A5051689359- Gastrointestinal motility and disorders
- Ion Transport and Channel Regulation
- Ion channel regulation and function
- Cardiac electrophysiology and arrhythmias
- Ion Channels and Receptors
- Neuroscience and Neural Engineering
- Nonlinear Dynamics and Pattern Formation
- Diet and metabolism studies
- Neural dynamics and brain function
- Plant and Biological Electrophysiology Studies
- Infant Health and Development
- Gastroesophageal reflux and treatments
- Neuroscience and Music Perception
- Respiratory viral infections research
- Influenza Virus Research Studies
- Helicobacter pylori-related gastroenterology studies
- Congenital gastrointestinal and neural anomalies
- Pelvic floor disorders treatments
- Neuroscience of respiration and sleep
- COVID-19 epidemiological studies
- Neuroscience and Neuropharmacology Research
- Heart Rate Variability and Autonomic Control
- Mass Spectrometry Techniques and Applications
- Neuropeptides and Animal Physiology
- Advanced Thermodynamics and Statistical Mechanics
McMaster University
2013-2023
Population Health Research Institute
2013-2023
Digestive Health Research Institute
2012
University of Nevada, Reno
2008
St George's, University of London
2002-2003
St George's Hospital
2002-2003
Queen's Medical Centre
1992
The role of short-chain fatty acids (SCFAs) in the control colonic motility is controversial. Germ-free (GF) mice are unable to produce these metabolites and serve as a model study how their absence affects motility. GF transit slower than controls, colonization improves serotonin [5-hydroxytryptamine (5-HT)] levels. Our aim was determine SCFAs play improving whether this dependent on mucosal 5-HT signaling. Motility assessed via spatiotemporal mapping. First, motor patterns whole colon were...
Normal motility of the colon is critical for quality life and efforts to normalize abnormal function have had limited success. A better understanding control systems colonic therefore essential. We report here a hypothesis with supporting experimental data explain origin rhythmic propulsive motor activity induced by general distention. The theory holds that both networks interstitial cells Cajal (ICC), those associated submuscular plexus (ICC-SMP) myenteric (ICC-MP), orchestrate propagating...
Simultaneous pressure waves (SPWs) in manometry recordings of the human colon have been associated with gas expulsion. Our hypothesis was that SPW might be a critical component most colonic motor functions, and hence act as biomarker for healthy motility. To end, we performed high-resolution (HRCM), first time using an 84-sensor (1 cm spaced) water-perfused catheter, 17 volunteers. Intraluminal patterns were recorded during baseline, proximal rectal balloon distention, after meal following...
Characterization of high-amplitude propagating pressure waves (HAPWs or HAPCs) plays a key role in diagnosis colon dysmotility using any type colonic manometry. With the introduction high-resolution manometry, more insight is gained into this most prominent propulsive motor pattern. Here, we use water-perfused catheter with 84 sensors intervals between measuring points 1 cm throughout colon, for 6–8 h, 19 healthy subjects. The contained balloon to evoke distention. We explored as stimuli...
Abstract Background High‐resolution colonic manometry gives an unprecedented window into motor patterns of the human colon. Our objective was to characterize activities throughout entire colon that possessed persistent rhythmicity and spanning at least 5 cm. Methods using 84‐channel water‐perfused catheter performed in 19 healthy volunteers. Rhythmic activity assessed during baseline, proximal balloon distention, meal, bisacodyl administration. Key Results Throughout colon, a cyclic pattern...
What is the central question of this study? are effects interstitial cells Cajal (ICC) network perturbations on intestinal pacemaker activity and motor patterns? main finding its importance? Two-dimensional modelling ICC according to a phase model weakly coupled oscillators showed that properties (coupling strength between oscillators, frequency gradient noise) strongly influence subsequent patterns. The explains patterns observed in physiological conditions provides predictions testable...
Waves of contraction in the small intestine correlate with slow waves generated by myenteric network interstitial cells Cajal. Coupled oscillator theory has been used to explain steplike gradients frequency (frequency plateaux) along length intestine. Inhibition gap junction coupling between oscillators should lead predictable effects on these plateaux and wave dislocation (wave drop) phenomena associated their boundaries. It is predictions that we wished test. We a novel multicamera...
Phase-amplitude coupling of two pacemaker activities the small intestine, omnipresent slow wave activity generated by interstitial cells Cajal myenteric plexus (ICC-MP) and stimulus-dependent rhythmic transient depolarizations ICC deep muscular (ICC-DMP), was recently hypothesized to underlie orchestration segmentation motor pattern. The aim present study increase our understanding phase-amplitude through modeling. In particular importance propagation velocity ICC-DMP component investigated....
Pacemaker activities generated by networks of interstitial cells Cajal (ICC), in conjunction with the enteric nervous system, orchestrate most motor patterns gastrointestinal tract. It was our objective to understand role network features ICC associated myenteric plexus (ICC-MP) shaping small intestine. To that end, a model weakly coupled oscillators (oscillators influence each other's phase but not amplitude) created parameters derived from experimental data. The is uniform two dimensional...
Hydrogen sulphide (H2 S) is an endogenous gaseous signalling molecule with putative functions in gastrointestinal motility regulation. Characterization of H2 S effects on colonic crucial to establish its potential use as therapeutic agent the treatment disorders.H2 were characterized using video recordings and construction spatio-temporal maps. Microelectrode muscle bath studies performed investigate mechanisms underlying effects. NaHS was used source S.Rhythmic propulsive motor complexes...
Abnormal colonic motility may be associated with dysfunction of the autonomic nervous system (ANS). Our aim was to evaluate if associations between motor patterns and neural activity could demonstrated by assessing changes in heart rate variability (HRV) healthy volunteers. A total 145 were assessed 11 volunteers High-Resolution Colonic Manometry (HRCM) using an 84-channel water-perfused catheter. Motor evoked balloon distention, a meal luminal bisacodyl. The electrocardiogram (ECG) cardiac...
OPINION article Front. Neurosci., 01 April 2013Sec. Autonomic Neuroscience https://doi.org/10.3389/fnins.2013.00043
Ion channels are fundamental to gastrointestinal pacemaking by interstitial cells of Cajal (ICC). Previously, we have recorded a high-conductance chloride channel (HCCC) from ICC, both in culture and situ, associated with the myenteric plexus. The biophysical properties HCCC (conductance, subconductances, voltage- time-dependent inactivation) suggest it is member class called maxi-anion channels. In this study further investigated situ. Our main finding was that not strictly but has relative...
Nitrergic nerves have been proposed to play a critical role in the orchestration of peristaltic activities throughout gastrointestinal tract. In present study, we investigated nitric oxide, using spatiotemporal mapping, activity whole ex vivo mouse intestine. We identified propulsive motor pattern form propagating myogenic contractions, that are clustered by enteric nervous system into minute rhythm is dependent on oxide. The cluster formation was abolished TTX, lidocaine and oxide synthesis...
Background Chloride channels are proposed to play a central role in the electrical pacemaking mechanism of interstitial cells Cajal (ICC). A key unknown factor consideration this is chloride equilibrium potential (ECl), as determined by relative concentrations intra- ([Cl−]i) and extracellular ([Cl−]o) ions. Methods To calculate ECl ICC, [Cl−]i was measured with fluorescent indicator N-(6-methoxyquinolyl) acetoethyl ester (MQAE). Pacemaker ICC explant cultures or situ, i.e. associated...
Interstitial cells of Cajal (ICC) are the pacemakers gut, initiating slow-wave activity. Several ion channels have been identified that contribute to depolarization phase slow wave. Our aim was knowledge about identity and role ICC potassium in pacemaking. Here we describe a transient outward current cell-attached patches ICC. This activated almost instantaneously at potentials positive resting membrane potential inactivated as single exponential or biexponential with time constants varied...
Abstract Background Nitric oxide (NO) mediates inhibitory neurotransmission and is a critical component of neuronal programs that generate propulsive contractions. NO acts via its receptor NO‐sensitive guanylyl cyclase (NO‐GC) which expressed in smooth muscle cells (SMC) interstitial Cajal (ICC). Organ bath studies with colonic rings from NO‐GC knockout mice (GCKO) have indicated to modulate spontaneous The cell‐specific effects on the dominant pan‐colonic contraction, long distance...
New Findings What is the central question of this study ? nature slow wave‐driven contraction frequency gradients in small intestine? main finding and its importance Frequency plateaux are composed discrete waves increased interval, each wave associated with a dislocation. Smooth generated by localized neural modulation frequency, leading to functionally important turbulence. Both patterns emergent properties network coupled oscillators, interstitial cells Cajal. Abstract A gut‐wide Cajal...
Abstract Background Households represent important settings for transmission of influenza and other respiratory viruses. Current diagnosis treatment relies upon patient visits to healthcare facilities, which may lead under‐diagnosis delays. This study aimed assess the feasibility an at‐home approach via home testing, telehealth care, rapid antiviral delivery. Methods We conducted a pilot interventional remote in Seattle‐area households with children during 2019‐2020 season using...
Abstract Background Interstitial cells of Cajal (ICC) associated with the myenteric plexus small intestine express maxi chloride channels. Our aim was to investigate whether or not these channels would be activated by increases in intracellular Ca 2+ , as that strengthen evidence for their potential role ICC pacemaking. A further examine inwardly and outwardly rectifying currents signify different Methods We used Fluo‐4 AM imaging patch clamp electrophysiology (cell‐attached inside‐out) on...
Abstract Background The ICC ‐ DMP have been proposed to generate stimulus‐dependent pacemaker activity, rhythmic transient depolarizations, that take part in orchestrating segmentation and clustered propulsive motor patterns the small intestine. However, little is known about fundamental properties of . Methods This study was undertaken increase our understanding intrinsic through calcium imaging intracellular electrical recordings. Key Results Without stimulation, most were quiescent. In...