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Mitsui R, Chikada Y, Arai K, Hashitani H. Functional nitrergic innervation of smooth muscle structures in the mucosa of pig lower urinary tract. Cell Tissue Res 2021; 386:513-531. [PMID: 34604930 DOI: 10.1007/s00441-021-03521-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/15/2021] [Indexed: 11/26/2022]
Abstract
Neurally released nitric oxide (NO) functions as an inhibitory neurotransmitter of urethral but not detrusor smooth muscles while relaxing bladder vasculature and muscularis mucosae (MM). Here, the distribution of nitrergic nerves was examined in the mucosa of pig lower urinary tract using immunohistochemistry, and their vasodilatory functions were studied by measuring arteriolar diameter changes. Properties of smooth muscle cells in the lamina propria (SMC-LP) of urethra and trigone were also investigated using florescence Ca2+ imaging. In the bladder mucosa, neuronal nitric oxide synthase (nNOS)-immunoreactive nitrergic fibres projected to suburothelial arterioles and venules. Perivascular nitrergic nerves were intermingled with but distinct from tyrosine hydroxylase (TH)-immunoreactive sympathetic or calcitonin gene-related peptide (CGRP)-immunoreactive afferent nerves. MM receive a nitrergic but not sympathetic or afferent innervation. In the mucosa of urethra and trigone, nitrergic nerves were in close apposition with sympathetic or afferent nerves around suburothelial vasculature but did not project to SMC-LP. In suburothelial arterioles of bladder and urethra, N ω-nitro-L-arginine (L-NA, 100 μM), an NOS inhibitor, enhanced electrical field stimulation (EFS)-induced sympathetic vasoconstrictions, while tadalafil (10 nM), a phosphodiesterase type 5 (PDE5) inhibitor, suppressed the vasoconstrictions. SMC-LP developed asynchronous spontaneous Ca2+ transients without responding to EFS. The spontaneous Ca2+ transients were enhanced by acetylcholine (1 μM) and diminished by noradrenaline (1 μM) but not SIN-1 (10 μM), an NO donor. In the lower urinary tract mucosa, perivascular nitrergic nerves appear to counteract the sympathetic vasoconstriction to maintain the mucosal circulation. Bladder MM but not SMC-LP receive an inhibitory nitrergic innervation.
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Affiliation(s)
- Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
| | - Yota Chikada
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Keiji Arai
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Tanaka H, Mitsui R, Oishi M, Passlick S, Jabs R, Steinhäuser C, Tanaka KF, Hashitani H. NO-mediated signal transmission in bladder vasculature as a therapeutic target of PDE5 inhibitors. Rodent model studies. Br J Pharmacol 2021; 178:1073-1094. [PMID: 33314051 DOI: 10.1111/bph.15342] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND AND PURPOSE While the bladder vasculature is considered as a target of PDE5 inhibitors to improve bladder storage dysfunctions, its characteristics are largely unknown. Thus, the functional and morphological properties of arteries/arterioles of the bladder focusing on the NO-mediated signal transmission were explored. EXPERIMENTAL APPROACH Diameter changes in rat bladder arteries/arterioles were measured using a video-tracking system. Intercellular Ca2+ dynamics in pericytes or smooth muscle cells (SMCs) of suburothelial arterioles were visualised using transgenic mice expressing GCaMP6 under control of the NG2- or parvalbumin-promoter. The perivascular innervation was investigated using fluorescence immunohistochemistry. KEY RESULTS In rat suburothelial arterioles and vesical arteries, tadalafil (100 nM) attenuated nerve-evoked sympathetic vasoconstrictions. In both vascular segments, tadalafil-induced inhibition of sympathetic vasoconstriction was prevented by N ω-propyl-l-arginine hydrochloride (l-NPA, 1 μM), an nNOS inhibitor or N ω-nitro-l-arginine (l-NA, 100 μM). Both vascular segments were densely innervated with nNOS-positive nitrergic nerves in close apposition to tyrosine hydroxylase-immunoreactive sympathetic nerves. In pericyte-covered pre-capillary arterioles of the mouse bladder where sympathetic nerves were absent, nerve stimulation evoked transient reductions in pericyte Ca2+ levels that were shortened by l-NPA and abolished by l-NA. In SMC-containing arterioles, tadalafil (10 nM) caused a l-NPA-sensitive suppression of sympathetic Ca2+ transients. In mice, nitrergic perivascular nerves were distributed in the arterioles and the pre-capillary arterioles. CONCLUSION AND IMPLICATIONS Both nitrergic nerve and nerve-evoked endothelial NO release appear to be involved in vasodilatory signal transmission in bladder vasculature. The NO-mediated signal transmission is a potential target for PDE5 inhibitor therapy in bladder dysfunctions.
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Affiliation(s)
- Hidekazu Tanaka
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Retsu Mitsui
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Mitsuhiro Oishi
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Stefan Passlick
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Ronald Jabs
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
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Mitsui R, Hashitani H. Synchrony of spontaneous Ca 2+ activity in microvascular mural cells. J Smooth Muscle Res 2020; 56:1-18. [PMID: 32249242 PMCID: PMC7132055 DOI: 10.1540/jsmr.56.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Spontaneous rhythmic constrictions known as vasomotion are developed in several microvascular beds in vivo. Vasomotion in arterioles is considered to facilitate blood flow, while venular vasomotion would facilitate tissue metabolite drainage. Mechanisms underlying vasomotion periodically generate synchronous Ca2+ transients in vascular smooth muscle cells (VSMCs). In visceral organs, mural cells (pericytes and VSMCs) in arterioles, capillaries and venules exhibit synchronous spontaneous Ca2+ transients. Since sympathetic regulation is rather limited in the intra-organ microvessels, spontaneous activity of mural cells may play an essential role in maintaining tissue perfusion. Synchronous spontaneous Ca2+ transients in precapillary arterioles (PCAs)/capillaries appear to propagate to upstream arterioles to drive their vasomotion, while venules develop their own synchronous Ca2+ transients and associated vasomotion. Spontaneous Ca2+ transients of mural cells primarily arise from IP3 and/or ryanodine receptor-mediated Ca2+ release from sarcoendoplasmic reticulum (SR/ER) Ca2+ stores. The resultant opening of Ca2+-activated Cl- channels (CaCCs) causes a membrane depolarisation that triggers Ca2+ influx via T-type and/or L-type voltage-dependent Ca2+ channels (VDCCs). Mural cells are electrically coupled with each other via gap junctions, and thus allow the sequential spread of CaCC or VDCC-dependent depolarisations to develop the synchrony of Ca2+ transients within their network. Importantly, the synchrony of spontaneous Ca2+ transients also requires a certain range of the resting membrane potential that is maintained by the opening of Kv7 voltage-dependent K+ (Kv7) and inward rectifier K+ (Kir) channels. Thus, a depolarised membrane would evoke asynchronous, 'premature' spontaneous Ca2+ transients, while a hyperpolarised membrane prevents any spontaneous activity.
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Affiliation(s)
- Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
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Tykocki NR, Monson FC. Excitability and contractility in arterioles and venules from the urinary bladder. CURRENT TOPICS IN MEMBRANES 2020; 85:301-326. [DOI: 10.1016/bs.ctm.2020.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Nguyen NM, Song KM, Choi MJ, Ghatak K, Limanjaya A, Kwon MH, Chung DY, Ock J, Yin GN, Park CS, Suh JK, Ryu JK. Three-Dimensional Reconstruction of Neurovascular Network in Whole Mount Preparations and Thick-Cut Transverse Sections of Mouse Urinary Bladder. World J Mens Health 2019; 39:131-138. [PMID: 31496149 PMCID: PMC7752506 DOI: 10.5534/wjmh.190089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/01/2019] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Proper functional and structural integrity of nervous and vascular system in urinary bladder plays an important role in normal bladder function and the disruption of these structures is known to be related to lower urinary tract symptoms. Here, we present an immunohistochemical staining method that delineates neurovascular structures in the mouse urinary bladder by using immunohistochemical staining with three-dimensional reconstruction. MATERIALS AND METHODS The urinary bladder was harvested from 8-week-old C57BL/6 male mouse. Lamina propria and detrusor muscle layer were dissected for whole mount staining, and thick-cut (60-μm) sections were prepared for full-thickness bladder staining. Immunofluorescent staining of bladder tissue was performed with antibodies against CD31 (an endothelial cell marker), smooth muscle α-actin (a smooth muscle cell marker), NG2 (a pericyte marker), and βIII-tubulin (a neuronal marker). We reconstructed three-dimensional images of bladder neurovascular system from stacks of two-dimensional images. RESULTS Three-dimensional images obtained from thick-cut sections clearly provided good anatomic information about neurovascular structures in the three layers of bladder, such as urothelium, lamina propria, and detrusor muscle layer. Whole mount images of lamina propria and detrusor muscle layer also clearly delineated spatial relationship between nervous and vascular systems. The microvessel density was higher in the lamina propria than in the detrusor muscle layer. Nerve fibers were evenly innervated into the lamina propria and detrusor muscle. CONCLUSIONS This study provides comprehensive insight into three-dimensional neurovascular structures of mouse urinary bladder. Our technique may constitute a standard tool to evaluate pathologic changes in a variety of urinary bladder diseases.
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Affiliation(s)
- Nhat Minh Nguyen
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Kang Moon Song
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Min Ji Choi
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Kalyan Ghatak
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Anita Limanjaya
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Mi Hye Kwon
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Doo Yong Chung
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Jiyeon Ock
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Guo Nan Yin
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea
| | - Chang Shin Park
- Department of Pharmacology and Medicinal Toxicology Research Center, Inha University School of Medicine, Incheon, Korea
| | - Jun Kyu Suh
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea.
| | - Ji Kan Ryu
- National Research Center for Sexual Medicine and Department of Urology, Inha University School of Medicine, Incheon, Korea.
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Mitsui R, Lee K, Uchiyama A, Hayakawa S, Kinoshita F, Kajioka S, Eto M, Hashitani H. Contractile elements and their sympathetic regulations in the pig urinary bladder: a species and regional comparative study. Cell Tissue Res 2019; 379:373-387. [PMID: 31446446 DOI: 10.1007/s00441-019-03088-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022]
Abstract
Contractile behaviour of the urinary bladder and its sympathetic inhibition during storage phases are not well understood. Here, we explore muscularis mucosae (MM) as a predominant mucosal contractile element and the capability of sympathetic nerves to relax detrusor smooth muscle (DSM) or MM. Distribution of α-smooth muscle actin (α-SMA)-immunoreactive cells was compared in pig, human, guinea pig, rat and mouse bladders by immunohistochemistry, while contractility of the bladder mucosa was compared in these species by isometric tension recordings. In pig, human and guinea pig bladders, DSM and MM located in the lamina propria expressed α-SMA immunoreactivity, while both rat and mouse bladders lacked a MM. Consistent with this presence or absence of MM, bladder mucosa of pig, human and guinea pig but not rat and mouse developed spontaneous phasic contractions (SPCs). Distribution of tyrosine hydroxylase (TH)-immunoreactive sympathetic nerve fibres was compared in pig DSM, MM, trigone and urethra, as were their sympathetic nerve-evoked contractile/relaxing responses examined. In pig DSM or MM, where TH-immunoreactive sympathetic fibres exclusively projected to the vasculature, sympathetic relaxations were difficult to demonstrate. In contrast, sympathetic contractions were invariably evoked in pig trigone and urethra where the smooth muscle cells receive TH-immunoreactive sympathetic innervations. Thus, SPCs of bladder mucosa appear to predominantly arise from the MM displaying species differences. Despite the currently accepted concept of sympathetic nerve-mediated DSM relaxation during the storage phase, it is unlikely that neurally released noradrenaline acts on β-adrenoceptors to relax either DSM or MM due to the anatomical lack of sympathetic innervation.
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Affiliation(s)
- Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan.
| | - Ken Lee
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Aoi Uchiyama
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan
| | - Shunta Hayakawa
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan
| | - Fumio Kinoshita
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shunichi Kajioka
- Department of Applied Urology and Molecular Medicine, Kyushu University, Fukuoka, Japan
| | - Masatoshi Eto
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan
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Role of Pericytes in the Initiation and Propagation of Spontaneous Activity in the Microvasculature. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:329-356. [PMID: 31183834 DOI: 10.1007/978-981-13-5895-1_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The microvasculature is composed of arterioles, capillaries and venules. Spontaneous arteriolar constrictions reduce effective vascular resistance to enhance tissue perfusion, while spontaneous venular constrictions facilitate the drainage of tissue metabolites by pumping blood. In the venules of visceral organs, mural cells, i.e. smooth muscle cells (SMCs) or pericytes, periodically generate spontaneous phasic constrictions, Ca2+ transients and transient depolarisations. These events arise from spontaneous Ca2+ release from the sarco-endoplasmic reticulum (SR/ER) and the subsequent opening of Ca2+-activated chloride channels (CaCCs). CaCC-dependent depolarisation further activates L-type voltage-dependent Ca2+ channels (LVDCCs) that play a critical role in maintaining the synchrony amongst mural cells. Mural cells in arterioles or capillaries are also capable of developing spontaneous activity. Non-contractile capillary pericytes generate spontaneous Ca2+ transients primarily relying on SR/ER Ca2+ release. Synchrony amongst capillary pericytes depends on gap junction-mediated spread of depolarisations resulting from the opening of either CaCCs or T-type VDCCs (TVDCCs) in a microvascular bed-dependent manner. The propagation of capillary Ca2+ transients into arterioles requires the opening of either L- or TVDCCs again depending on the microvascular bed. Since the blockade of gap junctions or CaCCs prevents spontaneous Ca2+ transients in arterioles and venules but not capillaries, capillary pericytes appear to play a primary role in generating spontaneous activity of the microvasculature unit. Pericytes in capillaries where the interchange of substances between tissues and the circulation takes place may provide the fundamental drive for upstream arterioles and downstream venules so that the microvasculature network functions as an integrated unit.
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Abstract
Microcirculation is the generic name for the finest level of the circulatory system and consists of arteriolar and venular networks located upstream and downstream of capillaries, respectively. Anatomically arterioles are surrounded by a monolayer of spindle-shaped smooth muscle cells (myocytes), while terminal branches of precapillary arterioles, capillaries and all sections of postcapillary venules are surrounded by a monolayer of morphologically different perivascular cells (pericytes). Pericytes are essential components of the microvascular vessel wall. Wrapped around endothelial cells, they occupy a strategic position at the interface between the circulating blood and the interstitial space. There are physiological differences in the responses of pericytes and myocytes to vasoactive molecules, which suggest that these two types of vascular cells could have different functional roles in the regulation of local blood flow within the same microvascular bed. Also, pericytes may play different roles in different microcirculatory beds to meet the characteristics of individual organs. Contractile activity of pericytes and myocytes is controlled by changes of cytosolic free Ca2+concentration. In this chapter, we attempt to summarize the results in the field of Ca2+ signalling in pericytes especially in light of their contractile roles in different tissues and organs. We investigate the literature and describe our results regarding sources of Ca2+, relative importance and mechanisms of Ca2+ release and Ca2+ entry in control of the spatio-temporal characteristics of the Ca2+ signals in pericytes, where possible Ca2+ signalling and contractile responses in pericytes are compared to those of myocytes.
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Hashitani H, Mitsui R, Miwa-Nishimura K, Lam M. Role of capillary pericytes in the integration of spontaneous Ca 2+ transients in the suburothelial microvasculature in situ of the mouse bladder. J Physiol 2018; 596:3531-3552. [PMID: 29873405 DOI: 10.1113/jp275845] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/21/2018] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS In the bladder suburothelial microvasculature, pericytes in different microvascular segments develop spontaneous Ca2+ transients with or without associated constrictions. Spontaneous Ca2+ transients in pericytes of all microvascular segments primarily rely on the cycles of Ca2+ uptake and release by the sarco- and endoplasmic reticulum. The synchrony of spontaneous Ca2+ transients in capillary pericytes exclusively relies on the spread of depolarizations resulting from the opening of Ca2+ -activated chloride channels (CaCCs) via gap junctions. CaCC-dependent depolarizations further activate L-type voltage-dependent Ca2+ channels as required for the synchrony of Ca2+ transients in pericytes of pre-capillary arterioles, post-capillary venules and venules. Capillary pericytes may drive spontaneous Ca2+ transients in pericytes within the suburothelial microvascular network by sending CaCC-dependent depolarizations via gap junctions. ABSTRACT Mural cells in the microvasculature of visceral organs develop spontaneous Ca2+ transients. However, the mechanisms underlying the integration of these Ca2+ transients within a microvascular unit remain to be clarified. In the present study, the origin of spontaneous Ca2+ transients and their propagation in the bladder suburothelial microvasculature were explored. Cal-520 fluorescence Ca2+ imaging and immunohistochemistry were carried out on mural cells using mice expressing red fluorescent protein (DsRed) under control of the NG2 promotor. NG2(+) pericytes in both pre-capillary arterioles (PCAs) and capillaries developed synchronous spontaneous Ca2+ transients. By contrast, although NG2-DsRed also labelled arteriolar smooth muscle cells, these cells remained quiescent. Both NG2(+) pericytes in post-capillary venules (PCVs) and NG2(-) venular pericytes exhibited propagated Ca2+ transients. L-type voltage-dependent Ca2+ channel (LVDCC) blockade with nifedipine prevented Ca2+ transients or disrupted their synchrony in PCA, PCV and venular pericytes without dis-synchronizing Ca2+ transients in capillary pericytes. Blockade of gap junctions with carbenoxolone or Ca2+ -activated chloride channels (CaCCs) with 4,4'-diisothiocyanato-2,2'-stilbenedisulphonic acid disodium salt prevented Ca2+ transients in PCA and venular pericytes and disrupted the synchrony of Ca2+ transients in capillary and PCV pericytes. Spontaneous Ca2+ transients in pericytes of all microvascular segments were abolished or suppressed by cyclopiazonic acid, caffeine or tetracaine. The synchrony of Ca2+ transients in capillary pericytes arising from spontaneous Ca2+ release from the sarco- and endoplasmic reticulum appears to rely exclusively on CaCC activation, whereas subsequent LVDCC activation is required for the synchrony of Ca2+ transients in pericytes of other microvascular segments. Capillary pericytes may drive spontaneous activity in the suburothelial microvascular unit to facilitate capillary perfusion.
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Affiliation(s)
- Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Retsu Mitsui
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Kyoko Miwa-Nishimura
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Michelle Lam
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
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Fukuta H, Mitsui R, Takano H, Hashitani H. Contractile properties of periosteal arterioles in the guinea-pig tibia. Pflugers Arch 2017; 469:1203-1213. [PMID: 28466243 DOI: 10.1007/s00424-017-1980-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/05/2017] [Accepted: 04/09/2017] [Indexed: 11/30/2022]
Abstract
The periosteal arterioles of the compact bone may play a critical role in bone growth. To explore the contractile properties of tibial arterioles, spontaneous and nerve-evoked constrictions were compared in preparations from 3-week-old and 1-year-old guinea-pigs. Changes in arteriole diameters were measured using video microscopy. Their innervation was investigated using fluorescence immunohistochemistry. Fifty per cent and 40% of tibial arterioles from 3-week-old and 1-year-old guinea-pigs, respectively, exhibited spontaneous phasic constrictions that were inhibited by 1 μM nifedipine, 10 μM cyclopiazonic acid or 100 μM 2-APB. Nerve-evoked phasic constrictions in both age groups were largely suppressed by phentolamine (1 μM), an α-adrenoceptor antagonist, or sympathetic neurotransmitter depletion using guanethidine (10 μM) but were enhanced by spanttide (1 μM), a substance P receptor antagonist, or L-nitro arginine (L-NA; 100 μM), an inhibitor of nitric oxide synthase (NOS). Nerve-evoked constrictions in 1-year-old animals were smaller than those in younger animals but greatly enhanced by L-NA. Immunohistochemistry revealed sympathetic and substance P-positive primary afferent nerves running along the arterioles as well as endothelial NOS expression in both age groups. Spontaneous arteriolar constrictions appear to rely on both Ca2+ release from the sarcoplasmic reticulum and Ca2+ influx through L-type Ca2+ channels. Noradrenaline released from sympathetic nerves triggers arteriolar constriction, while substance P released from primary afferent nerves dilates the arterioles by releasing nitric oxide (NO), presumably from the endothelium. Thus, the enhanced endothelial NO release in adult guinea-pigs may be important to increase the blood supply to meet the increased metabolic demands during bone growth.
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Affiliation(s)
- Hiroyasu Fukuta
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-Ku, Nagoya, 467-8601, Japan.
| | - Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-Ku, Nagoya, 467-8601, Japan
| | - Hiromichi Takano
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-Ku, Nagoya, 467-8601, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-Ku, Nagoya, 467-8601, Japan
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Mitsui R, Hashitani H. Properties of synchronous spontaneous Ca 2+ transients in the mural cells of rat rectal arterioles. Pflugers Arch 2017; 469:1189-1202. [PMID: 28429070 DOI: 10.1007/s00424-017-1978-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/20/2017] [Accepted: 04/05/2017] [Indexed: 10/19/2022]
Abstract
Synchrony of spontaneous Ca2+ transients among venular mural cells (smooth muscle cells and pericytes) in visceral organs relies on the intercellular spread of L-type voltage-dependent Ca2+ channel (LVDCC)-dependent depolarisations. However, the mechanisms underlying the synchrony of spontaneous Ca2+ transients between arteriolar mural cells are less understood. The spontaneous intracellular Ca2+ dynamics of arteriolar mural cells in the rat rectal submucosa were visualised by Cal-520 Ca2+ imaging to analyse their synchrony. The mural cells in fine arterioles that had a rounded cell body with several extended processes developed spontaneous 'synchronous' Ca2+ transients arising from Ca2+ released from sarcoendoplasmic reticulum Ca2+ stores. Gap junction blockers (3 μM carbenoxolone, 10 μM 18β-glycyrrhetinic acid), a Ca2+-activated Cl- channel (CaCC) blocker (100 μM 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid) or lowering extracellular Cl- concentration (from 134.4 to 12.4 mM) disrupted the synchrony of Ca2+ transients between arteriolar mural cells. Blockers of T-type voltage-dependent Ca2+ channels (TVDCCs, 1 μM mibefradil or ML218) or LVDCCs (1 μM nifedipine) reduced the Ca2+ transient frequency or their area under curve (AUC), respectively. However, neither TVDCC nor LVDCC blockers disrupted the synchrony of Ca2+ transients among arteriolar mural cells. This is in contrast with rectal venules in which nifedipine disrupted the synchrony of spontaneous Ca2+ transients. Thus, spontaneous transient depolarisations arising from the opening of CaCCs may effectively spread to neighbouring arteriolar mural cells via gap junctions to maintain the Ca2+ transient synchrony. Activation of TVDCCs appears to accelerate spontaneous Ca2+ transients, while LVDCCs predominantly contribute to the duration of Ca2+ transients.
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Affiliation(s)
- Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-Ku, Nagoya, 467-8601, Japan.
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-Ku, Nagoya, 467-8601, Japan
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Tykocki NR, Bonev AD, Longden TA, Heppner TJ, Nelson MT. Inhibition of vascular smooth muscle inward-rectifier K + channels restores myogenic tone in mouse urinary bladder arterioles. Am J Physiol Renal Physiol 2017; 312:F836-F847. [PMID: 28148533 DOI: 10.1152/ajprenal.00682.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/18/2017] [Accepted: 01/26/2017] [Indexed: 01/25/2023] Open
Abstract
Prolonged decreases in urinary bladder blood flow are linked to overactive and underactive bladder pathologies. However, the mechanisms regulating bladder vascular reactivity are largely unknown. To investigate these mechanisms, we examined myogenic and vasoactive properties of mouse bladder feed arterioles (BFAs). Unlike similar-sized arterioles from other vascular beds, BFAs failed to constrict in response to increases in intraluminal pressure (5-80 mmHg). Consistent with this lack of myogenic tone, arteriolar smooth muscle cell membrane potential was hyperpolarized (-72.8 ± 1.4 mV) at 20 mmHg and unaffected by increasing pressure to 80 mmHg (-74.3 ± 2.2 mV). In contrast, BFAs constricted to the thromboxane analog U-46619 (100 nM), the adrenergic agonist phenylephrine (10 µM), and KCl (60 mM). Inhibition of nitric oxide synthase or intermediate- and small-conductance Ca2+-activated K+ channels did not alter arteriolar diameter, indicating that the dilated state of BFAs is not attributable to overactive endothelium-dependent dilatory influences. Myocytes isolated from BFAs exhibited BaCl2 (100 µM)-sensitive K+ currents consistent with strong inward-rectifier K+ (KIR) channels. Notably, block of these KIR channels "restored" pressure-induced constriction and membrane depolarization. This suggests that these channels, in part, account for hyperpolarization and associated absence of tone in BFAs. Furthermore, smooth muscle-specific knockout of KIR2.1 caused significant myogenic tone to develop at physiological pressures. This suggests that 1) the regulation of vascular tone in the bladder is independent of pressure, insofar as pressure-induced depolarizing conductances cannot overcome KIR2.1-mediated hyperpolarization; and 2) maintenance of bladder blood flow during bladder filling is likely controlled by neurohumoral influences.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and
| | - Adrian D Bonev
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and
| | - Thomas A Longden
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and
| | - Thomas J Heppner
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and
| | - Mark T Nelson
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and.,Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
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Andersson KE, Boedtkjer DB, Forman A. The link between vascular dysfunction, bladder ischemia, and aging bladder dysfunction. Ther Adv Urol 2016; 9:11-27. [PMID: 28042309 DOI: 10.1177/1756287216675778] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The vascular supply to the human bladder is derived mainly from the superior and inferior vesical arteries, the latter being directly connected to the internal iliac artery. Aging is associated with an impairment of blood vessel function and changes may occur in the vasculature at the molecular, cellular and functional level. Pelvic arterial insufficiency may play an important role in the development of bladder dysfunctions such as detrusor overactivity (DO) and the overactive bladder syndrome. Chronic ischemia-related bladder dysfunction may progress to bladder underactivity and it would be desirable to treat not only lower urinary tract symptoms (LUTS) induced by chronic ischemia, but also the progression of the morphological bladder changes. Studies in experimental models in rabbits and rats have shown that pelvic arterial insufficiency may result in significant bladder ischemia with reduced bladder wall oxygen tension. In turn, this will lead to oxidative stress associated with upregulation of oxidative stress-sensitive genes, increased muscarinic receptor activity, ultrastructural damage, and neurodegeneration. The phosphodiesterase type 5 (PDE5) inhibitor tadalafil, the α1-adrenoceptor (AR) blocker silodosin, the β3-AR agonist mirabegron, and the free radical scavenger melatonin, exerted a protecting effect on urodynamic parameters, and on functional and morphological changes of the bladder demonstrable in vitro. Since the agents tested are used clinically for relieving LUTS, the results from the animal models seem to have translational value, and may be of relevance for designing clinical studies to demonstrate if the drugs may prevent progression of ischemia-related functional and morphological bladder changes.
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Affiliation(s)
- Karl-Erik Andersson
- Institute of Clinical Medicine, Department of Obstetrics and Gynecology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK 8200 Aarhus N, Denmark
| | | | - Axel Forman
- Department of Gynecology and Obstetrics, Aarhus University Hospital, Denmark
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14
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Role of PTHrP and Sensory Nerve Peptides in Regulating Contractility of Muscularis Mucosae and Detrusor Smooth Muscle in the Guinea Pig Bladder. J Urol 2016; 196:1287-94. [DOI: 10.1016/j.juro.2016.04.082] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2016] [Indexed: 10/24/2022]
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15
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Hashitani H, Lang RJ. Spontaneous activity in the microvasculature of visceral organs: role of pericytes and voltage-dependent Ca(2+) channels. J Physiol 2016; 594:555-65. [PMID: 26607499 DOI: 10.1113/jp271438] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/31/2015] [Indexed: 12/21/2022] Open
Abstract
The microvasculature plays a primary role in the interchange of substances between tissues and the circulation. In visceral organs that undergo considerable distension upon filling, the microvasculature appears to display intrinsic contractile properties to maintain their flow. Submucosal venules in the bladder or gastrointestinal tract generate rhythmic spontaneous phasic constrictions and associated Ca(2+) transients. These events are initiated within either venular pericytes or smooth muscle cells (SMCs) arising from spontaneous Ca(2+) release from the sarcoplasmic reticulum (SR) and the opening of Ca(2+) -activated chloride channels (CaCCs) that trigger Ca(2+) influx through L-type voltage-dependent Ca(2+) channels (VDCCs). L-type VDCCs also play a critical role in maintaining synchrony within the contractile mural cells. In the stomach myenteric layer, spontaneous Ca(2+) transients originating in capillary pericytes appear to spread to their neighbouring arteriolar SMCs. Capillary Ca(2+) transients primarily rely on SR Ca(2+) release, but also require Ca(2+) influx through T-type VDCCs for their synchrony. The opening of T-type VDCCs also contribute to the propagation of Ca(2+) transients into SMCs. In visceral microvasculature, pericytes act as either spontaneously active contractile machinery of the venules or as pacemaker cells generating synchronous Ca(2+) transients that drive spontaneous contractions in upstream arterioles. Thus pericytes play different roles in different vascular beds in a manner that may well depend on the selective expression of T-type and L-type Ca(2+) channels.
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Affiliation(s)
- Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Richard J Lang
- Department of Physiology, School of Biomedical Sciences, Monash University, Clayton, Victoria, 3800, Australia
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16
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Mechanisms underlying spontaneous constrictions of postcapillary venules in the rat stomach. Pflugers Arch 2015; 468:279-91. [PMID: 26530829 DOI: 10.1007/s00424-015-1752-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 10/22/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022]
Abstract
Postcapillary venules (PCVs) play a critical role in regulating capillary hydrostatic pressure, but their contractile mechanisms are not well understood. We examined the properties of spontaneous vasomotion and corresponding Ca(2+) transients in gastric PCV. In the rat gastric submucosa, changes in PCV diameter and intracellular Ca(2+) dynamics were visualised by video tracking system and fluorescent Ca(2+) imaging, respectively, while PCV morphology was examined by immunohistochemistry. Stellate-shaped PCV mural cells expressing α-smooth muscle actin exhibited synchronised spontaneous Ca(2+) transients to develop vasomotion which was abolished by nifedipine (1 μM), cyclopiazonic acid (10 μM), or Ca(2+)-activated Cl(-) channel inhibitors (100 μM niflumic acid, 1 μM T16Ainh-A01). A gap junction blocker (3 μM carbenoxolone) disrupted the synchrony of spontaneous Ca(2+) transients amongst PCV mural cells and attenuated spontaneous vasomotion. Low chloride solution ([Cl(-)]0 = 12.4 mM) also disrupted the synchrony of spontaneous Ca(2+) transients and abolished vasomotion. Na(+)-K(+)-Cl(-) co-transporter inhibitors (10 μM bumetanide, 30 μM furosemide) suppressed spontaneous Ca(2+) transients and vasoconstrictions. A phosphodiesterase type 5 (PDE5) inhibitor (1 μM tadalafil) disrupted the spontaneous Ca(2+) transient synchrony and abolished vasomotion in a nitric oxide (NO)-dependent manner. Thus, gastric PCVs exhibit spontaneous vasomotion, resulting from synchronised spontaneous Ca(2+) transients within a network of stellate-shaped PCV mural cells. An active Cl(-) accumulation partly via Na(+)-K(+)-Cl(-) co-transport appears to be fundamental in maintaining depolarisation upon the opening of Ca(2+)-activated Cl(-) channels that triggers Ca(2+) influx via voltage-dependent L-type Ca(2+) channels. Basal PDE5 activity may continuously counteract vaso-relaxing effects of endothelial NO to maintain spontaneous vasomotion.
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17
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Chai TC, Russo A, Yu S, Lu M. Mucosal signaling in the bladder. Auton Neurosci 2015; 200:49-56. [PMID: 26422993 DOI: 10.1016/j.autneu.2015.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 08/27/2015] [Indexed: 01/09/2023]
Abstract
The bladder mucosa is comprised of the multilayered urothelium, lamina propria (LP), microvasculature, and smooth muscle fibers (muscularis mucosae). The muscularis mucosae is not always present in the mucosa, and its presence is related to the thickness of the LP. Since there are no mucus secreting cells, "mucosa" is an imprecise term. Nerve fibers are present in the LP of the mucosa. Efferent nerves mediate mucosal contractions which can be elicited by electrical field stimulation (EFS) and various agonists. The source of mucosal contractility is unknown, but may arise from the muscularis mucosae or myofibroblasts. EFS also increases frequency of mucosal venule contractions. Thus, efferent neural activity has multiple effects on the mucosa. Afferent activity has been measured when the mucosa is stimulated by mechanical and stretch stimuli from the luminal side. Nerve fibers have been shown to penetrate into the urothelium, allowing urothelial cells to interact with nerves. Myofibroblasts are specialized cells within the LP that generate spontaneous electrical activity which then can modulate both afferent and efferent neural activities. Thus mucosal signaling is defined as interactions between bladder autonomic nerves with non-neuronal cells within the mucosa. Mucosal signaling is likely to be involved in clinical functional hypersensory bladder disorders (e.g. overactive bladder, urgency, urgency incontinence, bladder pain syndrome) in which mechanisms are poorly understood despite high prevalence of these conditions. Targeting aberrant mucosal signaling could represent a new approach in treating these disorders.
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Affiliation(s)
- Toby C Chai
- Department of Urology, United States; Department of Obstetrics, Gynecology and Reproductive Science, Yale School of Medicine, New Haven, CT, United States.
| | - Andrea Russo
- Department of Obstetrics, Gynecology and Reproductive Science, Yale School of Medicine, New Haven, CT, United States
| | - Shan Yu
- Department of Urology, United States
| | - Ming Lu
- Department of Urology, United States
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Hashitani H, Mitsui R, Masaki S, Van Helden DF. Pacemaker role of pericytes in generating synchronized spontaneous Ca2+ transients in the myenteric microvasculature of the guinea-pig gastric antrum. Cell Calcium 2015; 58:442-56. [PMID: 26153078 DOI: 10.1016/j.ceca.2015.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/08/2015] [Accepted: 06/28/2015] [Indexed: 11/25/2022]
Abstract
Properties of spontaneous Ca(2+) transients in the myenteric microvasculature of the guinea-pig stomach were investigated. Specifically, we explored the spatio-temporal origin of Ca(2+) transients and the role of voltage-dependent Ca(2+) channels (VDCCs) in their intercellular synchrony using fluorescence Ca(2+) imaging and immunohistochemistry. The microvasculature generated spontaneous Ca(2+) transients that were independent of both Ca(2+) transients in interstitial cells of Cajal (ICC) and neural activity. Spontaneous Ca(2+) transients were highly synchronous along the length of microvasculature, and appeared to be initiated in pericytes and spread to arteriolar smooth muscle cells (SMCs). In most cases, the generation or synchrony of Ca(2+) transients was not affected by blockers of L-type VDCCs. In nifedipine-treated preparations, synchronous spontaneous Ca(2+) transients were readily blocked by Ni(2+), mibefradil or ML216, blockers for T-type VDCCs. These blockers also suppressed the known T-type VDCC dependent component of ICC Ca(2+) transients or slow waves. Spontaneous Ca(2+) transients were also suppressed by caffeine, tetracaine or cyclopiazonic acid (CPA). After the blockade of both L- and T-type VDCCs, asynchronous Ca(2+) transients were generated in pericytes on precapillary arterioles and/or capillaries but not in arteriolar SMCs, and were abolished by CPA or nominally Ca(2+) free solution. Together these data indicate that pericytes in the myenteric microvasculature may act as the origin of synchronous spontaneous Ca(2+) transients. Pericyte Ca(2+) transients arise from Ca(2+) release from the sarco-endoplasmic reticulum and the opening of T-type Ca(2+) VDCCs is required for their synchrony and propagation to arteriolar SMCs.
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Affiliation(s)
- Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.
| | - Retsu Mitsui
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Shota Masaki
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Dirk F Van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle, NSW, Australia
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Mitsui R, Miyamoto S, Takano H, Hashitani H. Properties of submucosal venules in the rat distal colon. Br J Pharmacol 2014; 170:968-77. [PMID: 23992146 DOI: 10.1111/bph.12347] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/06/2013] [Accepted: 06/21/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Venules within the gut wall may have intrinsic mechanisms for maintaining the circulation even upon the intestinal wall distension. We aimed to explore spontaneous and nerve-mediated contractile activity of colonic venules. EXPERIMENTAL APPROACH Changes in the diameter of submucosal venules of the rat distal colon were measured using video microscopy. The innervation of the microvasculature was investigated using fluorescence immunohistochemistry. KEY RESULTS Submucosal venules exhibited spontaneous constrictions that were abolished by blockers of L-type Ca(2+) channels (1 μM nicardipine), Ca(2+)-ATPase (10 μM cyclopiazonic acid), IP3 receptor (100 μM 2-APB), Ca(2+)-activated Cl(-) channels (100 μM DIDS) or store-operated Ca(2+) entry channels (10 μM SKF96365). Transmural nerve stimulation (TNS at 10 Hz) induced a phasic venular constriction that was blocked by phentolamine (1 μM, α-adrenoceptor antagonist) or sympathetic nerve depletion using guanethidine (10 μM). Stimulation of primary afferent nerves with TNS (at 20 Hz) or capsaicin (100 nM) evoked a sustained venular dilatation that was attenuated by calcitonin gene-related peptide (CGRP) 8-37 (2 μM), a CGRP receptor antagonist. Immunohistochemistry revealed sympathetic and primary afferent nerves running along submucosal venules. CONCLUSIONS AND IMPLICATIONS Submucosal venules of the rat distal colon exhibit spontaneous constrictions that appear to primarily rely on Ca(2+) release from sarcoplasmic reticulum and subsequent opening of Ca(2+)-activated Cl(-) channels that trigger Ca(2+) influx through L-type Ca(2+) channels. Venular contractility is modulated by sympathetic as well as CGRP-containing primary afferent nerves, suggesting that submucosal venules may play an active role in regulating the microcirculation of the digestive tract.
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Affiliation(s)
- Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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20
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Functional properties of submucosal venules in the rat stomach. Pflugers Arch 2014; 467:1327-42. [PMID: 25066613 DOI: 10.1007/s00424-014-1576-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 06/12/2014] [Accepted: 07/04/2014] [Indexed: 10/25/2022]
Abstract
Venules in the stomach may have intrinsic properties for maintaining active microcirculation drainage even during gastric filling. Properties of spontaneous and nerve-mediated activity of submucosal venules in the rat stomach were investigated. Changes in vasodiameter and intracellular Ca(2+) in venular smooth muscle cells (SMCs) were monitored by video tracking and Fluo-8 Ca(2+) imaging, respectively. Venular SMCs developed synchronous spontaneous Ca(2+) transients and corresponding rhythmic constrictions of the venules. Nominally Ca(2+)-free solution or an L-type Ca(2+) channel blocker (1 μM nifedipine) disrupted the Ca(2+) transient synchrony and abolished spontaneous constrictions. Spontaneous constrictions were also prevented by inhibitors of sarcoplasmic reticulum Ca(2+)-ATPase (10 μM cyclopiazonic acid (CPA)), IP3 receptors (100 μM 2-APB) or Ca(2+)-activated Cl(-) channels (100 μM niflumic acid). Transmural nerve stimulation (TNS) induced a long-lasting venular constriction that was abolished by α-adrenoceptor antagonist (1 μM phentolamine), while TNS evoked a sympathetic transient constriction of arterioles that was abolished by a combination of phentolamine and a P2 purinoceptor antagonist (10 μM pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS)). Consistently, P2X1 purinoceptor immunoreactivity was detected in arteriolar but not venular SMCs. Primary afferent nerve stimulation (300 nM capsaicin) caused a venular dilatation by releasing calcitonin gene-related peptide. Thus, Ca(2+) release from the sarcoplasmic reticulum may play a fundamental role in the generation of spontaneous Ca(2+) transients, while electrical coupling amongst venular SMCs via L-type Ca(2+) channel activation appears to be critical for Ca(2+) transient synchrony as well as spontaneous contractions. Sympathetic venular constrictions appear to be exclusively mediated by noradrenaline due to the lack of P2X1 receptor in venular SMCs.
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21
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Burdyga T, Borysova L. Calcium signalling in pericytes. J Vasc Res 2014; 51:190-9. [PMID: 24903335 DOI: 10.1159/000362687] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/06/2014] [Indexed: 11/19/2022] Open
Abstract
Recent advances in pericyte research have contributed to our understanding of the physiology and pathophysiology of microvessels. The microvasculature consists of arteriolar and venular networks located upstream and downstream of the capillaries. Arterioles are surrounded by a monolayer of spindle-shaped myocytes, while terminal branches of precapillary arterioles, capillaries and all sections of postcapillary venules are encircled by a monolayer of morphologically diverse pericytes. There are physiological differences in the response of pericytes and myocytes to vasoactive molecules, suggesting that these two vascular cell types could have different functional roles in the regulation of local blood flow. The contractile activity of pericytes and myocytes is controlled by changes of cytosolic free Ca(2+) concentration. In this short review, we summarize our results and those of other authors on the contractility of pericytes and their Ca(2+) signalling. We describe results regarding sources of Ca(2+) and mechanisms of Ca(2+) release and Ca(2+) entry in control of the spatiotemporal characteristics of the Ca(2+) signals in pericytes.
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Affiliation(s)
- Theodor Burdyga
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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22
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Schueth A, van Zandvoort MAMJ, Buurman WA, van Koeveringe GA. Murine bladder imaging by 2-photon microscopy: an experimental study of morphology. J Urol 2014; 192:973-80. [PMID: 24704014 DOI: 10.1016/j.juro.2014.03.103] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 12/13/2022]
Abstract
PURPOSE We developed 2-photon laser scanning microscopy analysis of the native murine bladder. MATERIALS AND METHODS Bladder tissue from wild-type mice was imaged by 2-photon laser scanning microscopy autofluorescence and second harmonic generation microscopy. Bladder wall layers and structures were analyzed using differences in color, size, shape and morphology. RESULTS Autofluorescence of the urothelium, nerve structures and muscles was visible in the green spectral channel due to autofluorochromes such as NAD(P)H and elastin. Second harmonic generation of collagen was seen in the blue spectral channel. Imaging from the mucosal side revealed umbrella cells at 0 and 30 μm, of which the high cellular NAD(P)H content allows autofluorescence detection. Below that a network-like connective tissue layer was visualized up to 50 μm that contained vessels with a diameter of 10 to 40 μm and nerves with a diameter of 1 to 6 μm. Imaging from the adventitial side revealed a radiant collagen layer covered with nerves and macrophages at 0 to 20 μm. Below at 20 to 25 μm we visualized a thick muscle layer containing elastic fibers and macrophages. Findings were also represented in 3-dimensional reconstructions, providing information on structure localization, orientation and interconnection. CONCLUSIONS Two-photon laser scanning microscopy imaging using autofluorescence of the murine bladder is a promising technique to provide new insight into structures and morphology. It opens avenues to identify structural changes in bladder pathology.
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Affiliation(s)
- Anna Schueth
- Department of Urology, Maastricht University Medical Center, Maastricht University, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
| | - Marc A M J van Zandvoort
- Department of Genetics and Cell Biology-Molecular Cell Biology, School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands; Institute for Molecular Cardiovascular Research, Rheinisch-Westfälische Technische Hochschule Aachen University of Aachen, Aachen, Germany
| | - Wim A Buurman
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Gommert A van Koeveringe
- Department of Urology, Maastricht University Medical Center, Maastricht University, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
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The Histochem Cell Biol conspectus: the year 2013 in review. Histochem Cell Biol 2014; 141:337-63. [PMID: 24610091 PMCID: PMC7087837 DOI: 10.1007/s00418-014-1207-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2014] [Indexed: 11/29/2022]
Abstract
Herein, we provide a brief synopsis of all manuscripts published in Histochem Cell Biol in the year 2013. For ease of reference, we have divided the manuscripts into the following categories: Advances in Methodologies; Molecules in Health and Disease; Organelles, Subcellular Structures and Compartments; Golgi Apparatus; Intermediate Filaments and Cytoskeleton; Connective Tissue and Extracellular Matrix; Autophagy; Stem Cells; Musculoskeletal System; Respiratory and Cardiovascular Systems; Gastrointestinal Tract; Central Nervous System; Peripheral Nervous System; Excretory Glands; Kidney and Urinary Bladder; and Male and Female Reproductive Systems. We hope that the readership will find this annual journal synopsis of value and serve as a quick, categorized reference guide for “state-of-the-art” manuscripts in the areas of histochemistry, immunohistochemistry, and cell biology.
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Shimizu Y, Mochizuki S, Mitsui R, Hashitani H. Neurohumoral regulation of spontaneous constrictions in suburothelial venules of the rat urinary bladder. Vascul Pharmacol 2014; 60:84-94. [PMID: 24418022 DOI: 10.1016/j.vph.2014.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/30/2013] [Accepted: 01/03/2014] [Indexed: 10/25/2022]
Abstract
Venules of the bladder suburothelium develop spontaneous phasic constrictions that may play a critical role in maintaining venular drainage of tissue metabolites. We aimed to investigate neurohumoral regulation of the spontaneous venular constrictions (SVCs). Changes in venular diameter of the rat bladder suburothelium were monitored using a video tracking system, whilst the effects of electrical field stimulation (EFS) and bath-applied bioactive substances were investigated. The innervation of the suburothelial microvasculature was examined by immunohistochemistry. EFS (10Hz for 30s) induced an increase in the frequency of SVCs that was prevented by phentolamine (1μM). In phentolamine-pretreated venules, EFS suppressed SVCs with a venular dilatation in a manner attenuated by propranolol (1μM) or l-nitro arginine (LNA, 10μM). BRL37344 (1μM), a β3 adrenoceptor agonist, dilated venules and reduced the frequency of SVCs in an LNA-sensitive manner. ACh (1-10μM) increased the frequency of SVCs. ATP (1μM) transiently constricted venules and then caused LNA-sensitive cessation of SVCs associated with a dilatation. Substance P (100nM) caused a venular constriction, whilst calcitonin gene related peptide (CGRP, 100nM) caused a dilatation of venules and suppression of SVCs that were not inhibited by LNA. Immunohistochemical staining demonstrated sympathetic as well as substance P- and CGRP-containing nerves running along the venules. Spontaneous constrictions of suburothelial venules are accelerated by sympathetic α-adrenergic stimulation, but suppressed upon β-adrenergic stimulation. In addition, suburothelial venular constrictions appear to be modulated by several bioactive substances that could be released from urothelium or suburothelial sensory nerves.
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Affiliation(s)
- Yuki Shimizu
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Satoshi Mochizuki
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
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