Configuration of intestinal slow waves obtained by monopolar recording techniques

Bortoff, A.

doi:10.1152/ajplegacy.1967.213.1.157

Cited by 32 publications

(25 citation statements)

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“…The morphology of the extracellular potential was approximated by the second derivative of the simulated slow wave, which was in agreement with previous studies by Bortoff and others (Figure 7A) (24),(25). The simulation also demonstrated a relationship between the conduction velocity and the amplitude of the extracellular potentials (Figure 7B).…”

Section: Resultssupporting

confidence: 90%

Rapid high‐amplitude circumferential slow wave propagation during normal gastric pacemaking and dysrhythmias

O’Grady

Paskaranandavadivel

et al. 2012

Neurogastroenterology Motil

108

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Background Gastric slow waves propagate aborally as rings of excitation. Circumferential propagation does not normally occur, except at the pacemaker region. We hypothesized that: i) the unexplained high-velocity, high-amplitude activity associated with the pacemaker region is a consequence of circumferential propagation; ii) rapid, high-amplitude circumferential propagation emerges during gastric dysrhythmias; iii) the driving network conductance might switch between ICC-MP and circular ICC-IM during circumferential propagation; iv) extracellular amplitudes and velocities are correlated. Methods An experimental-theoretical study was performed. HR gastric mapping was performed in pigs during normal activation, pacing and dysrhythmia. Activation profiles, velocities and amplitudes were quantified. ICC pathways were theoretically evaluated in a bidomain model. Extracellular potentials were modelled as a function of membrane potentials. Key Results High-velocity, high-amplitude activation was only recorded in the pacemaker region when circumferential conduction occurred. Circumferential propagation accompanied dysrhythmia in 8/8 experiments, was faster than longitudinal propagation (8.9 vs 6.9 mm/s; p=0.004), and of higher amplitude (739 vs 528 μV; p=0.007). Simulations predicted that ICC-MP could be the driving network during longitudinal propagation, whereas during ectopic pacemaking, ICC-IM could outpace and activate ICC-MP in the circumferential axis. Experimental and modeling data demonstrated a linear relationship between velocities and amplitudes (p<0.001). Conclusions & Inferences The high-velocity and high-amplitude profile of the normal pacemaker region is due to localized circumferential propagation. Rapid circumferential propagation also emerges during a range of gastric dysrhythmias, elevating extracellular amplitudes and organizing transverse wavefronts. One possible explanation for these findings is bidirectional coupling between ICC-MP and circular ICC-IM networks.

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Section: Resultssupporting

confidence: 90%

Rapid high‐amplitude circumferential slow wave propagation during normal gastric pacemaking and dysrhythmias

O’Grady

Paskaranandavadivel

et al. 2012

Neurogastroenterology Motil

108

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“…†P Ͻ 0.05, pacemaker area or antrum compared with fundus or corpus (Tukey). It is important to note that the extracellular recording technique used in this study only records the extracellular current generated by the depolarization of the slow wave potential and does not record the plateau nor the repolarization phase of the slow wave (4,5,17). Furthermore, because the dimension of the electrode tip (0.3 mm diameter) is quite large compared with the size of the cells, the potentials recorded are the sum of the depolarization of hundreds of cells in the recorded region.…”

Section: Methodsmentioning

confidence: 99%

Origin and propagation of the slow wave in the canine stomach: the outlines of a gastric conduction system

Lammers¹,

Donck²,

Stephen³

et al. 2009

American Journal of Physiology-Gastrointestinal and Liver Physi

115

178

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Slow waves are known to originate orally in the stomach and to propagate toward the antrum, but the exact location of the pacemaker and the precise pattern of propagation have not yet been studied. Using assemblies of 240 extracellular electrodes, simultaneous recordings of electrical activity were made on the fundus, corpus, and antrum in open abdominal anesthetized dogs. The signals were analyzed off-line, pathways of slow wave propagation were reconstructed, and slow wave velocities and amplitudes were measured. The gastric pacemaker is located in the upper part of the fundus, along the greater curvature. Extracellularly recorded slow waves in the pacemaker area exhibited large amplitudes (1.8 +/- 1.0 mV) and rapid velocities (1.5 +/- 0.9 cm/s), whereas propagation in the remainder of the fundus and in the corpus was slow (0.5 +/- 0.2 cm/s) with low-amplitude waveforms (0.8 +/- 0.5 mV). In the antrum, slow wave propagation was fast (1.5 +/- 0.6 cm/s) with large amplitude deflections (2.0 +/- 1.3 mV). Two areas were identified where slow waves did not propagate, the first in the oral medial fundus and the second distal in the antrum. Finally, recordings from the entire ventral surface revealed the presence of three to five simultaneously propagating slow waves. High resolution mapping of the origin and propagation of the slow wave in the canine stomach revealed areas of high amplitude and rapid velocity, areas with fractionated low amplitude and low velocity, and areas with no propagation; all these components together constitute the elements of a gastric conduction system.

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“…Techniques such as pressure or suction electrodes 2–4 and sucrose gap 5–7 are limited in use today, but intracellular microelectrodes, 8,9 metal extracellular electrodes 10–12 and electrogastrogram (EGG) 13–17 are used widely. Intracellular recording with microelectrodes provides measurements of resting membrane potentials and high fidelity recordings of common electrical behaviors of gastrointestinal (GI) smooth muscles such as slow waves and action potentials.…”

Section: Introductionmentioning

confidence: 99%

“…Measurements of membrane potential and amplitudes of transmembrane electrical events cannot be obtained from extracellular recording, 4 but it is widely thought that the frequency of electrical events can be recorded with fidelity. Based on this belief, EGG is used clinically to evaluate electrical rhythmicity in patients.…”

Section: Introductionmentioning

confidence: 99%

Movement based artifacts may contaminate extracellular electrical recordings from GI muscles

Bayguinov

Hennig

Sanders

2011

Neurogastroenterology &Amp; Motility

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Background Electrical slow waves drive peristaltic contractions in the stomach and facilitate gastric emptying. In gastroparesis and other disorders associated with altered gastric emptying, motility defects have been related to altered slow wave frequency and disordered propagation. Experimental and clinical measurements of slow waves are made with extracellular or abdominal surface recording. Methods We tested the consequences of muscle contractions and movement on biopotentials recorded from murine gastric muscles with array electrodes and pairs of silver electrodes. Key Results Propagating biopotentials were readily recorded from gastric sheets composed of the entire murine stomach. The biopotentials were completely blocked by nifedipine (2 μmol L−1) that blocked contractile movements and peristaltic contractions. Wortmannin, an inhibitor of myosin light chain kinase, also blocked contractions and biopotentials. Stimulation of muscles with carbachol increased the frequency of biopotentials in control conditions but failed to elicit biopotentials with nifedipine or wortmannin present. Intracellular recording with microelectrodes showed that authentic gastric slow waves occur at a faster frequency typically than biopotentials recorded with extracellular electrodes, and electrical slow waves recorded with intracellular electrodes were unaffected by suppression of movement. Electrical transients, equal in amplitude to biopotentials recorded with extracellular electrodes, were induced by movements produced by small transient stretches (<1 mm) of paralyzed or formalin fixed gastric sheets. Conclusions & Inferences These data demonstrate significant movement artifacts in extracellular recordings of biopotentials from murine gastric muscles and suggest that movement suppression should be an obligatory control when monitoring electrical activity and characterizing propagation and coordination of electrical events with extracellular recording techniques.

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Configuration of intestinal slow waves obtained by monopolar recording techniques

Cited by 32 publications

References 0 publications

Rapid high‐amplitude circumferential slow wave propagation during normal gastric pacemaking and dysrhythmias

Rapid high‐amplitude circumferential slow wave propagation during normal gastric pacemaking and dysrhythmias

Origin and propagation of the slow wave in the canine stomach: the outlines of a gastric conduction system

Movement based artifacts may contaminate extracellular electrical recordings from GI muscles

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