1
|
Sharkey KA, Greenwood-Van Meerveld B. Dr. Gary M. Mawe: A tribute to a scholar, mentor, and friend. Neurogastroenterol Motil 2024; 36:e14807. [PMID: 38654527 DOI: 10.1111/nmo.14807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 04/26/2024]
Affiliation(s)
- Keith A Sharkey
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | | |
Collapse
|
2
|
Liu Y, Fan Y, Wu S. Developments in research on interstitial Cajal-like cells in the biliary tract. Expert Rev Gastroenterol Hepatol 2021; 15:159-164. [PMID: 32933347 DOI: 10.1080/17474124.2021.1823214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Interstitial cells of Cajal (ICCs) are a special type of interstitial cells located in the gastrointestinal tract muscles. They are closely related to smooth muscle cells and neurons, participate in gastrointestinal motility and nerve signal transmission, and are pacemaker cells for gastrointestinal electrical activity. Research interest in ICCs has continuously grown since they were first discovered in 1893. Later, researchers discovered that they are also present in other organs, including the biliary tract, urethra, bladder, etc.; these cells were named interstitial Cajal-like cells (ICLCs), and attempts have been made to explain their relationships with certain diseases. AREAS COVERED This review paper summarizes the morphology, identification, classification, function, and distribution of ICLCs in the biliary tract and their relationship to biliary tract diseases. EXPERT OPINION Based on the function and distribution of ICLCs in the biliary tract system, ICLCs will provide a more reliable theoretical basis for the mechanisms of pathogenesis of and treatments for biliary tract diseases.
Collapse
Affiliation(s)
- Yingyu Liu
- Department of General Surgery, Shengjing Hospital of China Medical University , Shenyang, China
| | - Ying Fan
- Department of General Surgery, Shengjing Hospital of China Medical University , Shenyang, China
| | - Shuodong Wu
- Department of General Surgery, Shengjing Hospital of China Medical University , Shenyang, China
| |
Collapse
|
3
|
Balemba OB, Stark TD, Lösch S, Patterson S, McMillan JS, Mawe GM, Hofmann T. (2R,3S,2'' R,3''R)-manniflavanone, a new gastrointestinal smooth muscle L-type calcium channel inhibitor, which underlies the spasmolytic properties of Garcinia buchananii stem bark extract. J Smooth Muscle Res 2016; 50:48-65. [PMID: 26081368 PMCID: PMC4826780 DOI: 10.1540/jsmr.50.48] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Garcinia buchananii Baker stem bark extract (GBB) is a traditional
medication of diarrhea and dysentery in sub-Saharan Africa. It is believed that GBB causes
gastrointestinal smooth muscle relaxation. The aim of this study was to determine whether
GBB has spasmolytic actions and identify compounds underlying these actions. Calcium
(Ca2+) imaging was used to analyze the effect of GBB on Ca2+
flashes and Ca2+ waves in guinea pig gallbladder and distal colon smooth
muscle. Intracellular microelectrode recording was used to determine the effect of GBB,
six fractions of GBB, M1–5 and M7, and
(2R,3S,2”R,3”R)-manniflavanone,
a compound isolated from M3 on action potentials in gallbladder smooth muscle. The
technique was also used to analyze the effect of GBB, M3, and
(2R,3S,2”R,3”R)-manniflavanone
on action potentials in the circular muscle of mouse and guinea pig distal colons, and the
effect of GBB and
(2R,3S,2”R,3”R)-manniflavanone
on slow waves in porcine ileum. GBB inhibited Ca2+ flashes and Ca2+
waves. GBB, M3 and
(2R,3S,2”R,3”R)-manniflavanone
inhibited action potentials. L-type Ca2+ channel activator Bay K 8644 increased
the discharge of action potentials in mouse colon but did not trigger or increase action
potentials in the presence of GBB and
(2R,3S,2”R,3”R)-manniflavanone.
GBB and
(2R,3S,2”R,3”R)-manniflavanone
inhibited action potentials in the presence of Bay K 8644. GBB and
(2R,3S,2”R,3”R)-manniflavanone
reduced the amplitude but did not alter the frequency of slow waves in the porcine ileum.
In conclusion, GBB and
(2R,3S,2”R,3”R)-manniflavanone
relax smooth muscle by inhibiting L-type Ca2+ channels, thus have potential for
use as therapies of gastrointestinal smooth muscle spasms, and arrhythmias.
Collapse
Affiliation(s)
- Onesmo B Balemba
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States
| | | | | | | | | | | | | |
Collapse
|
4
|
Woods SE, Leonard MR, Hayden JA, Brophy MB, Bernert KR, Lavoie B, Muthupalani S, Whary MT, Mawe GM, Nolan EM, Carey MC, Fox JG. Impaired cholecystokinin-induced gallbladder emptying incriminated in spontaneous "black" pigment gallstone formation in germfree Swiss Webster mice. Am J Physiol Gastrointest Liver Physiol 2015; 308:G335-49. [PMID: 25477375 PMCID: PMC4329474 DOI: 10.1152/ajpgi.00314.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
"Black" pigment gallstones form in sterile gallbladder bile in the presence of excess bilirubin conjugates ("hyperbilirubinbilia") from ineffective erythropoiesis, hemolysis, or induced enterohepatic cycling (EHC) of unconjugated bilirubin. Impaired gallbladder motility is a less well-studied risk factor. We evaluated the spontaneous occurrence of gallstones in adult germfree (GF) and conventionally housed specific pathogen-free (SPF) Swiss Webster (SW) mice. GF SW mice were more likely to have gallstones than SPF SW mice, with 75% and 23% prevalence, respectively. In GF SW mice, gallstones were observed predominately in heavier, older females. Gallbladders of GF SW mice were markedly enlarged, contained sterile black gallstones composed of calcium bilirubinate and <1% cholesterol, and had low-grade inflammation, edema, and epithelial hyperplasia. Hemograms were normal, but serum cholesterol was elevated in GF compared with SPF SW mice, and serum glucose levels were positively related to increasing age. Aged GF and SPF SW mice had deficits in gallbladder smooth muscle activity. In response to cholecystokinin (CCK), gallbladders of fasted GF SW mice showed impaired emptying (females: 29%; males: 1% emptying), whereas SPF SW females and males emptied 89% and 53% of volume, respectively. Bilirubin secretion rates of GF SW mice were not greater than SPF SW mice, repudiating an induced EHC. Gallstones likely developed in GF SW mice because of gallbladder hypomotility, enabled by features of GF physiology, including decreased intestinal CCK concentration and delayed intestinal transit, as well as an apparent genetic predisposition of the SW stock. GF SW mice may provide a valuable model to study gallbladder stasis as a cause of black pigment gallstones.
Collapse
Affiliation(s)
- Stephanie E. Woods
- 1Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts;
| | - Monika R. Leonard
- 2Division of Gastroenterology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts;
| | - Joshua A. Hayden
- 3Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Megan Brunjes Brophy
- 3Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Kara R. Bernert
- 2Division of Gastroenterology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts;
| | - Brigitte Lavoie
- 4Department of Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Sureshkumar Muthupalani
- 1Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts;
| | - Mark T. Whary
- 1Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts;
| | - Gary M. Mawe
- 4Department of Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Elizabeth M. Nolan
- 3Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Martin C. Carey
- 2Division of Gastroenterology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts;
| | - James G. Fox
- 1Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts;
| |
Collapse
|
5
|
Lavoie B, Nausch B, Zane E, Leonard M, Balemba O, Bartoo A, Wilcox R, Nelson M, Carey M, Mawe G. Disruption of gallbladder smooth muscle function is an early feature in the development of cholesterol gallstone disease. Neurogastroenterol Motil 2012; 24:e313-24. [PMID: 22621672 PMCID: PMC3378777 DOI: 10.1111/j.1365-2982.2012.01935.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
UNLABELLED BACKGROUND; Decreased gallbladder smooth muscle (GBSM) contractility is a hallmark of cholesterol gallstone disease, but the interrelationship between lithogenicity, biliary stasis, and inflammation are poorly understood. We studied a mouse model of gallstone disease to evaluate the development of GBSM dysfunction relative to changes in bile composition and the onset of sterile cholecystitis. METHODS BALB/cJ mice were fed a lithogenic diet for up to 8 weeks, and tension generated by gallbladder muscle strips was measured. Smooth muscle Ca(2+) transients were imaged in intact gallbladder. KEY RESULTS Lipid composition of bile was altered lithogenically as early as 1 week, with increased hydrophobicity and cholesterol saturation indexes; however, inflammation was not detectable until the fourth week. Agonist-induced contractility was reduced from weeks 2 through 8. GBSM normally exhibits rhythmic synchronized Ca(2+) flashes, and their frequency is increased by carbachol (3 μm). After 1 week, lithogenic diet-fed mice exhibited disrupted Ca(2+) flash activity, manifesting as clustered flashes, asynchronous flashes, or prolonged quiescent periods. These changes could lead to a depletion of intracellular Ca(2+) stores, which are required for agonist-induced contraction, and diminished basal tone of the organ. Responsiveness of Ca(2+) transients to carbachol was reduced in mice on the lithogenic diet, particularly after 4-8 weeks, concomitant with appearance of mucosal inflammatory changes. CONCLUSIONS & INFERENCES These observations demonstrate that GBSM dysfunction is an early event in the progression of cholesterol gallstone disease and that it precedes mucosal inflammation.
Collapse
Affiliation(s)
- B. Lavoie
- Department of Anatomy and Neurobiology, University of Vermont School of Medicine, Burlington, VT
| | - B. Nausch
- Department of Anatomy and Neurobiology, University of Vermont School of Medicine, Burlington, VT
| | - E.A. Zane
- Department of Medicine, Harvard Medical School, Gastroenterology Division, Brigham and Women's Hospital, Boston, MA
| | - M.R. Leonard
- Department of Medicine, Harvard Medical School, Gastroenterology Division, Brigham and Women's Hospital, Boston, MA
| | - O.B. Balemba
- Department of Anatomy and Neurobiology, University of Vermont School of Medicine, Burlington, VT
| | - A.C. Bartoo
- Department of Anatomy and Neurobiology, University of Vermont School of Medicine, Burlington, VT
| | - R. Wilcox
- Department of Pathology, University of Vermont School of Medicine, Burlington, VT
| | - M.T. Nelson
- Department of Pharmacology, University of Vermont School of Medicine, Burlington, VT
| | - M.C. Carey
- Department of Medicine, Harvard Medical School, Gastroenterology Division, Brigham and Women's Hospital, Boston, MA
| | - G.M. Mawe
- Department of Anatomy and Neurobiology, University of Vermont School of Medicine, Burlington, VT
- Department of Pharmacology, University of Vermont School of Medicine, Burlington, VT
| |
Collapse
|
6
|
McCarron JG, Chalmers S, Olson ML, Girkin JM. Subplasma membrane Ca2+ signals. IUBMB Life 2012; 64:573-85. [PMID: 22653514 PMCID: PMC3638344 DOI: 10.1002/iub.1032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 12/03/2022]
Abstract
Ca2+ may selectively activate various processes in part by the cell's ability to localize changes in the concentration of the ion to specific subcellular sites. Interestingly, these Ca2+ signals begin most often at the plasma membrane space so that understanding subplasma membrane signals is central to an appreciation of local signaling. Several experimental procedures have been developed to study Ca2+ signals near the plasma membrane, but probably the most prevalent involve the use of fluorescent Ca2+ indicators and fall into two general approaches. In the first, the Ca2+ indicators themselves are specifically targeted to the subplasma membrane space to measure Ca2+ only there. Alternatively, the indicators are allowed to be dispersed throughout the cytoplasm, but the fluorescence emanating from the Ca2+ signals at the subplasma membrane space is selectively measured using high resolution imaging procedures. Although the targeted indicators offer an immediate appeal because of selectivity and ease of use, their limited dynamic range and slow response to changes in Ca2+ are a shortcoming. Use of targeted indicators is also largely restricted to cultured cells. High resolution imaging applied with rapidly responding small molecule Ca2+ indicators can be used in all cells and offers significant improvements in dynamic range and speed of response of the indicator. The approach is technically difficult, however, and realistic calibration of signals is not possible. In this review, a brief overview of local subplasma membrane Ca2+ signals and methods for their measurement is provided. © 2012 IUBMB IUBMB Life, 64(7): 573–585, 2012
Collapse
Affiliation(s)
- John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
| | | | | | | |
Collapse
|
7
|
McCarron JG, Olson ML, Chalmers S. Mitochondrial regulation of cytosolic Ca²⁺ signals in smooth muscle. Pflugers Arch 2012; 464:51-62. [PMID: 22555917 DOI: 10.1007/s00424-012-1108-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/11/2012] [Indexed: 11/25/2022]
Abstract
The cytosolic Ca²⁺ concentration ([Ca²⁺]c) controls virtually every activity of smooth muscle, including contraction, migration, transcription, division and apoptosis. These processes may be activated by large (>10 μM) amplitude [Ca²⁺]c increases, which occur in small restricted regions of the cell or by smaller (<1 μM) amplitude changes throughout the bulk cytoplasm. Mitochondria contribute to the regulation of these signals by taking up Ca²⁺. However, mitochondria's reported low affinity for Ca²⁺ is thought to require the organelle to be positioned close to ion channels and within a microdomain of high [Ca²⁺]. In cultured smooth muscle, mitochondria are highly dynamic structures but in native smooth muscle mitochondria are immobile, apparently strategically positioned organelles that regulate the upstroke and amplitude of IP₃-evoked Ca²⁺ signals and IP₃ receptor (IP₃R) cluster activity. These observations suggest mitochondria are positioned within the high [Ca²⁺] microdomain arising from an IP₃R cluster to exert significant local control of channel activity. On the other hand, neither the upstroke nor amplitude of voltage-dependent Ca²⁺ entry is modulated by mitochondria; rather, it is the declining phase of the transient that is regulated by the organelle. Control of the declining phase of the transient requires a high mitochondrial affinity for Ca²⁺ to enable uptake to occur over the normal physiological Ca²⁺ range (<1 μM). Thus, in smooth muscle, mitochondria regulate Ca²⁺ signals exerting effects over a large range of [Ca²⁺] (∼200 nM to at least tens of micromolar) to provide a wide dynamic range in the control of Ca²⁺ signals.
Collapse
Affiliation(s)
- John G McCarron
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, John Arbuthnott Building, 161 Cathedral Street, Glasgow, G4 0NR, UK.
| | | | | |
Collapse
|
8
|
Narayanan D, Adebiyi A, Jaggar JH. Inositol trisphosphate receptors in smooth muscle cells. Am J Physiol Heart Circ Physiol 2012; 302:H2190-210. [PMID: 22447942 DOI: 10.1152/ajpheart.01146.2011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) are a family of tetrameric intracellular calcium (Ca(2+)) release channels that are located on the sarcoplasmic reticulum (SR) membrane of virtually all mammalian cell types, including smooth muscle cells (SMC). Here, we have reviewed literature investigating IP(3)R expression, cellular localization, tissue distribution, activity regulation, communication with ion channels and organelles, generation of Ca(2+) signals, modulation of physiological functions, and alterations in pathologies in SMCs. Three IP(3)R isoforms have been identified, with relative expression and cellular localization of each contributing to signaling differences in diverse SMC types. Several endogenous ligands, kinases, proteins, and other modulators control SMC IP(3)R channel activity. SMC IP(3)Rs communicate with nearby ryanodine-sensitive Ca(2+) channels and mitochondria to influence SR Ca(2+) release and reactive oxygen species generation. IP(3)R-mediated Ca(2+) release can stimulate plasma membrane-localized channels, including transient receptor potential (TRP) channels and store-operated Ca(2+) channels. SMC IP(3)Rs also signal to other proteins via SR Ca(2+) release-independent mechanisms through physical coupling to TRP channels and local communication with large-conductance Ca(2+)-activated potassium channels. IP(3)R-mediated Ca(2+) release generates a wide variety of intracellular Ca(2+) signals, which vary with respect to frequency, amplitude, spatial, and temporal properties. IP(3)R signaling controls multiple SMC functions, including contraction, gene expression, migration, and proliferation. IP(3)R expression and cellular signaling are altered in several SMC diseases, notably asthma, atherosclerosis, diabetes, and hypertension. In summary, IP(3)R-mediated pathways control diverse SMC physiological functions, with pathological alterations in IP(3)R signaling contributing to disease.
Collapse
Affiliation(s)
- Damodaran Narayanan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, 38163, USA
| | | | | |
Collapse
|
9
|
Tumelty J, Hinds K, Bankhead P, McGeown NJ, Scholfield CN, Curtis TM, McGeown JG. Endothelin 1 stimulates Ca2+-sparks and oscillations in retinal arteriolar myocytes via IP3R and RyR-dependent Ca2+ release. Invest Ophthalmol Vis Sci 2011; 52:3874-9. [PMID: 21372022 DOI: 10.1167/iovs.10-6029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
PURPOSE To investigate endothelin 1 (Et1)-dependent Ca(2+)-signaling at the cellular and subcellular levels in retinal arteriolar myocytes. METHODS Et1 responses were imaged from Fluo-4-loaded smooth muscle in isolated segments of rat retinal arteriole using confocal laser microscopy. RESULTS Basal [Ca(2+)](i), subcellular Ca(2+)-sparks, and cellular Ca(2+)-oscillations were all increased during exposure to Et1 (10 nM). Ca(2+)-spark frequency was also increased by 90% by 10 nM Et1. The increase in oscillation frequency was concentration dependent and was inhibited by the EtA receptor (Et(A)R) blocker BQ123 but not by the EtB receptor antagonist BQ788. Stimulation of Ca(2+)-oscillations by Et1 was inhibited by a phospholipase C blocker (U73122; 10 μM), two inhibitors of inositol 1,4,5-trisphosphate receptors (IP(3)Rs), xestospongin C (10 μM), 2-aminoethoxydiphenyl borate (100 μM), and tetracaine (100 μM), a blocker of ryanodine receptors (RyRs). CONCLUSIONS Et1 stimulates Ca(2+)-sparks and oscillations through Et(A)Rs. The underlying mechanism involves the activation of phospholipase C and both IP(3)Rs and RyRs, suggesting crosstalk between these Ca(2+)-release channels. These findings suggest that phasic Ca(2+)-oscillations play an important role in the smooth muscle response to Et1 within the retinal microvasculature and support an excitatory, proconstrictor role for Ca(2+)-sparks in these vessels.
Collapse
Affiliation(s)
- James Tumelty
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Sciences, The Royal Victoria Hospital, Belfast, Northern Ireland
| | | | | | | | | | | | | |
Collapse
|
10
|
McCarron JG, Chalmers S, MacMillan D, Olson ML. Agonist-evoked Ca(2+) wave progression requires Ca(2+) and IP(3). J Cell Physiol 2010; 224:334-44. [PMID: 20432430 PMCID: PMC3947531 DOI: 10.1002/jcp.22103] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Smooth muscle responds to IP(3)-generating agonists by producing Ca(2+) waves. Here, the mechanism of wave progression has been investigated in voltage-clamped single smooth muscle cells using localized photolysis of caged IP(3) and the caged Ca(2+) buffer diazo-2. Waves, evoked by the IP(3)-generating agonist carbachol (CCh), initiated as a uniform rise in cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) over a single though substantial length (approximately 30 microm) of the cell. During regenerative propagation, the wave-front was about 1/3 the length (approximately 9 microm) of the initiation site. The wave-front progressed at a relatively constant velocity although amplitude varied through the cell; differences in sensitivity to IP(3) may explain the amplitude changes. Ca(2+) was required for IP(3)-mediated wave progression to occur. Increasing the Ca(2+) buffer capacity in a small (2 microm) region immediately in front of a CCh-evoked Ca(2+) wave halted progression at the site. However, the wave front does not progress by Ca(2+)-dependent positive feedback alone. In support, colliding [Ca(2+)](c) increases from locally released IP(3) did not annihilate but approximately doubled in amplitude. This result suggests that local IP(3)-evoked [Ca(2+)](c) increases diffused passively. Failure of local increases in IP(3) to evoke waves appears to arise from the restricted nature of the IP(3) increase. When IP(3) was elevated throughout the cell, a localized increase in Ca(2+) now propagated as a wave. Together, these results suggest that waves initiate over a surprisingly large length of the cell and that both IP(3) and Ca(2+) are required for active propagation of the wave front to occur.
Collapse
Affiliation(s)
- John G McCarron
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, John Arbuthnott Building, Glasgow, UK.
| | | | | | | |
Collapse
|
11
|
Lavoie B, Balemba OB, Godfrey C, Watson CA, Vassileva G, Corvera CU, Nelson MT, Mawe GM. Hydrophobic bile salts inhibit gallbladder smooth muscle function via stimulation of GPBAR1 receptors and activation of KATP channels. J Physiol 2010; 588:3295-305. [PMID: 20624794 DOI: 10.1113/jphysiol.2010.192146] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hydrophobic bile salts are thought to contribute to the disruption of gallbladder smooth muscle (GBSM) function that occurs in gallstone disease, but their mechanism of action is unknown. The current study was undertaken to determine how hydrophobic bile salts interact with GBSM, and how they reduce GBSM activity. The effect of hydrophobic bile salts on the activity of GBSM was measured by intracellular recording and calcium imaging using wholemount preparations from guinea pig and mouse gallbladder. RT-PCR and immunohistochemistry were used to evaluate expression of the G protein-coupled bile acid receptor, GPBAR1. Application of tauro-chenodeoxycholate (CDC, 50-100 microm) to in situ GBSM rapidly reduced spontaneous Ca(2+) flashes and action potentials, and caused a membrane hyperpolarization. Immunoreactivity and transcript for GPBAR1 were detected in gallbladder muscularis. The GPBAR1 agonist, tauro-lithocholic acid (LCA, 10 microm) mimicked the effect of CDC on GBSM. The actions of LCA were blocked by the protein kinase A (PKA) inhibitor, KT5720 (0.5-1.0 microm) and the K(ATP) channel blocker, glibenclamide (10 microm). Furthermore, LCA failed to disrupt GBSM activity in Gpbar1(/) mice. The findings of this study indicate that hydrophobic bile salts activate GPBAR1 on GBSM, and this leads to activation of the cyclic AMP-PKA pathway, and ultimately the opening of K(ATP) channels, thus hyperpolarizing the membrane and decreasing GBSM activity. This inhibitory effect of hydrophobic bile salt activation of GPBAR1 could be a contributing factor in the manifestation of gallstone disease.
Collapse
Affiliation(s)
- Brigitte Lavoie
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington VT 05405, USA
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Wu ZX, Yu BP, Xia H, Xu L. Emodin increases Ca2+ influx through L-type Ca2+ channel in guinea pig gallbladder smooth muscle. Eur J Pharmacol 2008; 595:95-9. [DOI: 10.1016/j.ejphar.2008.07.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 07/21/2008] [Accepted: 07/24/2008] [Indexed: 01/31/2023]
|
13
|
Bartoo AC, Nelson MT, Mawe GM. ATP induces guinea pig gallbladder smooth muscle excitability via the P2Y4 receptor and COX-1 activity. Am J Physiol Gastrointest Liver Physiol 2008; 294:G1362-8. [PMID: 18436624 PMCID: PMC2921626 DOI: 10.1152/ajpgi.00043.2008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The purpose of this study was to elucidate the mechanisms by which ATP increases guinea pig gallbladder smooth muscle (GBSM) excitability. We evaluated changes in membrane potential and action potential (AP) frequency in GBSM by use of intracellular recording. Application of ATP (100 microM) caused membrane depolarization and a significant increase in AP frequency that were not sensitive to block by tetrodotoxin (0.5 microM). The nonselective P2 antagonist, suramin (100 microM), blocked the excitatory response, resulting in decreased AP frequency in the presence of ATP. The excitatory response to ATP was not altered by pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid (30 microM), a nonselective P2X antagonist. UTP also caused membrane depolarization and increased AP frequency, with a similar dose-response relationship as ATP. RT-PCR demonstrated that the P2Y(4), but not P2Y(2), receptor subtype is expressed in guinea pig gallbladder muscularis. ATP induced excitation was blocked by indomethacin (10 microM) and the cyclooxygenase (COX)-1 inhibitor SC-560 (300 nM), but not the COX-2 inhibitor nimesulide (500 nM). These data suggest that ATP stimulates P2Y(4) receptors within the gallbladder muscularis and, in turn, stimulate prostanoid production via COX-1 leading to increased excitability of GBSM.
Collapse
Affiliation(s)
- Aaron C. Bartoo
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, Burlington, Vermont
| | - Mark T. Nelson
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
| | - Gary M. Mawe
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, Burlington, Vermont,Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
| |
Collapse
|
14
|
Balemba OB, Bartoo AC, Nelson MT, Mawe GM. Role of mitochondria in spontaneous rhythmic activity and intracellular calcium waves in the guinea pig gallbladder smooth muscle. Am J Physiol Gastrointest Liver Physiol 2008; 294:G467-76. [PMID: 18048480 DOI: 10.1152/ajpgi.00415.2007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mitochondrial Ca(2+) handling has been implicated in spontaneous rhythmic activity in smooth muscle and interstitial cells of Cajal. In this investigation we evaluated the effect of mitochondrial inhibitors on spontaneous action potentials (APs), Ca(2+) flashes, and Ca(2+) waves in gallbladder smooth muscle (GBSM). Disruption of the mitochondrial membrane potential with carbonyl cyanide 3-chlorophenylhydrazone, carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone, rotenone, and antimycin A significantly reduced or eliminated APs, Ca(2+) flashes, and Ca(2+) waves in GBSM. Blockade of ATP production with oligomycin did not alter APs or Ca(2+) flashes but significantly reduced Ca(2+) wave frequency. Inhibition of mitochondrial Ca(2+) uptake and Ca(2+) release with Ru360 and CGP-37157, respectively, reduced the frequency of Ca(2+) flashes and Ca(2+) waves in GBSM. Similar to oligomycin, cyclosporin A did not alter AP and Ca(2+) flash frequency but significantly reduced Ca(2+) wave activity. These data suggest that mitochondrial Ca(2+) handling is necessary for the generation of spontaneous electrical activity and may therefore play an important role in gallbladder tone and motility.
Collapse
Affiliation(s)
- Onesmo B Balemba
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, 89 Beaumont Ave., D406 Given Bldg., Burlington, VT 05405, USA
| | | | | | | |
Collapse
|
15
|
Lavoie B, Balemba OB, Nelson MT, Ward SM, Mawe GM. Morphological and physiological evidence for interstitial cell of Cajal-like cells in the guinea pig gallbladder. J Physiol 2007; 579:487-501. [PMID: 17204499 PMCID: PMC2075389 DOI: 10.1113/jphysiol.2006.122861] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Gallbladder smooth muscle (GBSM) exhibits spontaneous rhythmic electrical activity, but the origin and propagation of this activity are not understood. We used morphological and physiological approaches to determine whether interstitial cells of Cajal (ICC) are present in the guinea pig extrahepatic biliary tree. Light microscopic studies involving Kit tyrosine kinase immunohistochemistry and laser confocal imaging of Ca(2+) transients revealed ICC-like cells in the gallbladder. One type of ICC-like cell had elongated cell bodies with one or two primary processes and was observed mainly along GBSM bundles and nerve fibres. The other type comprised multipolar cells that were located at the origin and intersection of muscle bundles. Electron microscopy revealed ICC-like cells that were rich in mitochondria, caveolae and smooth endoplasmic reticulum and formed close appositions between themselves and with GBSM cells. Rhythmic Ca(2+) flashes, which represent Ca(2+) influx during action potentials, were synchronized in any given GBSM bundle and associated ICC-like cells. Gap junction uncouplers (1-octanol, carbenoxolone, 18beta-glycyrrhetinic acid and connexin mimetic peptide) eliminated or greatly reduced Ca(2+) flashes in GBSM, but they persisted in ICC-like cells, whereas the Kit tyrosine kinase inhibitor, imanitib mesylate, eliminated or reduced action potentials and Ca(2+) flashes in both cell types, as well as associated tissue contractions. This study provides morphological and physiological evidence for the existence of ICC-like cells in the gallbladder and presents data supporting electrical coupling between ICC-like and GBSM cells. The results support a role for ICC-like cells in the generation and propagation of spontaneous rhythmicity, and hence, the excitability of gallbladder.
Collapse
Affiliation(s)
- Brigitte Lavoie
- Department of Anatomy, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | | | | | | | | |
Collapse
|