Slow waves in circular muscle of porcine ileum: structural and electrophysiological studies

Jiménez, Marcel; Borderies, J.R.; Vergara, Patri; Wang, Y.-F.; Daniel, E. E.

doi:10.1152/ajpgi.1999.276.2.g393

Cited by 18 publications

(32 citation statements)

References 46 publications

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“…Interestingly, slow waves were recorded in the circular muscle layer but it was not possible to make recordings of electrical activity from the longitudinal muscle layer. These results partially concur with the findings of Jiménez et al (1999) who found that slow wave amplitude varied with local membrane potential, suggesting that there may be a voltagedependent component in determining the amplitude of slow waves in the pig, presumably involving voltagesensitive ion channels. Although in this laboratory, Hudson et al (2001b) have recorded slow waves in the longitudinal muscle of equine ileum, to date, their presence has not yet been established in this layer in the pig.…”

Section: Discussionsupporting

confidence: 91%

“…The characteristics of these oscillations correlated well with the slow waves recorded in porcine ileum by other workers (Borderies et al 1997, Ferná ndez et al 1998, Jiménez et al 1999. The characteristics of these oscillations correlated well with the slow waves recorded in porcine ileum by other workers (Borderies et al 1997, Ferná ndez et al 1998, Jiménez et al 1999.…”

Section: Discussionsupporting

confidence: 84%

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Interstitial cells of Cajal and electrical activity of smooth muscle in porcine ileum

2006

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 84%

Interstitial cells of Cajal and electrical activity of smooth muscle in porcine ileum

2006

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“…The reported length and time constants do not explain the nearly simultaneous onset of slow waves through the thickness of the circular muscle layers (Fig. 5B) (72,79,82).…”

Section: The Roles Of Icc In the Generation And Propagation Of Slow Wmentioning

confidence: 81%

Are interstitial cells of Cajal plurifunction cells in the gut?

Sarna¹

2008

American Journal of Physiology-Gastrointestinal and Liver Physi

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The proposed functions of the interstitial cells of Cajal (ICC) are to 1) pace the slow waves and regulate their propagation, 2) mediate enteric neuronal signals to smooth muscle cells, and 3) act as mechanosensors. In addition, impairments of ICC have been implicated in diverse motility disorders. This review critically examines the available evidence for these roles and offers alternate explanations. This review suggests the following: 1) The ICC may not pace the slow waves or help in their propagation. Instead, they may help in maintaining the gradient of resting membrane potential (RMP) through the thickness of the circular muscle layer, which stabilizes the slow waves and enhances their propagation. The impairment of ICC destabilizes the slow waves, resulting in attenuation of their amplitude and impaired propagation.2) The one-way communication between the enteric neuronal varicosities and the smooth muscle cells occurs by volume transmission, rather than by wired transmission via the ICC. 3) There are fundamental limitations for the ICC to act as mechanosensors.4) The ICC impair in numerous motility disorders. However, a cause-and-effect relationship between ICC impairment and motility dysfunction is not established. The ICC impair readily and transform to other cell types in response to alterations in their microenvironment, which have limited effects on motility function. Concurrent investigations of the alterations in slow-wave characteristics, excitationcontraction and excitation-inhibition couplings in smooth muscle cells, neurotransmitter synthesis and release in enteric neurons, and the impairment of the ICC are required to understand the etiologies of clinical motility disorders. smooth muscle; slow waves; enteric neurons; excitation-contraction coupling; peristaltic reflex; motility disorders; volume transmission; synaptic transmission, ICC THE INTERSTITIAL CELLS WERE characterized originally by Raymond V. Cajal (20,21). These cells got his attention and that of others because they are intercalated between the autonomic nerves and the effector cells. On the basis of the understanding of the interneuronal communication in the central nervous system (CNS) at that time, Cajal proposed that the intercalating cells [later called the interstitial cells of Cajal (ICC)] mediate the transmission of signals from the autonomic neurons to the smooth muscle cells. A few years later, Keith (84) observed a collar of similar cells in the myenteric plexus of the rat ileocecal junction. He was looking for a pacemaker of the gut smooth muscle electrical activity because a few years earlier he had identified such a pacemaker in the sinoatrial node of the heart. He hypothesized that those interstitial cells were the pacemaker cells in the gut. In the late 1960s and early 1970s, several investigators described a plexus of the ICC within the myenteric and submucosal plexi of the small and large intestines. They also identified close connections between the enteric axonal varicosities and ICC processes on one side and g...

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“…The conductivity in the ICC-MP was assigned to be homogenous (isotropic) in all directions, in accordance with the intracellular recordings by Hirst et al (16),(18), and calcium imaging studies by Hening et al (21),(22), which have shown that ICC-MP propagates slow waves with equal velocity in all directions. Conduction in the ICC-MP network is slower than in the ICC-IM, despite the relative abundance of gap junctions in ICC-MP network (34). The specified ICC-MP conductivities were σ i = 50 mS mm −1 , σ e = 0.27 mS mm −1 .…”

Section: Circumferential Velocity Component Identificationmentioning

confidence: 99%

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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Slow waves in circular muscle of porcine ileum: structural and electrophysiological studies

Cited by 18 publications

References 46 publications

Interstitial cells of Cajal and electrical activity of smooth muscle in porcine ileum

Interstitial cells of Cajal and electrical activity of smooth muscle in porcine ileum

Are interstitial cells of Cajal plurifunction cells in the gut?

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

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