprague-Dawley
- Receptor Activity-Modifying Proteins
- Receptors, Adrenomedullin
- Receptors, Calcitonin/genetics
- Receptors, Calcitonin/metabolism
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Uncoupling Protein 1
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Affiliation(s)
- Adi G G Go
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
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468
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Rossi M, Carpi A, Di Maria C, Galetta F, Santoro G. Skin microcirculatory effect of exogenous calcitonin gene-related peptide (CGRP) evaluated by laser Doppler flowmetry coupled with iontophoresis in healthy subjects. Microvasc Res 2007; 73:124-30. [PMID: 17188310 DOI: 10.1016/j.mvr.2006.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 10/26/2006] [Accepted: 10/26/2006] [Indexed: 11/25/2022]
Abstract
The aim of our study was to evaluate the feasibility of laser Doppler flowmetry (LDF) coupled with iontophoresis in exploring the skin vasodilator activity of exogenous calcitonin gene-related peptide (CGRP) in healthy subjects and to investigate the mechanisms involved in the skin vasodilator activity of this peptide. Forearm skin blood perfusion was measured in conventional perfusion unit (PU; 1 PU=10 mV), using a LDF apparatus (Periflux PF4001, Perimed, Sweden), before and following exogenous CGRP dissolved in distilled water (0.02%) or pure saline iontophoresis. Different iontophoresis protocols were used in a preliminary dose finding study in six subjects. Two pulses (0.1 mA for 30 s each) of anodal CGRP or saline iontophoresis were used in the definitive study in 20 subjects. Power spectral density (PSD) of skin blood flowmotion frequency intervals (FI), related to endothelial (0.009-0.02 Hz), sympathetic (0.02-0.06 Hz), myogenic (0.06-0.2 Hz), respiratory (0.2-0.6 Hz) and heart (0.6-1.6 Hz) activities, was also measured in PU(2)/Hz, by means of spectral analysis of the skin LDF signal registered before and following iontophoresis of CGRP or saline in the definitive study. A significantly higher per cent increase in skin perfusion compared to baseline was observed following CGRP than saline iontophoresis (548+/-369% vs. 326+/-192%, p<0.05), with higher hyperaemic response to pure saline than CGRP iontophoresis in only five subjects. A significant increase (p<0.05) in PSD mean value of the five FI considered, was also observed following CGRP iontophoresis, while saline iontophoresis elicited a significant increase (p<0.05) only in PSD of the FI related to endothelial, respiratory and heart activity. These findings demonstrated that LDF coupled with iontophoresis is a feasible method in evaluating the vasodilator effect of exogenous CGRP in human skin and suggest that this peptide directly or indirectly induces a smooth muscle vascular cells and sympathetic fibres stimulation.
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Affiliation(s)
- M Rossi
- Department of Internal Medicine, University of Pisa, Italy.
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469
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Caron K, Hagaman J, Nishikimi T, Kim HS, Smithies O. Adrenomedullin gene expression differences in mice do not affect blood pressure but modulate hypertension-induced pathology in males. Proc Natl Acad Sci U S A 2007; 104:3420-5. [PMID: 17360661 PMCID: PMC1802008 DOI: 10.1073/pnas.0611365104] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adrenomedullin (AM) is a potent vasodilator peptide in plasma at picomolar levels. Polymorphisms in the human AM gene have been associated with genetic predisposition to diabetic nephropathy and proteinuria with essential hypertension, and numerous studies have demonstrated that endogenous AM plays a role in protecting the heart and kidneys from fibrosis resulting from cardiovascular disease. Elevated plasma levels of AM are associated with pregnancy and sepsis and with cardiovascular stress and hypertension. However, there are no reports of the effects of genetic differences in the expression of the endogenous AM gene and of gender on blood pressure in these circumstances or on the pathological changes accompanying hypertension. To address these questions, we have generated mice having genetically controlled levels of AM mRNA ranging from approximately 50% to approximately 140% of wild-type levels. These modest changes in AM gene expression have no effect on basal blood pressure. Although pregnancy and sepsis increase plasma AM levels, genetically reducing AM production does not affect the transient hypotension that occurs during normal pregnancy or that is induced by treatment with lipopolysaccharide. Nor does the reduction of AM affect chronic hypertension caused by a renin transgene. However, 50% normal expression of AM enhances cardiac hypertrophy and renal damage in male, but not female, mice with a renin transgene. These observations suggest that the effect of gender on the role of AM in counteracting cardiovascular damage in humans merits careful evaluation.
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Affiliation(s)
- Kathleen Caron
- Department of Cell and Molecular Physiology and Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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470
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Cottrell GS, Padilla B, Pikios S, Roosterman D, Steinhoff M, Grady EF, Bunnett NW. Post-endocytic sorting of calcitonin receptor-like receptor and receptor activity-modifying protein 1. J Biol Chem 2007; 282:12260-71. [PMID: 17310067 DOI: 10.1074/jbc.m606338200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Calcitonin receptor-like receptor (CLR) and the receptor activity-modifying protein 1 (RAMP1) comprise a receptor for calcitonin gene-related peptide (CGRP). Although CGRP induces endocytosis of CLR/RAMP1, little is known about post-endocytic sorting of these proteins. We observed that the duration of stimulation with CGRP markedly affected post-endocytic sorting of CLR/RAMP1. In HEK and SK-N-MC cells, transient stimulation (10(-7) M CGRP, 1 h), induced CLR/RAMP1 recycling with similar kinetics (2-6 h), demonstrated by labeling receptors in living cells with antibodies to extracellular epitopes. Recycling of CLR/RAMP1 correlated with resensitization of CGRP-induced increases in [Ca(2+)](i). Cycloheximide did not affect resensitization, but bafilomycin A(1), an inhibitor of vacuolar H(+)-ATPases, abolished resensitization. Recycling CLR and RAMP1 were detected in endosomes containing Rab4a and Rab11a, and expression of GTPase-defective Rab4aS22N and Rab11aS25N inhibited resensitization. After sustained stimulation (10(-7) M CGRP, >2 h), CLR/RAMP1 trafficked to lysosomes. RAMP1 was degraded approximately 4-fold more rapidly than CLR (RAMP1, 45% degradation, 5 h; CLR, 54% degradation, 16 h), determined by Western blotting. Inhibitors of lysosomal, but not proteasomal, proteases prevented degradation. Sustained stimulation did not induce detectable mono- or polyubiquitination of CLR or RAMP1, determined by immunoprecipitation and Western blotting. Moreover, a RAMP1 mutant lacking the only intracellular lysine (RAMP1K142R) internalized and was degraded normally. Thus, after transient stimulation with CGRP, CLR and RAMP1 traffic from endosomes to the plasma membrane, which mediates resensitization. After sustained stimulation, CLR and RAMP1 traffic from endosomes to lysosomes by ubiquitin-independent mechanisms, where they are degraded at different rates.
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Affiliation(s)
- Graeme S Cottrell
- Department of Surgery, University of California, San Francisco, California 94143-0660, USA
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471
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Dschietzig T, Richter C, Asswad L, Baumann G, Stangl K. Hypoxic induction of receptor activity-modifying protein 2 alters regulation of pulmonary endothelin-1 by adrenomedullin: induction under normoxia versus inhibition under hypoxia. J Pharmacol Exp Ther 2007; 321:409-19. [PMID: 17251392 DOI: 10.1124/jpet.106.114298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The vasodilator adrenomedullin (AM) is up-regulated in pulmonary hypertension, and inhaled AM is beneficial in patients. Therefore, we investigated the effects of AM on pulmonary endothelin-1 (ET-1). In normoxic isolated rat lungs (IRL) and rat pulmonary artery endothelial cells (RPAEC), the calcitonin gene-related peptide type-1 receptor (CGRP1R) antagonist human (h)CGRP(8-37) decreased ET-1 secretion, and the AM receptor antagonist hAM(22-52) had no effect. Exogenous AM (1 and 10 pM) increased ET-1 levels, which was abolished by hCGRP(8-37) and protein kinase A (PKA) inhibition. At 50 and 100 pM, AM decreased ET-1, an effect sensitive to hAM(22-52), NO inhibition, and protein kinase G (PKG) inhibition. In RPAEC, these results were attributed to altered ET-1 gene expression; low exogenous AM also promoted activity of endothelin-converting enzyme, and high AM increased the number of endothelin type-B (ETB) receptor sites. Hypoxia significantly elevated AM and ET-1 levels in IRL and RPAEC, and hAM(22-52), NO inhibition, or PKG inhibitors caused a further ET-1 rise. These interventions also prevented the hypoxia-related increase in ETB sites in RPAEC. In RPAEC, both high AM and hypoxia down-regulated receptor activity-modifying protein (RAMP)1, but they up-regulated RAMP2 protein and AM receptor sites, and RAMP2 silencing by small interference RNA proved its pivotal role for signal switching. In conclusion, endogenous pulmonary AM up-regulates ET-1 and endothelin-converting enzyme activity under physiological conditions, via CGRP1R and PKA. In contrast, hypoxia-induced high AM levels, via AM1 receptor and NO/PKG, down-regulate ET-1 gene expression and promote expression of ETB receptors. This hypoxia-related switch of AM signaling can be attributed to up-regulation of the RAMP2/AM1 receptor system.
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Affiliation(s)
- Thomas Dschietzig
- Department of Cardiology and Angiology, University Medical Centre Charité, Campus Mitte, Schumannstr. 20/21, 10117 Berlin, Germany.
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472
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Abstract
Neuropeptides and kinins are important messengers in the nervous system and--on the basis of their anatomical localisation and the effects produced when the substances themselves are administered, to animals or to human subjects-a significant number of them have been suggested to have a role in pain and inflammation. Experiments in gene deletion (knock-out or null mutant) mice and parallel experiments with pharmacological receptor antagonists in a variety of species have strengthened the evidence that a number of peptides, notably substance P and calcitonin gene-related peptide (CGRP), and the kinins have a pathophysiological role in nociception. Clinical studies with non-peptide pharmacological antagonists are now in progress to determine if blocking the action of these peptides might have utility in the treatment of pain.
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Affiliation(s)
- R G Hill
- Merck, Sharp and Dohme Research Laboratories, Terlings Park, Harlow, Essex CM20 2QR, UK.
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473
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Brain SD, Cox HM. Neuropeptides and their receptors: innovative science providing novel therapeutic targets. Br J Pharmacol 2006; 147 Suppl 1:S202-11. [PMID: 16402106 PMCID: PMC1760747 DOI: 10.1038/sj.bjp.0706461] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This review examines our current understanding of the roles of some of the best known neuropeptides that have played major roles in our combined research programmes. Evidence obtained from over 75 years of research shows involvement of these transmitters in a wide range of organs relevant to cardiovascular, respiratory, cutaneous, neuronal and intestinal systems. There is an increasing understanding of the mechanisms involved in the release of the peptides (substance P and calcitonin gene-related peptide (CGRP)) from sensory nerves or, neuropeptide Y (NPY) from sympathetic, parasympathetic and nonadrenergic, noncholinergic (NANC) neurons. Responses in target tissues result from interactions of the neuropeptides, or related forms, with specific G-protein coupled receptors (GPCRs or 7 transmembrane-spanning, 7TM proteins) that belong to either rhodopsin-like, class 1 (neurokinin (NK) and NPY Y receptors) or secretin-like, class 2 GPCRs (CGRP receptors). The majority of receptors activated by our chosen neuropeptides are now cloned, with knowledge of preferred agonists and selective antagonists for many receptor subtypes within these families. The study of neuropeptides in animal models has additionally revealed physiological and pathophysiological roles that in turn have led to the ongoing development of new drugs, through utilization predominantly of antagonist activities.
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Affiliation(s)
- Susan D Brain
- King's College London, Cardiovascular Division, School of Biomedical and Health Sciences, New Hunt's House, Guy's Campus, London SE1 1UL.
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474
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Petkov V, Baykuscheva-Gentscheva T, Hoeger H, Painsipp E, Holzer P, Mosgoeller W. Involvement of endothelial NO in the dilator effect of VIP on rat isolated pulmonary artery. ACTA ACUST UNITED AC 2006; 139:102-8. [PMID: 17174416 DOI: 10.1016/j.regpep.2006.10.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 10/18/2006] [Indexed: 11/25/2022]
Abstract
The endothelium and its interaction with smooth muscle play a central role in the local control of the pulmonary vasculature, and endothelial dysfunction is thought to contribute to pulmonary hypertension and chronic obstructive pulmonary disease. Vasoactive intestinal peptide (VIP), a 28-amino acid neuropeptide, relaxes the rat pulmonary artery, but there is controversy as to whether or not this action of VIP depends on the endothelium. The aim of this study, therefore, was to investigate the role of the endothelium and nitric oxide (NO), the major endothelium-derived relaxing factor, in the dilator action of VIP on the rat isolated pulmonary artery. Pulmonary artery preparations pre-contracted by the alpha(1)-adrenoceptor agonist L-phenylephrine were relaxed by VIP (0.003-1 microM) and acetylcholine (0.003-10 microM) in a concentration-dependent manner. Mechanical removal of the endothelium reduced the maximal response to VIP by about 50% and practically abolished the response to acetylcholine. Inhibition of NO synthesis by N(omega)-nitro-L-arginine methyl ester (0.5 mM) had a similar effect, abolishing the vasorelaxation caused by acetylcholine and attenuating the vasorelaxation caused by VIP by about 50%. From these data it is concluded that the relaxant action of VIP on the rat isolated pulmonary artery depends in part on the presence of the endothelium and that this part is mediated by endothelial NO.
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475
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Ogoshi M, Inoue K, Naruse K, Takei Y. Evolutionary history of the calcitonin gene-related peptide family in vertebrates revealed by comparative genomic analyses. Peptides 2006; 27:3154-64. [PMID: 17092606 DOI: 10.1016/j.peptides.2006.09.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 09/20/2006] [Accepted: 09/25/2006] [Indexed: 11/29/2022]
Abstract
The calcitonin gene-related peptide (CGRP) family is composed of CGRP, amylin and adrenomedullin (AM) in mammals. In teleost fish, AM forms an independent subfamily of five members (AM1-5), which inspired us to trace the evolutionary history of the CGRP family throughout vertebrates by comparative genomic approach. Linkage mapping and synteny analyses of the CGRP family genes in medaka, Oryzias latipes, revealed that AM1/CGRP, AM2/amylin, and AM5 genes were located on respective proto-chromosomes before the divergence of teleost lineage. In teleost fish, additional whole genome duplication generated AM1/4, CGRP1/2, AM2/3, but one of the duplicated amylin and AM5 genes was silenced. In mammals, the amylin or AM2 gene was translocated to different chromosomes, while the CGRP gene was multiplied in tandem to generate CGRP-alpha,beta, and recently identified calcitonin receptor-stimulating peptide genes. Based on these data, we identified a novel AM5 gene in several mammalian species as we previously did for AM2.
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Affiliation(s)
- Maho Ogoshi
- Ocean Research Institute, University of Tokyo, Nakano, Tokyo 164-8639, Japan.
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476
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Fujisawa Y, Nagai Y, Miyatake A, Miura K, Nishiyama A, Kimura S, Abe Y. Effects of adrenomedullin 2 on regional hemodynamics in conscious rats. Eur J Pharmacol 2006; 558:128-32. [PMID: 17204266 DOI: 10.1016/j.ejphar.2006.11.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 11/10/2006] [Accepted: 11/21/2006] [Indexed: 11/25/2022]
Abstract
The present study aimed to assess the effects of rat adrenomedullin 2 on systemic and regional hemodynamics in conscious Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). Intravenous infusion of rat adrenomedullin 2 (0.25-5 micro g/kg/min) decreased blood pressure, and increased heart rate in a dose-dependent manner in both types of rats. Rat adrenomedullin 2 (5 micro g/kg/min) increased heart rate and cardiac output. As a result, total peripheral resistance significantly decreased. In SHRs, adrenomedullin 2 significantly increased regional blood flow in the heart, liver, spleen, kidneys, and adrenal glands. Especially, effects on heart, liver, and kidneys were remarkable. Regional hemodynamic changes were reproduced in WKY rats, and there was no qualitative difference in regional responses to rat adrenomedullin 2 between SHRs and WKY rats. Thus, rat adrenomedullin 2 predominantly increased flow rates in organs that were richly blood-supplied from cardiac output. Rat adrenomedullin 2 may contribute to the regulation of the cardiovascular system, by acting as a local vasodilatory hormone as well as a circulatory hormone.
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Affiliation(s)
- Yoshihide Fujisawa
- Life Science Center, School of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-Gun, Kagawa, Japan.
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477
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Hu DE, Easton AS, Fraser PA. TRPV1 activation results in disruption of the blood-brain barrier in the rat. Br J Pharmacol 2006; 146:576-84. [PMID: 16056236 PMCID: PMC1751183 DOI: 10.1038/sj.bjp.0706350] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We have examined the role of TRPV1 activation in disrupting the blood-brain barrier by measuring the permeability of single pial venular capillaries in anaesthetized rats. Capsaicin application to the brain surface resulted in increased permeability, maximal 2.1+/-0.12 x 10(-6) cm s(-1) (mean+/-s.e.m.) with log EC50 -4.5+/-0.10. Substance P methyl ester gave a similar response (maximal 2.0+/-0.07, n = 6, log EC50 -4.8+/-0.07), but the selective NK2 agonist, beta-Ala8-NKA(4-10) peptide, had no effect. Although CGRP decreased the permeability of venules (log EC50 10.3+/-0.11), its receptor antagonist CGRP(8-37) had no effect on the response to capsaicin. The TRPV1 antagonist capsazepine (1 mM) reduced the response to capsaicin (100 microM), from 1.78+/-0.15 to 0.63+/-0.10 (n = 4). The NK1 receptor antagonists GR205171 (100 microM) and SDZ NKT 376 (1 mM) also reduced the response to capsaicin (from 1.75+/-0.14 to 0.46+/-0.08; n = 6, and from 1.85+/-0.13 to 0.48+/-0.05; n = 5, respectively), indicating that capsaicin acts via TRPV1 in series with NK(1). Starch microspheres were used to produce transient focal ischaemia. Permeability was increased on reperfusion to a greater extent and more rapidly in vessels with diameter greater than 40 microm than those less than 15 microm. Capsazepine given intraperitoneally during ischaemia reduced the permeability increase in small venules from 5.9+/-0.3 to 2.4+/-0.1, and from 11.4+/-0.8 to 5.1+/-0.9 in large venules. In conclusion, the TRPV1 receptor is active in the brain microvasculature and has its permeability-increasing effect via substance P. It also plays a role in the immediate blood-brain barrier disruption following ischaemia-reperfusion.
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Affiliation(s)
- De-En Hu
- King's College London, Cardiovascular Division, New Hunt's House, Guy's Campus, London SE1 1UL
| | - Alexander S Easton
- King's College London, Cardiovascular Division, New Hunt's House, Guy's Campus, London SE1 1UL
| | - Paul A Fraser
- King's College London, Cardiovascular Division, New Hunt's House, Guy's Campus, London SE1 1UL
- Author for correspondence:
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478
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Hagner S, Stahl U, Grimm T, Stürzl M, Lang RE. Expression of calcitonin receptor-like receptor in human vascular tumours. J Clin Pathol 2006; 59:1104-7. [PMID: 17021138 PMCID: PMC1861761 DOI: 10.1136/jcp.2005.026930] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Vascular tumours such as Kaposi's sarcoma and capillary haemangioma are characterised by abnormal vascularisation and proliferation of endothelial cells or neoplastic cells. Adrenomedullin, a potent vasodilative peptide, and its receptor, calcitonin receptor-like receptor (CRLR), play an important part in angiogenesis. AIM To establish whether this system also plays a part in vascular diseases, showing abnormal proliferation such as vascular tumours. METHODS CRLR expression was investigated in several specimens of Kaposi's sarcoma and other vascular tumours, using immunohistochemical analysis with a previously described CRLR-specific polyclonal antibody and reverse transcriptase-polymerase chain reaction. RESULTS Intense and specific CRLR-immunoreactive staining of neoplastic cells was observed in all specimens, which was of greater intensity than similar staining of adjacent normal endothelium. CONCLUSIONS CRLR is expressed in vascular tumours and, with adrenomedullin, may have a role in neoplastic vascular growth.
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Affiliation(s)
- S Hagner
- Institute of Physiology, Philipps-University Marburg, Marburg, Germany.
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479
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Rossi F, Bertone C, Petricca S, Santiemma V. Adrenomedullin antagonizes angiotensin II-stimulated proliferation of human aortic smooth muscle cells. Peptides 2006; 27:2935-41. [PMID: 16797107 DOI: 10.1016/j.peptides.2006.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Revised: 05/11/2006] [Accepted: 05/11/2006] [Indexed: 11/30/2022]
Abstract
The vasodilating peptide adrenomedullin has been reported to regulate vascular tone as well as proliferation and differentiation of various cell types in an autocrine/paracrine manner. Conflicting data have been reported on the adrenomedullin (AM) effect on vascular smooth muscle cell proliferation, a process involved in the progression of vascular remodeling and atherosclerotic lesion. In this paper we investigate the effect of AM on proliferation of human aorta smooth muscle cell (HASMC). AM showed a potent dose-dependent inhibiting effect on angiotensin II (AngII) induced-proliferation and a stimulatory effect on proliferation of quiescent cells. The cAMP/PKA pathway was involved in the AM inhibitory effect of AngII-induced proliferation in HASMC. PI3K/Akt and ERK pathways were involved in the proliferative effect exerted by AM per se. Our results suggest that AM plays a role in the regulation of HASMC growth antagonizing the AngII effect and may be involved in conditions of altered regulation of the blood vessels.
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Affiliation(s)
- Fabio Rossi
- Dipartimento di Fisiopatologia Medica, V Clinica Medica, Università La Sapienza, Facoltà di Medicina, Policlinico Umberto I, Viale del Policlinico, 00161 Rome, Italy
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480
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Gibbons C, Dackor R, Dunworth W, Fritz-Six K, Caron KM. Receptor activity-modifying proteins: RAMPing up adrenomedullin signaling. Mol Endocrinol 2006; 21:783-96. [PMID: 17053041 DOI: 10.1210/me.2006-0156] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Adrenomedullin (AM) is a 52-amino-acid multifunctional peptide that circulates in the plasma in the low picomolar range and can exert a multitude of biological effects through an autocrine/paracrine mode of action. The mechanism by which AM transduces its signal represents a novel and pharmacologically tractable paradigm in G protein-coupled receptor signaling. Since its discovery in 1993, the study of AM has emerged into a new field of research with nearly 1800 publications that rivals the renown of other common factors like angiopoetin (1015 publications) and ghrelin (1550 publications). Despite the tremendous strides made in recent years toward unveiling the biochemical and cellular functions of AM, we are still lagging in our understanding of the essential roles of AM in normal and disease physiology. As discussed in this current review, a concerted effort to combine information from clinical, genomic, biochemical, and genetic mouse model sources can provide a focused view to help define the physiological functions of AM. Specifically, we find that certain conditions, such as pregnancy, cardiovascular disease, and sepsis, are associated with robust and dynamic changes in the expression of AM and AM receptor proteins, which together represent an elegant mechanism for altering the physiological responsiveness or function of AM. Thus, the modulation of AM signaling may be further exploited for therapeutic strategies in the management and treatment of human disease.
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Affiliation(s)
- Carrie Gibbons
- Department of Cell and Molecular Physiology, CB # 7545, 6340B MBRB, 103 Mason Farm Road, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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481
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Takei Y, Kawakoshi A, Tsukada T, Yuge S, Ogoshi M, Inoue K, Hyodo S, Bannai H, Miyano S. Contribution of comparative fish studies to general endocrinology: structure and function of some osmoregulatory hormones. ACTA ACUST UNITED AC 2006; 305:787-98. [PMID: 16902950 DOI: 10.1002/jez.a.309] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fish endocrinologists are commonly motivated to pursue their research driven by their own interests in these aquatic animals. However, the data obtained in fish studies not only satisfy their own interests but often contribute more generally to the studies of other vertebrates, including mammals. The life of fishes is characterized by the aquatic habitat, which demands many physiological adjustments distinct from the terrestrial life. Among them, body fluid regulation is of particular importance as the body fluids are exposed to media of varying salinities only across the thin respiratory epithelia of the gills. Endocrine systems play pivotal roles in the homeostatic control of body fluid balance. Judging from the habitat-dependent control mechanisms, some osmoregulatory hormones of fish should have undergone functional and molecular evolution during the ecological transition to the terrestrial life. In fact, water-regulating hormones such as vasopressin are essential for survival on the land, whereas ion-regulating hormones such as natriuretic peptides, guanylins and adrenomedullins are diversified and exhibit more critical functions in aquatic species. In this short review, we introduce some examples illustrating how comparative fish studies contribute to general endocrinology by taking advantage of such differences between fishes and tetrapods. In a functional context, fish studies often afford a deeper understanding of the essential actions of a hormone across vertebrate taxa. Using the natriuretic peptide family as an example, we suggest that more functional studies on fishes will bring similar rewards of understanding. At the molecular level, recent establishment of genome databases in fishes and mammals brings clues to the evolutionary history of hormone molecules via a comparative genomic approach. Because of the functional and molecular diversification of ion-regulating hormones in fishes, this approach sometimes leads to the discovery of new hormones in tetrapods as exemplified by adrenomedullin 2.
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Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Ocean Research Institute, University of Tokyo, Nakano-ku, Tokyo 164-8639, Japan.
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482
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Ma W, Chabot JG, Quirion R. A role for adrenomedullin as a pain-related peptide in the rat. Proc Natl Acad Sci U S A 2006; 103:16027-32. [PMID: 17043245 PMCID: PMC1635121 DOI: 10.1073/pnas.0602488103] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adrenomedullin (AM) belongs to the calcitonin gene-related peptide (CGRP) family and is a well known potent vasodilator. We show here that AM is a powerful pain-inducing neuropeptide. AM-like immunoreactivity is widely distributed in both CGRP-containing and lectin IB4-binding nociceptors in dorsal root ganglion and axon terminals in the superficial dorsal horn of the rat spinal cord. Specific binding sites for the radioligand, [(125)I]AM13-52 as well as immunoreactivity for receptor markers such as the calcitonin receptor-like receptor and three receptor-activity-modifying proteins are localized in the superficial dorsal horn, demonstrating the existence of AM/CGRP receptors in this region. Intrathecal injection of rat AM1-50, dose- and time-dependently, induced long-lasting heat hyperalgesia and increased the phosphorylation of Akt and GSK3beta in the dorsal horn. Pre- and posttreatments with the AM receptor antagonist AM22-52 and PI3 kinase inhibitors (LY294002 and Wortmannin) significantly blocked or reversed AM-induced heat hyperalgesia. Pre- and posttreatments with AM22-52 and Wortmannin also significantly blocked or reversed intraplantar capsaicin-induced heat hyperalgesia. Taken together, our results demonstrate that AM acts as a pain-inducing peptide in the dorsal horn. By activating specific receptors (likely AM2) and the PI3K/Akt/GSK3beta signaling pathway, AM could play a significant role in long-lasting heat hypersensitivity and inflammatory heat hyperalgesia.
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Affiliation(s)
- Weiya Ma
- *Douglas Hospital Research Center, and
| | | | - Remi Quirion
- *Douglas Hospital Research Center, and
- Department of Psychiatry, McGill University, Montreal, QC, Canada H4H 1R3
- To whom correspondence should be addressed. E-mail:
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483
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Roosterman D, Goerge T, Schneider SW, Bunnett NW, Steinhoff M. Neuronal Control of Skin Function: The Skin as a Neuroimmunoendocrine Organ. Physiol Rev 2006; 86:1309-79. [PMID: 17015491 DOI: 10.1152/physrev.00026.2005] [Citation(s) in RCA: 405] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
This review focuses on the role of the peripheral nervous system in cutaneous biology and disease. During the last few years, a modern concept of an interactive network between cutaneous nerves, the neuroendocrine axis, and the immune system has been established. We learned that neurocutaneous interactions influence a variety of physiological and pathophysiological functions, including cell growth, immunity, inflammation, pruritus, and wound healing. This interaction is mediated by primary afferent as well as autonomic nerves, which release neuromediators and activate specific receptors on many target cells in the skin. A dense network of sensory nerves releases neuropeptides, thereby modulating inflammation, cell growth, and the immune responses in the skin. Neurotrophic factors, in addition to regulating nerve growth, participate in many properties of skin function. The skin expresses a variety of neurohormone receptors coupled to heterotrimeric G proteins that are tightly involved in skin homeostasis and inflammation. This neurohormone-receptor interaction is modulated by endopeptidases, which are able to terminate neuropeptide-induced inflammatory or immune responses. Neuronal proteinase-activated receptors or transient receptor potential ion channels are recently described receptors that may have been important in regulating neurogenic inflammation, pain, and pruritus. Together, a close multidirectional interaction between neuromediators, high-affinity receptors, and regulatory proteases is critically involved to maintain tissue integrity and regulate inflammatory responses in the skin. A deeper understanding of cutaneous neuroimmunoendocrinology may help to develop new strategies for the treatment of several skin diseases.
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484
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Peters EMJ, Ericson ME, Hosoi J, Seiffert K, Hordinsky MK, Ansel JC, Paus R, Scholzen TE. Neuropeptide control mechanisms in cutaneous biology: physiological and clinical significance. J Invest Dermatol 2006; 126:1937-47. [PMID: 16912691 DOI: 10.1038/sj.jid.5700429] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The skin as a barrier and immune organ is exposed to omnipresent environmental challenges such as irradiation or chemical and biologic hazards. Neuropeptides released from cutaneous nerves or skin and immune cells in response to noxious stimuli are mandatory for a fine-tuned regulation of cutaneous immune responses and tissue maintenance and repair. They initialize host immune responses, but are equally important for counter regulation of proinflammatory events. Interaction of the nervous and immune systems occurs both locally - at the level of neurogenic inflammation and immunocyte activation - and centrally - by controlling inflammatory pathways such as mononuclear activation or lymphocyte cytokine secretion. Consequently, a deregulated neurogenic immune control results in disease manifestation and frequently accompanies chronic development of cutaneous disorders. The current understanding, therapeutic options, and open questions of the role that neuropeptides such as substance P, calcitonin gene-related peptide, vasoactive intestinal peptide/pituitary adenylate cyclase-activating polypeptide, neuropeptide Y, or others play in these events are discussed. Progress in this field will likely result in novel therapies for the management of diseases characterized by deregulated inflammation, tissue remodeling, angiogenesis, and neoplasm.
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Affiliation(s)
- Eva M J Peters
- Department of Internal Medicine, Psychosomatics, Biomedical Research Center, Universitätsmedizin-Charité, Campus Virchow Klinikum, Berlin, Germany.
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485
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Márquez-Rodas I, Longo F, Rothlin RP, Balfagón G. Pathophysiology and therapeutic possibilities of calcitonin gene-related peptide in hypertension. J Physiol Biochem 2006; 62:45-56. [PMID: 16909931 DOI: 10.1007/bf03165805] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Calcitonin gene related peptide (CGRP), a 37 amino acid neuropeptide, is the most potent vasodilator known. Participation of CGRP in hypertension and related diseases, such as preeclampsia or vasospasm after subarachnoid haemorrage, is one of the most studied topics. In this review we summarize the published roles of CGRP in pathophysiology of hypertension in humans and in experimental models. We also discuss the effects of direct administration of CGRP in the treatment of hypertension and of anti-hypertensive drugs that enhance the release or response of endogenous calcitonin gene-related peptide: angiotensin converting enzyme inhibitors, selective antagonists for the angiotensin II receptor, beta-blockers, magnesium sulphate for preeclampsia and rutaecarpine, as well as the possibilities using CGRP in gene therapy for prevention of vasospasm after subarachnoid haemorrage.
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Affiliation(s)
- I Márquez-Rodas
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo 4, 28029 Madrid, Spain. and 1II1 Citedra de Farmacologfa, Facultad de Medicina, Universidad de Buenos Aires
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486
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Hay DL, Christopoulos G, Christopoulos A, Sexton PM. Determinants of 1-Piperidinecarboxamide, N-[2-[[5-Amino-l-[[4-(4-pyridinyl)-l-piperazinyl]carbonyl]pentyl]amino]-1-[(3,5-dibromo-4-hydroxyphenyl)methyl]-2-oxoethyl]-4-(1,4-dihydro-2-oxo-3(2H)-quinazolinyl) (BIBN4096BS) Affinity for Calcitonin Gene-Related Peptide and Amylin Receptors—The Role of Receptor Activity Modifying Protein 1. Mol Pharmacol 2006; 70:1984-91. [PMID: 16959943 DOI: 10.1124/mol.106.027953] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
1-Piperidinecarboxamide, N-[2-[[5-amino-l-[[4-(4-pyridinyl)-l-piperazinyl]carbonyl]pentyl]amino]-1-[(3,5-dibromo-4-hydroxyphenyl)methyl]-2-oxoethyl]-4-(1,4-dihydro-2-oxo-3(2H)-quinazolinyl) (BIBN4096BS), a calcitonin gene-related peptide (CGRP) receptor antagonist, can alleviate the symptoms of migraine and is highly selective for CGRP over adrenomedullin (AM) receptors. These receptors are heterodimers of the calcitonin receptor-like receptor (CL) and receptor activity modifying proteins (RAMPs), with the pharmacological properties determined by the RAMP subunit. BIBN4096BS-sensitive CGRP(1) receptors are CL/RAMP1, whereas BIBN4096BS-insensitive AM receptors are CL/RAMP2 or CL/RAMP3 (AM(1) and AM(2), respectively), implicating RAMP1 in conferring BIB-N4096BS sensitivity. Because calcitonin receptors [CT((a))] also interact with RAMP1 [AMY(1(a)) receptors], BIBN4096BS could also have affinity for these receptors. To test this, receptors were transfected into COS-7 cells and agonist-stimulated cAMP levels measured in the presence and absence of antagonists. We found that AMY(1(a)) receptors were approximately 150-fold less sensitive to BIBN4096BS antagonism than CGRP(1) receptors. In contrast, AMY(3(a)) [CT((a))/RAMP3] or AM(2) receptors were not sensitive to BIBN4096BS antagonism. We investigated Trp74 in RAMP1, a residue implicated in the species selectivity of BIBN4096BS. BIBN4096BS affinity was reduced at AMY(1(a)) and CGRP(1) receptors when this residue was mutated to lysine or alanine. The equivalent residue in RAMP3, Glu74, when mutated to tryptophan (E74W), induced BIBN4096BS sensitivity at AM(2) and AMY(3(a)) receptors. It is interesting that a selective reduction in AM potency was observed at E74W AM(2) receptors, implicating this residue in AM interactions with this receptor. These data support the importance of Trp74 in RAMP1 in the interaction of BIBN4096BS with CGRP(1) and AMY(1(a)) receptors and identified Glu74 in RAMP3 as the first amino acid in RAMP important for agonist interactions with calcitonin-family receptors.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, University of Auckland, Symonds Street, Auckland, New Zealand
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487
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Steinhoff M, Bienenstock J, Schmelz M, Maurer M, Wei E, Bíró T. Neurophysiological, neuroimmunological, and neuroendocrine basis of pruritus. J Invest Dermatol 2006; 126:1705-18. [PMID: 16845410 DOI: 10.1038/sj.jid.5700231] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pruritus (itch) can be defined as an unpleasant cutaneous sensation associated with the immediate desire to scratch. Recent findings have identified potential classes of endogenous "itch mediators" and establish a modern concept for the pathophysiology of pruritus. First, there in no universal peripheral itch mediator, but disease-specific sets of involved mediators. Second, numerous mediators of skin cells can activate and sensitize pruritic nerve endings, and even modulate their growth. Our knowledge of itch processing in the spinal cord and the involved centers in the central nervous system is rapidly growing. This review summarizes the current information about the significance of neuron-skin interactions, ion channels, neuropeptides, proteases, cannabinoids, opioids, kinins, cytokines, biogenic amines, neurotransmitters, and their receptors in the pathobiology of pruritus. A deeper understanding of these circuits is required for the development of novel antipruritic strategies.
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Affiliation(s)
- Martin Steinhoff
- Department of Dermatology, IZKF Münster, Ludwig Boltzmann-Institute for Immunobiology of the Skin, University Hospital Muenster, Muenster, Germany.
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488
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Dong F, Taylor MM, Samson WK, Ren J. Intermedin (adrenomedullin-2) enhances cardiac contractile function via a protein kinase C- and protein kinase A-dependent pathway in murine ventricular myocytes. J Appl Physiol (1985) 2006; 101:778-84. [PMID: 16763098 DOI: 10.1152/japplphysiol.01631.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Intermedin (IMD), also called adrenomedullin-2, is a 47-amino acid peptide from the calcitonin gene-related peptide (CGRP)/adrenomedullin family of peptides. Recent studies suggest that IMD may participate in the regulation of cardiovascular function and fluid and electrolyte homeostasis. To evaluate the role of IMD on cardiomyocyte contractile function, electrically paced murine ventricular myocytes were acutely exposed to IMD, and the following indexes were determined: peak shortening (PS), time to PS, time-to-90% relengthening, and maximal velocity of shortening and relengthening. Intracellular Ca2+ was assessed using fura 2-AM fluorescent microscopy. Our results revealed that IMD (10 pM to 10 nM) significantly increased PS and maximal velocity of shortening and relengthening in ventricular myocytes, the maximal effect of which (∼46%) was somewhat comparable to those elicited by CGRP (1 nM) and adrenomedullin (100 nM). Exposure of IMD significantly shortened time-to-90% relengthening without affecting time to PS, similar to CGRP and adrenomedullin. IMD also enhanced intracellular Ca2+ release, with a maximal increase of ∼50%, and facilitated the intracellular Ca2+ decay rate. The IMD-induced effects were abolished by the protein kinase C inhibitor chelerythrine (1 μM), downregulation of protein kinase C using phorbol 12-myristate 13-acetate (1 μM), and the protein kinase A inhibitor H89 (1 μM). Our data suggest that IMD acutely augments cardiomyocyte contractile function through, at least in part, a protein kinase C- and protein kinase A-dependent mechanism.
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Affiliation(s)
- Feng Dong
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071-3375, USA
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489
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Premkumar LS, Raisinghani M. Nociceptors in cardiovascular functions: complex interplay as a result of cyclooxygenase inhibition. Mol Pain 2006; 2:26. [PMID: 16916451 PMCID: PMC1563450 DOI: 10.1186/1744-8069-2-26] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 08/17/2006] [Indexed: 03/28/2023] Open
Abstract
Prostaglandins (PGs) are requisite components of inflammatory pain as indicated by the efficacy of cyclooxygenase 1/2 (COX1/2) inhibitors. PGs do not activate nociceptive ion channels directly, but sensitize them by downstream mechanisms linked to G-protein coupled receptors. Antiinflammatory effects are purported to arise from inhibition of synthesis and/or release of proinflammatory agents. Release of these agents from peripheral and central terminals of sensory neurons modulates nociceptive input from the periphery and synaptic transmission at the first sensory synapse, respectively. Heart and blood vessels are densely innervated by sensory nerve endings that express chemo-, mechano-, and thermo-sensitive receptors. Activation of these receptors mediates synthesis and/or release of vasoactive agents by virtue of their Ca2+permeability. In this article, we discuss that inhibition of COX2 reduces PG synthesis and renders beneficial effects by preventing sensitization of nociceptors, but at the same time, it might contribute to deleterious cardiovascular effects by compromising the synthesis and/or release of vasoactive agents.
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Affiliation(s)
- Louis S Premkumar
- Department of Pharmacology, Southern Illinois University School of Medicine Springfield, IL 62702, USA
| | - Manish Raisinghani
- Department of Pharmacology, Southern Illinois University School of Medicine Springfield, IL 62702, USA
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490
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Nikitenko LL, Blucher N, Fox SB, Bicknell R, Smith DM, Rees MCP. Adrenomedullin and CGRP interact with endogenous calcitonin-receptor-like receptor in endothelial cells and induce its desensitisation by different mechanisms. J Cell Sci 2006; 119:910-22. [PMID: 16495482 DOI: 10.1242/jcs.02783] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) are related peptides with distinct pharmacological profiles. Calcitonin-receptor-like receptor (CRLR, now known as CL) can function as either an AM receptor or a CGRP receptor, when cotransfected with receptor-activity-modifying proteins (RAMPs) that define ligand-binding specificity. The aim of the present study was to determine the role of endogenously expressed CL (EndoCL) in generating endogenous AM and CGRP receptors. We raised anti-human CL antibody and identified microvascular endothelial cells (MVECs) as a major CL-expressing cell type in tissues by immunohistochemistry. Cultured MVECs continue to express EndoCL as well as fully active endogenous AM- and CGRP-sensitive receptors in vitro, as demonstrated by the ability of both peptides to induce migration and Akt phosphorylation. We therefore tested the hypothesis that endothelial EndoCL can interact with both AM and CGRP by examining receptor internalisation and desensitisation (loss of the ability to induce Akt phosphorylation). We found that agonist-mediated internalisation of EndoCL occurs in response to AM but not CGRP in MVECs. However, AM-induced EndoCL internalisation was blocked by antagonists of both AM and CGRP receptors: AM(22-52) and CGRP(8-37), respectively. Furthermore, AM-induced EndoCL internalisation resulted in desensitisation not only of AM but also of CGRP receptors. Finally, CGRP also induced desensitisation of both endogenous AM and CGRP receptors, but did not mediate EndoCL internalisation despite interaction with this receptor. Thus, EndoCL interacts with both AM and CGRP, and simultaneously acts as a receptor for both peptides (i.e acting as an endogenous AM/CGRP receptor) in endothelial cells. Interaction with either ligand is sufficient to induce EndoCL desensitisation to both AM and CGRP, but differential mechanisms are involved since only AM induces EndoCL internalisation. These novel findings regarding regulation of EndoCL function in endothelial cells are likely to be of importance in conditions where AM or CGRP levels are elevated, such as cardiovascular disease, diabetes and inflammation.
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Affiliation(s)
- Leonid L Nikitenko
- Nuffield Department of Obstetrics and Gynaecology, The University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
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491
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Isaka M, Imamura M, Sakuma I, Makino Y, Shiiya N, Yasuda K. Cardiopulmonary bypass influences the plasma levels of calcitonin gene-related peptides in dogs: effects of hemofiltration and hemodilution. Res Vet Sci 2006; 82:110-4. [PMID: 16839577 DOI: 10.1016/j.rvsc.2006.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 02/25/2006] [Accepted: 05/06/2006] [Indexed: 11/19/2022]
Abstract
Calcitonin gene-related peptides (CGRP), which are potent vasodilators, are elevated during cardiopulmonary bypass (CPB) in humans. We evaluated the plasma levels of CGRP in dogs during CPB with hemofiltration with and without hemodilution. Female beagles were divided into control (n=5) and hemodilution (n=5) groups. The CPB with hemofiltration was performed with or without hemodilution. For the measurement of CGRP, blood samples were collected pre-CPB, during CPB, and post-CPB. The concentrations of CGRP in the hemofiltration solution were measured. Although the CPB elevated the plasma CGRP levels in both groups, its elevation was significant in the hemodilution group when compared to the pre-CPB levels. CGRP levels returned to normal post-CPB. Significant differences were found between the two groups in the CGRP amount in hemofiltration. The results show that hemofiltration should be used during CPB to decrease the plasma levels of CGRP.
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Affiliation(s)
- Mitsuhiro Isaka
- Department of Cardiovascular Surgery, Hokkaido University School of Medicine, Kita-14, Nishi-5, Kita-ku, Sapporo 060-8648, Japan.
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492
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Suzuki K, Kobayashi Y, Morita T. Serum calcitonin gene-related peptide levels in untreated prostate cancer patients. Int J Urol 2006; 13:781-4. [PMID: 16834660 DOI: 10.1111/j.1442-2042.2006.01402.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The role of calcitonin gene-related peptide (CGRP) in prostate cancer has not been fully understood. Moreover, the serum CGRP level in prostate cancer patients has never been reported. We measured the serum CGRP levels in untreated prostate cancer patients to elucidate its clinical significance. MATERIALS AND METHODS We used 36 serum samples from prostate cancer patients. All patients had never received any treatment. Serum CGRP was measured by immunoradiometric assay, and we analysed the association between serum CGRP level and clinicopathological factors. RESULTS Serum CGRP levels in the patients with higher clinical stages and histological grade were significantly higher than in those with lower stages and grade, respectively. But the levels did not correlate with the patient's age, liver or renal functions, serum prostate-specific antigen levels. CONCLUSION Serum CGRP levels were significantly elevated in the patients with high grade or high stage untreated prostate cancer patients. Measurement of the serum CGRP may be a useful predictor of staging or grading of prostate cancer in the untreated prostate cancer patients.
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Affiliation(s)
- Kazumi Suzuki
- Department of Urology, Jichi Medical School, Tochigi, Japan.
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493
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Abstract
CGRP is an important neuropeptide found throughout the cardiovascular system. However, until recently it has been difficult to define its pharmacology or physiological role because of the lack of suitable antagonists. BIBN4096BS is a high-affinity, nonpeptide antagonist that shows much greater selectivity for human CGRP1 receptors compared to any other drug. Its pharmacology has been defined with studies on transfected cells or cell lines endogenously expressing receptors of known composition. These have allowed confirmation that in many human blood vessels, CGRP is working via CGRP1 receptors. However, it also interacts with other CGRP-activated receptors, of unknown composition. In vivo, clinical studies have shown that BIBN4096BS is likely to be useful in the treatment of migraine. It has also been used to define the role of CGRP in phenomena such as plasma extravasation and cardioprotection following ischemia.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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494
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Bailey RJ, Hay DL. Pharmacology of the human CGRP1 receptor in Cos 7 cells. Peptides 2006; 27:1367-75. [PMID: 16375989 DOI: 10.1016/j.peptides.2005.11.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 11/15/2005] [Accepted: 11/16/2005] [Indexed: 10/25/2022]
Abstract
Only limited pharmacological characterization of the CGRP1 receptor, a heterodimer of the calcitonin (CT) receptor-like receptor (CL) and receptor activity-modifying protein 1 has been performed in cells that do not endogenously express RAMP2. We characterized the receptor in RAMP-deficient Cos 7 cells by measuring cAMP responses following agonist treatment in the absence or presence of antagonists. Potent cAMP responses to human alpha-and beta-CGRP (Cys(Et)2,7)halphaCGRP and human adrenomedullin (AM) were observed. Adrenomedullin15-52 was also an effective agonist of the CGRP1 receptor but human and salmon calcitonin and rat amylin were only weak agonists. As expected, BIBN4096BS and CGRP(8-37) were effective antagonists of the CGRP1 receptor. (Cys(Acm)2,7)halphaCGRP also antagonized CGRP responses. Antagonists of related receptors were only weakly able to inhibit CGRP responses.
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Affiliation(s)
- Richard J Bailey
- Proteomics & Biomedicine Research Group, School of Biological Sciences, University of Auckland, 3 Symonds Street, Private Bag 92 019, New Zealand
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495
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Martinez V, Wang L, Taché Y. Peripheral adrenomedullin inhibits gastric emptying through CGRP8-37 -sensitive receptors and prostaglandins pathways in rats. Peptides 2006; 27:1376-82. [PMID: 16337713 DOI: 10.1016/j.peptides.2005.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 11/04/2005] [Accepted: 11/04/2005] [Indexed: 11/24/2022]
Abstract
The effects of intravenous (iv) adrenomedullin (AM) on gastric emptying were investigated in conscious rats. AM induced a maximal 50% inhibition of gastric emptying at a dose of 1.2 nmol/kg. AM was about two-fold less potent than alpha-calcitonin gene-related peptide (alpha-CGRP), which induced a similar 50% maximal inhibition of gastric emptying at 0.6 nmol/kg. Delayed gastric emptying induced by i.v. AM and alpha-CGRP was prevented by peripheral injection of the selective CGRP1 antagonist, CGRP8-37, and by pretreatment with indomethacin, while not altered by blockade of the sympathetic nervous system with propranolol. These data indicate that peripheral AM inhibits gastric emptying through the interaction with CGRP8-37 -sensitive receptors, likely CGRP1 receptors, and the recruitment of prostaglandin-dependent mechanisms.
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Affiliation(s)
- V Martinez
- CURE: Digestive Diseases Research Center, Department of Medicine, David Geffen School of Medicine at UCLA, University of California Los Angeles and VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA.
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496
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Sternberg EM. Neural regulation of innate immunity: a coordinated nonspecific host response to pathogens. Nat Rev Immunol 2006; 6:318-28. [PMID: 16557263 PMCID: PMC1783839 DOI: 10.1038/nri1810] [Citation(s) in RCA: 697] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The central nervous system (CNS) regulates innate immune responses through hormonal and neuronal routes. The neuroendocrine stress response and the sympathetic and parasympathetic nervous systems generally inhibit innate immune responses at systemic and regional levels, whereas the peripheral nervous system tends to amplify local innate immune responses. These systems work together to first activate and amplify local inflammatory responses that contain or eliminate invading pathogens, and subsequently to terminate inflammation and restore host homeostasis. Here, I review these regulatory mechanisms and discuss the evidence indicating that the CNS can be considered as integral to acute-phase inflammatory responses to pathogens as the innate immune system.
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Affiliation(s)
- Esther M Sternberg
- Section on Neuroendocrine Immunology and Behaviour, National Institute of Mental Health, National Institutes of Health, 5625 Fishers Lane, Room 4N-13, MSC-9401, Rockville, Maryland 20852, USA.
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497
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Bronský J, Průsa R, Nevoral J. The role of amylin and related peptides in osteoporosis. Clin Chim Acta 2006; 373:9-16. [PMID: 16797521 DOI: 10.1016/j.cca.2006.05.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2006] [Revised: 05/02/2006] [Accepted: 05/05/2006] [Indexed: 12/18/2022]
Abstract
Osteoporosis is a systemic skeletal disorder that remains a major public health problem due to significant fracture-associated morbidity and mortality. Because it has been shown that individuals having type I diabetes mellitus also suffer from osteopenia or osteoporosis, there is probably a pathophysiological mechanism that links pancreatic beta cell insufficiency with inappropriate bone formation. Many factors have been suggested, including amylin, a product of pancreatic beta cells with structural and functional similarity to calcitonin. Amylin has been shown to stimulate bone development via action on osteoblasts and osteoclasts. Recently, amylin receptors have been identified as complexed calcitonin receptor with receptor activity modifying proteins. Moreover, a synthetic amylin analogue (pramlintide) has been developed for clinical use. These findings including results from in vitro animal and human studies suggest a role for amylin as a potential diagnostic and therapeutical tool in patients with various bone diseases including osteoporosis. However, other structurally and functionally related hormones that affect bone metabolism should also be taken in account including calcitonin, calcitonin gene-related peptide and adrenomedullin.
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Affiliation(s)
- Jirí Bronský
- Department of Clinical Biochemistry and Pathobiochemistry, 2nd Medical Faculty, Charles University and Faculty Hospital Motol, V Uvalu 84, 150 06 Prague 5, Czech Republic.
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498
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Cox CM, D'Agostino SL, Miller MK, Heimark RL, Krieg PA. Apelin, the ligand for the endothelial G-protein-coupled receptor, APJ, is a potent angiogenic factor required for normal vascular development of the frog embryo. Dev Biol 2006; 296:177-89. [PMID: 16750822 DOI: 10.1016/j.ydbio.2006.04.452] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 04/06/2006] [Accepted: 04/19/2006] [Indexed: 10/24/2022]
Abstract
The peptide growth factor apelin is the high affinity ligand for the G-protein-coupled receptor APJ. During embryonic development of mouse and frog, APJ receptor is expressed at high levels in endothelial precursor cells and in nascent vascular structures. Characterization of Xenopus apelin shows that the sequence of the bioactive region of the peptide is perfectly conserved between frogs and mammals. Embryonic expression studies indicate that apelin is expressed in, or immediately adjacent to, a subset of the developing vascular structures, particularly the intersegmental vessels. Experimental inhibition of either apelin or APJ expression, using antisense morpholino oligos, results in elimination or disruption of intersegmental vessels in a majority of embryos. In gain of function experiments, apelin peptide is a potent angiogenic factor when tested using two in vivo angiogenesis assays, the frog embryo and the chicken chorioallantoic membrane. Furthermore, studies using the mouse brain microvascular cell line bEnd.3 show that apelin acts as a mitogenic, chemotactic and anti-apoptotic agent for endothelial cells in culture. Finally, we show that, similar to a number of other angiogenic factors, expression of the apelin gene is increased under conditions of hypoxia. Taken together, these studies indicate that apelin is required for normal vascular development in the frog embryo and has properties consistent with a role during normal and pathological angiogenesis.
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Affiliation(s)
- Christopher M Cox
- Department of Cell Biology and Anatomy, University of Arizona Health Sciences Center, 1501 N. Campbell Avenue, Tucson, AZ 85724-5044, USA
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499
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Keeble JE, Brain SD. Capsaicin-induced vasoconstriction in the mouse knee joint: a study using TRPV1 knockout mice. Neurosci Lett 2006; 401:55-8. [PMID: 16584841 DOI: 10.1016/j.neulet.2006.02.083] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 02/07/2006] [Accepted: 02/22/2006] [Indexed: 11/30/2022]
Abstract
Capsaicin is the pungent component of chilli peppers that concomitantly activates and desensitizes C-fibre and Adelta sensory nerve fibres. Stimulation causes an acute neurogenic response including vasodilation, plasma extravasation and hypersensitivity. However, in the present study we have shown that capsaicin produces a dose-dependent vasoconstrictor effect in the mouse knee joint via Transient Receptor Potential Vanilloid 1 (TRPV1) receptor activation. A (125)I-albumin accumulation technique showed that the intravascular volume of capsaicin-treated joints in wild type (WT) mice was significantly reduced compared to TRPV1 knockout mice (p<0.01). Similarly, a laser Doppler technique showed significantly reduced blood flow in the capsaicin-treated joints of WT compared to TRPV1 knockout mice (p<0.001). Pretreatment with guanethinidine (50 mg kg(-1), i.p.) had no effect on the vasoconstriction. These data are important considering the involvement of TRPV1 receptors in joint disease. The mechanisms underlying the vasoconstriction therefore require further investigation.
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Affiliation(s)
- Julie Elizabeth Keeble
- Cardiovascular Division, New Hunt's House, King's College London, Guy's Campus, SE1 1UL, UK.
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500
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Zhang Z, Dickerson IM, Russo AF. Calcitonin gene-related peptide receptor activation by receptor activity-modifying protein-1 gene transfer to vascular smooth muscle cells. Endocrinology 2006; 147:1932-40. [PMID: 16373421 DOI: 10.1210/en.2005-0918] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The neuropeptide calcitonin gene-related peptide (CGRP) is a potent vasodilator that plays a protective role in the cardiovascular system. The receptor for CGRP is an unusual complex of the G protein-coupled calcitonin-like receptor and an obligate receptor activity modifying protein-1 (RAMP1). In this report we provide the first evidence that RAMP1 is rate limiting in vascular smooth muscle cells. Although cultured rat aorta smooth muscle cells express calcitonin like-receptor and RAMP1, we found that CGRP is not a potent activator of the receptor. After overexpression of RAMP1 by adenoviral gene transfer, there was a striking increase in CGRP-induced production of cAMP, with a 75-fold decrease in the EC(50) and a 1.5-fold increase in the maximal response. The biological consequence of this increased receptor activity was observed in three different paradigms. First, RAMP1 gene transfer caused a CGRP-dependent decrease in cell proliferation. Second, RAMP1 and CGRP treatment led to a 3-fold greater free radical-induced reduction in cell number. Finally, RAMP1 gene transfer resulted in a 5-fold CGRP-dependent increase in terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling-positive apoptotic cells upon serum withdrawal. The mechanisms underlying these effects involved cAMP-dependent pathways. We propose that RAMP1 gene transfer may be an effective strategy for increasing the effectiveness of CGRP-induced decrease in restenosis after aortic angioplasty.
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MESH Headings
- Adenoviridae/genetics
- Animals
- Apoptosis
- Calcitonin Receptor-Like Protein
- Cell Proliferation
- Cells, Cultured
- Cyclic AMP/biosynthesis
- Gene Transfer, Horizontal
- Genetic Therapy
- Humans
- Intracellular Signaling Peptides and Proteins/genetics
- Male
- Membrane Proteins/genetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor Activity-Modifying Protein 1
- Receptor Activity-Modifying Proteins
- Receptors, Calcitonin/physiology
- Receptors, Calcitonin Gene-Related Peptide/physiology
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Affiliation(s)
- Zhongming Zhang
- Department of Physiology and Biophysics, University of Iowa, Iowa City, 52242, USA
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