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Hibberd TJ, Ramsay S, Spencer-Merris P, Dinning PG, Zagorodnyuk VP, Spencer NJ. Circadian rhythms in colonic function. Front Physiol 2023; 14:1239278. [PMID: 37711458 PMCID: PMC10498548 DOI: 10.3389/fphys.2023.1239278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023] Open
Abstract
A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.
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Affiliation(s)
- Timothy J. Hibberd
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Stewart Ramsay
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | | | - Phil G. Dinning
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
- Colorectal Surgical Unit, Division of Surgery, Flinders Medical Centre, Adelaide, SA, Australia
| | | | - Nick J. Spencer
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
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Elfers K, Schäuffele S, Hoppe S, Michel K, Zeller F, Demir IE, Schemann M, Mazzuoli-Weber G. Distension evoked mucosal secretion in human and porcine colon in vitro. PLoS One 2023; 18:e0282732. [PMID: 37053302 PMCID: PMC10101454 DOI: 10.1371/journal.pone.0282732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 02/20/2023] [Indexed: 04/15/2023] Open
Abstract
It was suggested that intestinal mucosal secretion is enhanced during muscle relaxation and contraction. Mechanisms of mechanically induced secretion have been studied in rodent species. We used voltage clamp Ussing technique to investigate, in human and porcine colonic tissue, secretion evoked by serosal (Pser) or mucosal (Pmuc) pressure application (2-60 mmHg) to induce distension into the mucosal or serosal compartment, respectively. In both species, Pser or Pmuc caused secretion due to Cl- and, in human colon, also HCO3- fluxes. In the human colon, responses were larger in proximal than distal regions. In porcine colon, Pmuc evoked larger responses than Pser whereas the opposite was the case in human colon. In both species, piroxicam revealed a strong prostaglandin (PG) dependent component. Pser and Pmuc induced secretion was tetrodotoxin (TTX) sensitive in porcine colon. In human colon, a TTX sensitive component was only revealed after piroxicam. However, synaptic blockade by ω-conotoxin GVIA reduced the response to mechanical stimuli. Secretion was induced by tensile rather than compressive forces as preventing distension by a filter inhibited the secretion. In conclusion, in both species, distension induced secretion was predominantly mediated by PGs and a rather small nerve dependent response involving mechanosensitive somata and synapses.
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Affiliation(s)
- Kristin Elfers
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Susanne Hoppe
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Klaus Michel
- Chair of Human Biology, Technical University of Munich, Freising, Germany
| | | | - Ihsan Ekin Demir
- University Hospital Rechts der Isar, Technical University of Munich, München, Germany
| | - Michael Schemann
- Chair of Human Biology, Technical University of Munich, Freising, Germany
| | - Gemma Mazzuoli-Weber
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
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Smolilo DJ, Hibberd TJ, Costa M, Dinning PG, Keightley LJ, De Fontgalland D, Wattchow D, Spencer NJ. Stimulation of extrinsic sympathetic nerves differentially affects neurogenic motor activity in guinea pig distal colon. Physiol Rep 2023; 11:e15567. [PMID: 36636780 PMCID: PMC9837477 DOI: 10.14814/phy2.15567] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/25/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023] Open
Abstract
The speed of pellet propulsion through the isolated guinea pig distal colon in vitro significantly exceeds in vivo measurements, suggesting a role for inhibitory mechanisms from sources outside the gut. The aim of this study was to investigate the effects of sympathetic nerve stimulation on three different neurogenic motor behaviors of the distal colon: transient neural events (TNEs), colonic motor complexes (CMCs), and pellet propulsion. To do this, segments of guinea pig distal colon with intact connections to the inferior mesenteric ganglion (IMG) were set up in organ baths allowing for simultaneous extracellular suction electrode recordings from smooth muscle, video recordings for diameter mapping, and intraluminal manometry. Electrical stimulation (1-20 Hz) of colonic nerves surrounding the inferior mesenteric artery caused a statistically significant, frequency-dependent inhibition of TNEs, as well as single pellet propulsion, from frequencies of 5 Hz and greater. Significant inhibition of CMCs required stimulation frequencies of 10 Hz and greater. Phentolamine (3.6 μM) abolished effects of colonic nerve stimulation, consistent with a sympathetic noradrenergic mechanism. Sympathetic inhibition was constrained to regions with intact extrinsic nerve pathways, allowing normal motor behaviors to continue without modulation in adjacent extrinsically denervated regions of the same colonic segments. The results demonstrate differential sensitivities to sympathetic input among distinct neurogenic motor behaviors of the colon. Together with findings indicating CMCs activate colo-colonic sympathetic reflexes through the IMG, these results raise the possibility that CMCs may paradoxically facilitate suppression of pellet movement in vivo, through peripheral sympathetic reflex circuits.
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Affiliation(s)
- David J. Smolilo
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
| | - Timothy J. Hibberd
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
| | - Marcello Costa
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
| | - Phil G. Dinning
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
- Department of SurgeryFlinders Medical CentreBedford ParkSouth AustraliaAustralia
- Department of GastroenterologyFlinders Medical CentreBedford ParkSouth AustraliaAustralia
| | - Lauren J. Keightley
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
| | - Dayan De Fontgalland
- Department of SurgeryFlinders Medical CentreBedford ParkSouth AustraliaAustralia
- Department of GastroenterologyFlinders Medical CentreBedford ParkSouth AustraliaAustralia
| | - David A. Wattchow
- Department of SurgeryFlinders Medical CentreBedford ParkSouth AustraliaAustralia
- Department of GastroenterologyFlinders Medical CentreBedford ParkSouth AustraliaAustralia
| | - Nick J. Spencer
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
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Hibberd TJ, Costa M, Smolilo DJ, Keightley LJ, Brookes SJ, Dinning PG, Spencer NJ. Mechanisms underlying initiation of propulsion in guinea pig distal colon. Am J Physiol Gastrointest Liver Physiol 2022; 323:G71-G87. [PMID: 35502864 DOI: 10.1152/ajpgi.00055.2022] [Citation(s) in RCA: 2] [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
Colonic motor complexes (CMCs) are a major neurogenic activity in guineapig distal colon. The identity of the enteric neurons that initiate this activity is not established. Specialized intrinsic primary afferent neurons (IPANs) are a major candidate. We aimed to test this hypothesis. To do this, segments of guineapig distal colon were suspended vertically in heated organ baths and propulsive forces acting on a pellet inside the lumen were recorded by isometric force transducer while pharmacological agents were applied to affect IPAN function. In the absence of drugs, CMCs acted periodically on the pellet, generating peak propulsive forces of 12.7 ± 5 g at 0.56 ± 0.22 cpm, lasting 49 ± 17 s (215 preparations; n = 60). Most but not all CMCs were abolished by nicotinic receptor blockade to inhibit fast excitatory synaptic transmission (50/62 preparations; n = 25). Remarkably, CMCs inhibited by hexamethonium were restored by a pharmacological strategy that aimed to enhance IPAN excitability. Thus, CMCs were restored by increased smooth muscle tension (using BAY K8644, bethanechol or carbachol) and by IPAN excitation using phorbol dibutyrate; NK3 receptor agonist, senktide; and partially by αCGRP. The IPAN inhibitor, 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazole-2-one (DCEBIO), decreased CMC frequency. CGRP, but not NK3-receptor antagonists, decreased CMC frequency in naive preparations. Finally, CMCs were blocked by tetrodotoxin, and this was not reversed by any drugs listed above. These results support a major role for IPANs that does not require fast synaptic transmission, in the periodic initiation of neurogenic propulsive contractions. Endogenous CGRP plays a role in determining CMC frequency, whereas further unidentified signaling pathways may determine their amplitude and duration.NEW & NOTEWORTHY The colonic motor complex (CMC) initiates propulsion in guinea pig colon. Here, CMCs evoked by an intraluminal pellet were restored during nicotinic receptor blockade by pharmacological agents that directly or indirectly enhance intrinsic primary afferent neuron (IPAN) excitability. IPANs are the only enteric neuron in colon that contain CGRP. Blocking CGRP receptors decreased CMC frequency, implicating their role in CMC initiation. The results support a role for IPANs in the initiation of CMCs.
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Affiliation(s)
- Timothy J Hibberd
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Marcello Costa
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - David J Smolilo
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Lauren J Keightley
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Simon J Brookes
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Phil G Dinning
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Nick J Spencer
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
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Annahazi A, Schemann M. From watery and fluffy to soft and formed: What shapes our stool? J Physiol 2021; 599:4521-4522. [PMID: 34542172 DOI: 10.1113/jp282280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
- Anita Annahazi
- Human Biology, Technical University Munich, Freising, Germany
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