scholarly journals Pyeloureteric peristalsis: role of atypical smooth muscle cells and interstitial cells of Cajal-like cells as pacemakers

2006 ◽  
Vol 576 (3) ◽  
pp. 695-705 ◽  
Author(s):  
Richard J. Lang ◽  
Mary A. Tonta ◽  
Beata Z. Zoltkowski ◽  
William F. Meeker ◽  
Igor Wendt ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Interstitial Cells Of Cajal ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Cells Of Cajal

Neuromuscular structures in opossum esophagus: role of interstitial cells of Cajal

1984 ◽  
Vol 246 (3) ◽  
pp. G305-G315 ◽  
Author(s):  
E. E. Daniel ◽  
V. Posey-Daniel
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Interstitial Cells Of Cajal ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Complete Relaxation ◽  
Granular Vesicles ◽  
Cells Of Cajal

The structures of the lower esophageal sphincter (LES) and body circular muscle (BCM) from opossum were compared as to neural and muscular structures and the structural relations of interstitial cells of Cajal to nerves and muscle cells. Both LES and BCM were densely innervated by nerves with varicosities containing many small agranular vesicles and a few large granular vesicles. These nerves were more closely related structurally to the interstitial cells of Cajal than to smooth muscle cells. More gap junctions were observed between smooth muscle cells and between interstitial cells of Cajal and smooth muscle cells in BCM than in LES. Those between smooth muscle cells were larger in BCM. Complete relaxation of the LES strip by isoproterenol reduced these differences but did not eliminate them. The finding that interstitial cells of Cajal often had gap-junction contacts to smooth muscle and close associations with nerves is consistent with the hypothesis that interstitial cells are intercalated between the nerves and muscles and may mediate nerve responses. These findings also suggest that LES muscle cells may be less well coupled electrically than BCM muscle cells.

Role of Ano1 Ca2+-activated Cl− channels in generating urethral tone

2021 ◽  
Vol 320 (4) ◽  
pp. F525-F536
Author(s):  
Bernard T. Drumm ◽  
Keith D. Thornbury ◽  
Mark A. Hollywood ◽  
Gerard P. Sergeant
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Interstitial Cells Of Cajal ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Anoctamin 1 ◽  
Cl Channels ◽  
Experimental Approaches ◽  
Cells Of Cajal

Studies from rabbit show that anoctamin-1 (Ano1) channels expressed in urethral interstitial cells of Cajal (ICCs) serve as a source of depolarization for smooth muscle cells, increasing excitability and tone. However, the role of urethral Ano1 channels is unclear, owing to differences in the species examined and experimental approaches. We summarize findings from different species on the role of urethral ICC and Ano1 channels in urethral contractility and outline proposals for clarifying this topic using cell-specific optogenetic approaches.

Inhibitory innervation of colonic smooth muscle cells and interstitial cells of Cajal

1990 ◽  
Vol 68 (3) ◽  
pp. 447-454 ◽  
Author(s):  
Jan D. Huizinga ◽  
Irene Berezin ◽  
Edwin E. Daniel ◽  
Edwin Chow
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Action Potentials ◽  
Interstitial Cells Of Cajal ◽  
Reversal Potential ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Equilibrium Potential ◽  
Cells Of Cajal

The effect of neural inhibition on the electrical activities of circular and longitudinal colonic smooth muscle was investigated. In addition, a comparative study was carried out between circular muscle preparations with and without the "submucosal" and "myenteric plexus" network of interstitial cells of Cajal (ICC) to study innervation of the "submucosal" ICC and to investigate whether or not the ICC network is an essential intermediary system for inhibitory innervation of smooth muscle cells. Electrical stimulation of intrinsic nerves in the presence of atropine caused inhibitory junction potentials (ijps) throughout the circular and longitudinal muscle layers. The ijp amplitude depended on the membrane potential and not on the location of the muscle cells with respect to the ICC network. Neurally mediated inhibition of the colon resulted in a reduction in amplitude and duration of slow wave type action potentials in circular and abolishment of spike-like action potentials in longitudinal smooth muscle, both resulting in a reduction of contractile activity. With respect to mediation by ICC, the study shows (i) "submucosal" ICC receive direct inhibitory innervation and (ii) circular smooth muscle cells can be directly innervated by inhibitory nerves without ICC as necessary intermediaries. The reversal potential of the ijp in colonic smooth muscle was observed to be approximately −76 mV, close to the estimated potassium equilibrium potential, suggesting that the nerve-mediated hyperpolarization is caused by increased potassium conductance.Key words: enteric nerves, potassium conductance, pacemaker activity, VIP, inhibitory junction potential.

Are interstitial cells of Cajal plurifunction cells in the gut?

2008 ◽  
Vol 294 (2) ◽  
pp. G372-G390 ◽  
Author(s):  
Sushil K. Sarna
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Interstitial Cells Of Cajal ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Slow Waves ◽  
Enteric Neurons ◽  
Motility Disorders ◽  
Cells Of Cajal

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, excitation-contraction 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.

Neuromuscular structures specific to the submucosal border of the human colonic circular muscle layer

1990 ◽  
Vol 68 (11) ◽  
pp. 1437-1446 ◽  
Author(s):  
M. S. Faussone-Pellegrini ◽  
C. Cortesini ◽  
D. Pantalone
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Interstitial Cells Of Cajal ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Muscle Layer ◽  
Interstitial Cells ◽  
Circular Muscle Layer ◽  
The Right ◽  
Cells Of Cajal

The circular muscle layer of the human caecum and ascending colon is clearly subdivided into two portions: an outer one which includes the bulk of the circular muscle layer, and an inner one made up of only six to eight rows of cells. In the right transverse colon no demarcation can be observed, but a difference exists between the innermost and the outermost cells, since those of the two innermost rows possess some peculiarities with regard to the sarcoplasmic reticulum, glycogen particles, caveolae, and intercellular junctions. In the left part of the colon, the circular muscle layer is also divided into two portions. In fact, the innermost smooth muscle cells still possess peculiar morphologies, progressively increase in number, and become separate from each other making up a superficial muscle network. A fibrous lamella, along and inside which a ganglionated nerve plexus runs, is strictly apposed to the submucosal border of the circular muscle layer of the entire colonic length. A second nerve plexus runs between the two portions of the circular muscle layer. Both these plexuses are accompanied by interstitial cells of Cajal in the right colon only. The peculiar organization of the entire submucosal border of the human colonic circular muscle layer distinguishes it from other parts of the gut and probably represents a structural basis for control of human colonic motility. The presence of putative pacemaker cells (interstitial cells and peculiar smooth muscle cells) indicates that the inner border of human colonic circular muscle layer possesses pacemaking activities. Moreover, the interstitial cell – smooth muscle cell ratio differs depending on the colonic level; two main regions can be identified: the right and the left colon. Consequently, we might expect regional variation in pacemaking.Key words: smooth muscle cells, interstitial cells of Cajal, human colon, ultrastructure.

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