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AlMarabeh S, Abdulla MH, O'Halloran KD. Is Aberrant Reno-Renal Reflex Control of Blood Pressure a Contributor to Chronic Intermittent Hypoxia-Induced Hypertension? Front Physiol 2019; 10:465. [PMID: 31105584 PMCID: PMC6491928 DOI: 10.3389/fphys.2019.00465] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 04/04/2019] [Indexed: 12/16/2022] Open
Abstract
Renal sensory nerves are important in the regulation of body fluid and electrolyte homeostasis, and blood pressure. Activation of renal mechanoreceptor afferents triggers a negative feedback reno-renal reflex that leads to the inhibition of sympathetic nervous outflow. Conversely, activation of renal chemoreceptor afferents elicits reflex sympathoexcitation. Dysregulation of reno-renal reflexes by suppression of the inhibitory reflex and/or activation of the excitatory reflex impairs blood pressure control, predisposing to hypertension. Obstructive sleep apnoea syndrome (OSAS) is causally related to hypertension. Renal denervation in patients with OSAS or in experimental models of chronic intermittent hypoxia (CIH), a cardinal feature of OSAS due to recurrent apnoeas (pauses in breathing), results in a decrease in circulating norepinephrine levels and attenuation of hypertension. The mechanism of the beneficial effect of renal denervation on blood pressure control in models of CIH and OSAS is not fully understood, since renal denervation interrupts renal afferent signaling to the brain and sympathetic efferent signals to the kidneys. Herein, we consider the currently proposed mechanisms involved in the development of hypertension in CIH disease models with a focus on oxidative and inflammatory mediators in the kidneys and their potential influence on renal afferent control of blood pressure, with wider consideration of the evidence available from a variety of hypertension models. We draw focus to the potential contribution of aberrant renal afferent signaling in the development, maintenance and progression of high blood pressure, which may have relevance to CIH-induced hypertension.
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Affiliation(s)
- Sara AlMarabeh
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Mohammed H Abdulla
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
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Excitation-Contraction Coupling in Ureteric Smooth Muscle: Mechanisms Driving Ureteric Peristalsis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:103-119. [DOI: 10.1007/978-981-13-5895-1_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Steinbach A, Schaper K, Koenen A, Schlüter T, Zimmermann U, Rettig R, Grisk O. Role of endothelin-1 for the regulation of renal pelvic function. Pflugers Arch 2016; 468:1467-78. [DOI: 10.1007/s00424-016-1848-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/17/2016] [Accepted: 06/06/2016] [Indexed: 10/21/2022]
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Jankovic SM, Stojadinovic D, Stojadinovic M, Jankovic SV, Djuric JM, Stojic I, Kostic M. Angiotensin Receptor Blocker Losartan Inhibits Spontaneous Motility of Isolated Human Ureter. Eur J Drug Metab Pharmacokinet 2015; 41:835-838. [PMID: 26328808 DOI: 10.1007/s13318-015-0298-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Ureteral motility is essential for elimination of intraluminal stones, and it may be adversely affected by cardiovascular drugs that a patient is taking chronically. The aim of our study was to test whether ACE inhibitors and an angiotensin receptor blocker may influence spontaneous contractions of isolated human ureter. METHODS Both phasic and tonic contractions of the isolated ureteral segments taken from 10 patients were measured as changes of the longitudinal tension or pressure recordings. Captopril, enalapril and losartan were separately added to the organ baths cumulatively. RESULTS While enalapril (2.7 × 10-7-3.9 × 10-4 M) and captopril (6.1 × 10-7-2.7 × 10-3 M) did not affect either spontaneous activity or tone of isolated ureteral segments, losartan (2.9 × 10-7-4.2 × 10-4 M) caused concentration-dependent inhibition of spontaneous contractions of the segments (50 % effective concentration (EC50) = 13.46 ± 1.80 × 10-6 M; F = 10.72, r = 0.79, p < 0.001). CONCLUSIONS Due to differences in molecular mechanism of action, angiotensin receptor blocker losartan does and ACE inhibitors captopril and enalapril do not inhibit spontaneous contractions of isolated human ureter.
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Affiliation(s)
- Slobodan M Jankovic
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia.
| | - Dobrivoje Stojadinovic
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia
| | - Miroslav Stojadinovic
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia
| | - Snezana V Jankovic
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia
| | - Janko M Djuric
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia
| | - Isidora Stojic
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia
| | - Marina Kostic
- Faculty of Medical Sciences, University of Kragujevac, and Clinical Center, ul. Svetozara Markovica 69, 34000, Kragujevac, Serbia
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Materazzi S, Minocci D, De Siena G, Benemei S, Nassini R. Ureteral relaxation through calcitonin gene-related peptide release from sensory nerve terminals by hypotonic solution. Int J Urol 2015; 22:878-83. [DOI: 10.1111/iju.12837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/12/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Serena Materazzi
- Section of Clinical Pharmacology and Oncology; Department of Health Sciences; University of Florence; Florence Italy
| | - Daiana Minocci
- Section of Clinical Pharmacology and Oncology; Department of Health Sciences; University of Florence; Florence Italy
| | - Gaetano De Siena
- Section of Clinical Pharmacology and Oncology; Department of Health Sciences; University of Florence; Florence Italy
| | - Silvia Benemei
- Section of Clinical Pharmacology and Oncology; Department of Health Sciences; University of Florence; Florence Italy
| | - Romina Nassini
- Section of Clinical Pharmacology and Oncology; Department of Health Sciences; University of Florence; Florence Italy
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Colucci M, Mastriota M, Maione F, Di Giannuario A, Mascolo N, Palmery M, Severini C, Perretti M, Pieretti S. Guinea pig ileum motility stimulation elicited by N-formyl-Met-Leu-Phe (fMLF) involves neurotransmitters and prostanoids. Peptides 2011; 32:266-71. [PMID: 21126546 DOI: 10.1016/j.peptides.2010.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 11/15/2010] [Accepted: 11/15/2010] [Indexed: 11/16/2022]
Abstract
In guinea-pig ileum (GPI), the chemotactic peptide N-formyl-Met-Leu-Phe-OH (fMLF) possesses spasmogenic properties through the activation of formyl peptide receptors (FPRs). Despite this, the mediators involved remain to be elucidated. fMLF (1nM-1μM) induced a dose-dependent contraction of GPI (EC(50)=24nM), that is blocked by pre-treatment with the FPRs antagonist Boc(2). The pre-treatment with tetrodotoxin (TTX) atropine or with SR140333 reduced the fMLF-induced contraction, whereas with hexamethonium, MEN10627, SB222200, mepyramine, cimetidine, thioperamide or methysergide did not produce any effect. With DuP697 pre-treatment, but not with piroxicam, reduced the fMLF-induced contraction. After stimulation with 24nM fMLF, a strong increase in the PGE(2) levels was observed. Finally, the concomitant blocking of the NK(1) receptor, the muscarinic receptors and COX-2 abolished the GPI contractions induced by fMLF. fMLF induced a concentration-dependent contraction of guinea-pig jejunum (EC(50)=11nM), proximal colon (EC(50)=3.5nM) and distal colon (EC(50)=2.2nM), with a time-course similar to that observed in GPI. In these preparations as well, the co-administration of atropine, SR140333 and DuP697 abolished the contractions induced by fMLF. Intraperitoneal injection of fMLF (0.1 or 1μmol/kg) enhanced the gastrointestinal motility in mice, abolished by the co-administration of atropine, SR140333 and DuP697. In conclusion, we showed that fMLF exerts spasmogenic actions on guinea-pig intestine both in vitro and in vivo through the release of acetylcholine and substance P from myenteric motorneurons and through prostanoids, probably from the inflammatory cells of the enteric immune system.
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Affiliation(s)
- Mariantonella Colucci
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
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Kawata H, Hirano K, Nishimura J, Kubo C, Kanaide H. The mechanism underlying the contractile effect of a chemotactic peptide, formyl-Met-Leu-Phe on the guinea-pig Taenia coli. Br J Pharmacol 2006; 145:353-63. [PMID: 15735654 PMCID: PMC1576144 DOI: 10.1038/sj.bjp.0706181] [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] [Indexed: 11/08/2022] Open
Abstract
1 The contractile mechanism of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) was investigated in the guinea-pig Taenia coli, by simultaneously monitoring the changes in the cytosolic Ca(2+) concentration ([Ca(2+)](i)) and force. 2 fMLP induced a significant elevation of [Ca(2+)](i) and force at concentrations higher than 10 nM. The maximal response was obtained at a concentration of higher than 1 microM. 3 fMLP (10 microM) augmented the force development induced by a stepwise increment of the extracellular Ca(2+) concentration during 60 mM K(+) depolarization, while it had no effect on the [Ca(2+)](i) elevation, and thus produced a greater force for a given elevation of [Ca(2+)](i) than 60 mM K(+) depolarization. 4 The removal of extracellular Ca(2+) completely abolished the fMLP-induced contraction. The fMLP-induced [Ca(2+)](i) elevation was inhibited substantially but not completely by 10 microM diltiazem, partly by 10 microM SK&F 96365, and completely by their combination. 5 Y27632, a specific inhibitor of rho-kinase, had no significant effect on the fMLP-induced [Ca(2+)](i) elevation and force development. 6 Chenodeoxycholic acid, a formyl peptide receptor antagonist, specifically abolished the fMLP-induced contraction but not high K(+)- or carbachol-induced contractions. 7 A dual lipoxygenase/cyclooxygenase inhibitor, a 5-lipoxygenase inhibitor, a nonselective leukotriene receptor antagonist, and a selective type 1 cysteinyl-containing leukotriene receptor antagonist specifically reduced the fMLP-induced contraction. 8 We suggest that the low-affinity-type fMLP receptor and lipoxygenase metabolites of arachidonic acid are involved in the fMLP-induced contraction in the guinea-pig T. coli. This contraction mainly depends on the [Ca(2+)](i) elevation due to Ca(2+) influx and the enhancement of Ca(2+) sensitivity in the contractile apparatus.
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Affiliation(s)
- Hiroshi Kawata
- Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
| | - Katsuya Hirano
- Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
| | - Junji Nishimura
- Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
| | - Chiharu Kubo
- Department of Psychosomatic Medicine, Graduate School of Medical Sciences, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
| | - Hideo Kanaide
- Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
- Kyushu University COE Program on Lifestyle-Related Diseases, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
- Author for correspondence:
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Bacterial Toxin N-Formyl-Methionyl-Leucyl-Phenylalanine Acutely Contracts Human and Rabbit Detrusor Through the Release of Eicosanoids. J Urol 2002. [DOI: 10.1097/00005392-200206000-00066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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SCHWARZ NICOLAST, JUNG SUKYOUNG, KALFF JÖRGC, CHANCELLOR MICHAEL, BAUER ANTHONYJ. Bacterial Toxin N-Formyl-Methionyl-Leucyl-Phenylalanine Acutely Contracts Human and Rabbit Detrusor Through the Release of Eicosanoids. J Urol 2002. [DOI: 10.1016/s0022-5347(05)65045-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- NICOLAS T. SCHWARZ
- From the Departments of Surgery, Urology and Medicine/Gastroenterology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania
| | - SUK YOUNG JUNG
- From the Departments of Surgery, Urology and Medicine/Gastroenterology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania
| | - JÖRG C. KALFF
- From the Departments of Surgery, Urology and Medicine/Gastroenterology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania
| | - MICHAEL CHANCELLOR
- From the Departments of Surgery, Urology and Medicine/Gastroenterology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania
| | - ANTHONY J. BAUER
- From the Departments of Surgery, Urology and Medicine/Gastroenterology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania
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Sann H. Chemosensitivity of nociceptive, mechanosensitive afferent nerve fibres in the guinea-pig ureter. Eur J Neurosci 1998; 10:1300-11. [PMID: 9749784 DOI: 10.1046/j.1460-9568.1998.00141.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mechanosensitivity and chemosensitivity of afferent fibres were investigated in an in vitro preparation of the guinea-pig ureter. Electrophysiological recordings were obtained from 5 U-1 (low mechanical threshold, contraction-sensitive) and 74 U-2 units (high threshold). U-2 units had significant higher levels of spontaneous activity, lower conduction velocities, higher mechanical thresholds (U-1: 7 mmHg; U-2: 39 mmHg), less pronounced phasic responses and longer latencies in the response to distensions than the U-1 units. For chemical stimulation, guinea-pig urine (> 800 mosmol/L), bradykinin and capsaicin were applied intraluminally. The responses of U-1 units mainly corresponded to the contractions induced by the chemical stimulation. The vast majority of the U-2 units were excited by urine, bradykinin (threshold: 0.1-1 microM) and capsaicin (threshold: 0.03-0.3 microM). The responses to urine could be mimicked by high concentrations of potassium ions (> 200 mM), but not by an equiosmolar solution of NaCl, urea and mannitol. Chemical stimulation could also result in a transient sensitization of the U-2 units to mechanical stimuli. In the anaesthetized guinea-pig, pseudo-affective responses could be evoked by ureteric distension (threshold: 30-60 mmHg) and serosal application of capsaicin. Intraluminal application of urine in vivo did not evoke any reactions, suggesting that the responses of the U-2 units to urine might be due to an impaired barrier function of the urothelium in vitro. The data are in agreement with the hypothesis that U-2 units are visceral polymodal nociceptors. Since the U-1 units were also able to encode at least noxious mechanical stimuli, their involvement in visceral nociception cannot be excluded.
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Affiliation(s)
- H Sann
- Physiologisches Institut, Tierärztliche Hochschule, Hannover, Germany.
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Zheng F, Lawson SN. Neurokinin A in rat renal afferent neurons and in nerve fibres within smooth muscle and epithelium of rat and guinea-pig renal pelvis. Neuroscience 1997; 76:1245-55. [PMID: 9027883 DOI: 10.1016/s0306-4522(96)00441-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Neurokinin A-like immunoreactivity of dorsal root ganglion neurons innervating the kidney were studied with retrograde tracing of FluoroGold dye applied to the cut renal nerves. The proportions and sizes of renal afferent neurons with neurokinin A-like immunoreactivity were quantified in T9-L2 dorsal root ganglia from five rats. Of 240 renal afferent neuronal somata examined, 26 +/- 3% (S.E.M.) showed neurokinin A-like immunoreactivity. Compared with the overall size distribution of renal afferent neurons, those staining for neurokinin A were mostly small-sized neurons with a few medium-sized neurons. All somata with neurokinin A-like immunoreactivity were neurofilament-poor as judged by labelling with an anti-neurofilament antibody, RT97, and it is therefore likely that they had unmyelinated fibres. To examine the sites to which the renal afferent fibres with neurokinin A might project, sections of rat and guinea-pig kidney and upper ureter were examined. Fibres with neurokinin A-like immunoreactivity were found beneath and within the transitional epithelium lining the inner surface of the pelvis, and within the smooth muscle layer beneath the transitional epithelium. Epithelial innervation was found only in regions with underlying smooth muscle and loose connective tissue, and not in sites where the epithelium was closely applied to the renal parenchyma. The network of fibres was most dense towards the pelvo-uretic junction. Fibres with neurokinin A-like immunoreactivity were not seen beneath or within the cuboidal/columnar epithelium covering the papilla within the renal pelvis. Furthermore, only very few fibres with neurokinin A were observed penetrating the transitional epithelium of the upper ureter in both rat and guinea-pig. The distribution of fibres labelled with antibodies to substance P and calcitonin gene-related peptide in the renal pelvis was similar to that for fibres with neurokinin A-like immuno-reactivity, although a few fibres penetrated further into the fornices than fibres with neurokinin-A-like immunoreactivity. Thus, many afferent fibres in the renal pelvis may contain neurokinin A as well as substance P and calcitonin gene-related peptide. These fibres may be the source of the neurokinin A, substance P and calcitonin gene-related peptide which can be released by topical capsaicin treatment. In addition they may be the mechano- and chemo-receptive fibres in the renal pelvis that are known to play important roles in renal haemodynamics. The intra-epithelial position of some of these fibres in the epithelial layer suggests a possible chemosensory or osmosensory role.
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Affiliation(s)
- F Zheng
- Department of Physiology, School of Medical Sciences, University of Bristol, UK
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12
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Maggi CA, Giuliani S, Santicioli P. CGRP inhibition of electromechanical coupling in the guinea-pig isolated renal pelvis. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1995; 352:529-39. [PMID: 8751082 DOI: 10.1007/bf00169387] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We aimed at studying the mechanism(s) of the inhibitory effect exerted by calcitonin gene-related peptide (CGRP) on the spontaneous activity of the guinea-pig isolated renal pelvis. In organ bath experiments, CGRP (1-100 nM) produced a concentration-dependent (EC50 8 nM) partial inhibition (Emax about 35% inhibition of motility index) of spontaneous contractions. The potassium (K) channel opener, cromakalim (3-10 microM) promptly suppressed the spontaneous contractions in a glibenclamide-(10 microM) sensitive manner. Glibenclamide (10 microM) did not affect the inhibitory action of CGRP. The calcium (Ca) channel agonist, Bay K 8644 (1 microM), markedly enhanced the spontaneous activity of the renal pelvis and reduced the inhibitory effect of CGRP. The protein kinase A inhibitors Rp-cAMPS (300 microM), H8 (100 microM) and H89 (10 microM), and the blockers of intracellular Ca handling by sarcoplasmic reticulum, ryanodine (100 microM) and thapsigargin (1 microM) did not affect the response to CGRP. The response to CGRP was likewise unaffected by the nitric oxide synthase inhibitor, L-nitroarginine (30 microM) and by the protein kinase G inhibitor, KT5823 (3 microM). Furthermore, the inhibitory action of CGRP was not modified by lowering the extracellular concentration of K (from 5.9 to 1.2 mM) nor by increasing (from 2.5 to 3.75 mM) or decreasing (from 2.5 to 0.25 mM) the extracellular Ca concentration. Replacement of 80% glucose with 2-deoxyglucose (2-DOG) reduced the amplitude of spontaneous contractions, both in the absence and presence of 10 microM glibenclamide. In the presence of 2-DOG, the inhibitory action of CGRP was enhanced at a similar extent, either in the absence or presence of glibenclamide. In sucrose gap, the effect of CGRP (0.1 microM for 5 min) was separately analyzed in the proximal (close to the kidney) and distal (close to the ureter) regions of the renal pelvis. Both preparations discharged spontaneous (pacemaker) action potentials having different shape, duration and frequently. CGRP had no effect on pacemaker potentials in the proximal renal pelvis while producing about 30% reduction of the frequency of pacemaker potentials and motility index in the distal renal pelvis. Cromakalim (3 microM) abolished pacemaker potentials in both regions of the renal pelvis. In conjunction with the results of previous studies in the guinea-pig ureter, the present findings document the existence of remarkable regional differences in the effector mechanisms initiated by CGRP receptor occupancy in the guinea-pig pyeloureteral tract. CGRP appears to be inherently unable to activate glibenclamide-sensitive K channels in the guinea-pig renal pelvis, a mechanism which is central for its ability to suppress latent pacemakers in the ureter. Within the renal pelvis, the sensitivity to the inhibitory effect of CGRP appears in the more distal region, from which an 'ureter-like' action potential is recorded.
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Affiliation(s)
- C A Maggi
- Pharmacology Department A. Menarini Pharmaceuticals, Florence, Italy
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Rae GA, Calixto JB, D'Orléans-Juste P. Effects and mechanisms of action of endothelins on non-vascular smooth muscle of the respiratory, gastrointestinal and urogenital tracts. REGULATORY PEPTIDES 1995; 55:1-46. [PMID: 7724825 DOI: 10.1016/0167-0115(94)00098-i] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- G A Rae
- Department of Pharmacology, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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14
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Meini S, Santicioli P, Maggi CA. Propagation of impulses in the guinea-pig ureter and its blockade by calcitonin gene-related peptide (CGRP). NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1995; 351:79-86. [PMID: 7536304 DOI: 10.1007/bf00169067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The guinea-pig ureter was placed in a three-compartment organ bath to enable the application of electrical stimuli or drugs to its renal end (R-site), the middle region (M-site) or the bladder end (B-site) while recording mechanical activity at the R- and B-sites. All experiments were performed in ureters pre-exposed to capsaicin (10 microM for 15 min) to prevent the release of sensory neuropeptides from afferent nerves. Electrical field stimulation (EFS, 5-25 ms pulse width, 20 V) produced a phasic contraction at the site of stimulation ('direct' response to EFS) which propagated to the other end of the ureter. Section of the ureter at the M-site abolished the propagated response to EFS; after section, EFS applied at the M-site induced a phasic contraction at both the R- and B-sites. Likewise, the application of KCl at the M-site produced phasic contractions at both the R- and B-sites. Tetrodotoxin (1 microM), nifedipine (1 microM) or Bay K 8644 (1 microM) applied at the M-site had no influence on the direct or propagated responses to EFS; nifedipine (10 microM) applied at the M-site abolished the propagated responses without affecting the direct responses to EFS. Bay K 8644 (1 microM) applied at the R-site produced a marked enhancement of the direct response (EFS applied at R-site) while having no effect on the amplitude of the propagated response to EFS.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Meini
- Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy
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15
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Maggi CA. Tachykinins and calcitonin gene-related peptide (CGRP) as co-transmitters released from peripheral endings of sensory nerves. Prog Neurobiol 1995; 45:1-98. [PMID: 7716258 DOI: 10.1016/0301-0082(94)e0017-b] [Citation(s) in RCA: 345] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- C A Maggi
- Department of Pharmacology, A. Menarini Pharmaceuticals, Florence, Italy
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16
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Santicioli P, Maggi CA. Inhibitory transmitter action of calcitonin gene-related peptide in guinea-pig ureter via activation of glibenclamide-sensitive K channels. Br J Pharmacol 1994; 113:588-92. [PMID: 7834212 PMCID: PMC1510123 DOI: 10.1111/j.1476-5381.1994.tb17030.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. In single sucrose gap, electrical field stimulation (EFS, 1-5 Hz) produced graded hyperpolarization of the membrane of the guinea-pig ureter smooth muscle, which was blocked by tetrodotoxin (0.3 microM) or in vitro capsaicin desensitization (3 microM for 15 min). Capsaicin itself produced a transient hyperpolarization of the membrane on its first application. 2. Superfusion with human alpha calcitonin gene-related peptide (CGRP, 30-300 mM) likewise produced a transient hyperpolarization of the membrane, mimicking the neurogenic inhibitory junction potential (i.j.p.). The hyperpolarization by CGRP was unaffected by tetrodotoxin, indicating a postjunctional site of action. 3. Both the EFS-evoked i.j.p. and the CGRP-induced hyperpolarization were inhibited by the CGRP receptor antagonist, CGRP(8-37) (0.3-3 microM) which did not affect the hyperpolarization produced by the KATP channel opener, cromakalim (0.3 microM). 4. The KATP channel blocker, glibenclamide (1 microM) blocked both the EFS-evoked i.j.p. and the CGRP-induced hyperpolarization. 5. When evoked in a low K medium (1.2 mM, KCl being replaced by an equimolar amount of NaCl), the EFS-evoked i.j.p. and the CGRP-induced hyperpolarization were both markedly enhanced, consistent with the idea that opening of K channels underlies both responses. 6. The present findings provide direct electrophysiological evidence for a neurotransmitter role of CGRP, released from the peripheral endings of capsaicin-sensitive primary afferent neurones, in the guinea-pig ureter. The action of both exogenous and endogenous CGRP involves the activation of glibenclamide-sensitive (KATP) potassium channels.
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Affiliation(s)
- P Santicioli
- Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy
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17
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Maggi CA, Giuliani S. Calcitonin gene-related peptide (CGRP) regulates excitability and refractory period of the guinea pig ureter. J Urol 1994; 152:520-4. [PMID: 8015106 DOI: 10.1016/s0022-5347(17)32786-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Previous studies have indicated that calcitonin gene-related peptide (CGRP), released from the peripheral endings of capsaicin-sensitive primary afferent neurons, may play a role as an inhibitory transmitter in the guinea pig ureter. The aim of this study was to compare the effect of capsaicin desensitization and administration of a CGRP receptor antagonist on the excitability and refractory period of the guinea pig ureter to electrical field stimulation. Electrical field stimulation using a long (5 msec.) pulse width produced phasic contractions of the ureter which were unaffected by tetrodotoxin, that is, were produced through direct excitation of ureteral smooth muscle. Human alpha CGRP (1 to 10 nM.) produced a concentration-dependent transient suppression of the evoked contractions, and its effect was prevented by the CGRP receptor antagonist human alpha CGRP(8-37) (1 microM.). In vitro capsaicin pretreatment (10 microM. for 15 minutes) to block neuropeptide release from peripheral endings of sensory nerves or administration of the CGRP receptor antagonist enhanced the responsiveness of the guinea pig ureter to electrical stimulation. In control ureters, the application of two trains of electrical stimuli failed to produce a second contraction at intertrain intervals greater than 20 seconds. The intertrain interval required to obtain a second contraction averaging 50% of the amplitude of the first response (ITI50) of control ureters was about 50 seconds. In vitro capsaicin pretreatment or administration of the CGRP receptor antagonist reduced the refractory period of the ureter to electrical field stimulation: ITI50 averaged 8.8 and 9.1 seconds after capsaicin or CGRP antagonist pretreatment, respectively. These findings demonstrate that capsaicin pretreatment or blockade of CGRP receptors produced qualitatively and quantitatively similar excitatory effects on ureteral excitability and refractory period and are in general agreement with the idea that CGRP is a primary inhibitory transmitter in guinea pig ureter. Inhibition of motility by CGRP could be important for setting the frequency of ureteral peristalsis and suppression of latent pacemakers to prevent the occurrence of antiperistaltic waves.
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Affiliation(s)
- C A Maggi
- Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy
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18
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Maggi CA, Giuliani S. A thiorphan-sensitive mechanism regulates the action of both exogenous and endogenous calcitonin gene-related peptide (CGRP) in the guinea-pig ureter. REGULATORY PEPTIDES 1994; 51:263-71. [PMID: 7524118 DOI: 10.1016/0167-0115(94)90072-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The aim of this study was to assess the existence of mechanisms regulating the intensity and duration of action of calcitonin gene-related peptide (CGRP), the main candidate inhibitory transmitter released from capsaicin-sensitive afferents in the guinea-pig ureter. In a first series of experiments, performed in capsaicin-pretreated ureters, exogenously administered human alpha CGRP (h alpha CGRP) produced inhibition of contractions of the guinea-pig isolated ureter evoked by direct electrical stimulation of smooth muscle. The intensity and duration of the inhibitory effect of h alpha CGRP were potentiated by the inhibitor of neutral endopeptidase, thiorphan, while captopril and bestatin were without effect. In a second series of experiments, background motility of the guinea-pig ureter was evoked by administration of endothelin-1 (ET-1): electrical stimulation of intramural nerves produced a transient suppression of the ET-1-evoked contractions, ascribable to release of endogenous CGRP. Thiorphan enhanced the inhibitory effect produced by endogenous CGRP, while bestatin and captopril were without effect. These findings demonstrate that a thiorphan-sensitive mechanism, presumably neutral endopeptidase, regulates the intensity and duration of the inhibitory activity of both exogenous and endogenous CGRP in the guinea-pig ureter. The existence of a mechanisms for inactivation of the released peptide is consistent with the proposed role of CGRP as inhibitory neurotransmitter in this preparation.
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Affiliation(s)
- C A Maggi
- Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy
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Giuliani S, Santicioli P, Lippe IT, Lecci A, Maggi CA. Effect of bradykinin and tachykinin receptor antagonist on xylene-induced cystitis in rats. J Urol 1993; 150:1014-7. [PMID: 7688430 DOI: 10.1016/s0022-5347(17)35677-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of the bradykinin receptor selective antagonist, Hoe 140, and of the tachykinin NK-1 receptor antagonist (+/-)CP 96,345 were investigated in a rat model of chemically-induced cystitis (intravesical instillation of xylene in female rats). Intravenous injection of bradykinin (1 mumol./kg.) or substance P (3 nmol./kg.) produced plasma protein extravasation (PPE) in the rat urinary bladder. Bradykinin response was prevented by Hoe 140 (100 nmol./kg. intravenously) and unaffected by (+/-)CP 96,345 (10 mumol./kg. intravenously). Plasma protein extravasation produced by substance P was inhibited by (+/-)CP 96,345 but unchanged by Hoe 140. Catheterization required for intravesical xylene instillation into the female rat bladder produced per se an inflammatory response which was abolished by either Hoe 140 or (+/-)CP 96,345. Intravesical instillation of xylene produced a large PPE response which was reduced by about 65% by Hoe 140 or (+/-)CP 96,345. Combined administration of the two antagonists produced an additive effect on the PPE response to xylene. We conclude that both bradykinin and tachykinins are involved in the inflammatory reaction of the rat urinary bladder to catheterization and xylene irritation.
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Affiliation(s)
- S Giuliani
- Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy
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Maggi CA, Santicioli P, Del Bianco E, Lecci A, Guliani S. Evidence for the involvement of bradykinin in chemically-evoked cystitis in anaesthetized rats. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1993; 347:432-7. [PMID: 8389987 DOI: 10.1007/bf00165395] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The effect of Hoe 140, a potent bradykinin B2 receptor antagonist, on the micturition reflex and detrusor hyperreflexia induced by chemical cystitis has been investigated in anaesthetized rats. Hoe 140 (1-100 nmol/kg i.v.) produced a dose-dependent blockade of the contraction of the rat urinary bladder induced by i.v. administration of bradykinin (100 nmol/kg) without affecting the response produced by the selective tachykinin NK-1 receptor agonist, [Sar9] substance P (SP) sulfone (1 nmol/kg i.v.). At doses which produce selective and long-lasting blockade of bradykinin receptors in the urinary bladder, Hoe 140 did not modify urodynamic parameters in normal rats. Intravesical instillation of xylene in female rats decreased bladder capacity and increased micturition frequency. These effects also occurred in rats pretreated with capsaicin as adults. Hoe 140 did not modify xylene-induced cystitis. Intraperitoneal administration of cyclophosphamide (150 mg/kg, 48 h before) decreased bladder capacity and increased micturition frequency. These effects of cyclophosphamide were abolished in rats pretreated with capsaicin as adults. Hoe 140 increased bladder capacity and decreased micturition frequency in rats pretreated with cyclophosphamide. Addition of bradykinin (10 mumol/l) to the medium in the superfused rat urinary bladder preparation evoked a prompt increase in the outflow of calcitonin gene-related peptide like immunoreactivity (CGRP-LI). Hoe 140 (3 mumol/l) inhibited (by about 50%) the CGRP-LI out-flow stimulated by bradykinin. These findings demonstrate the participation of bradykinin, through B2 receptors, in the genesis of detrusor hyperreflexia during cyclophosphamide-induced cystitis.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C A Maggi
- Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy
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