Lars Thuneberg

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The pacemaker activity in the mammalian gut is responsible for generating anally propagating phasic contractions. The cellular basis for this intrinsic activity is unknown. The smooth muscle cells of the external muscle layers and the innervated cellular network of interstitial cells of Cajal, which is closely associated with the external muscle layers of(More)
In muscularis externa of mouse small intestine, cells with ultrastructural features of macrophages were invariably observed in three layers: in the subserosal layer, between the circular and longitudinal muscle layers, and in association with the deep circular plexus. These macrophage-like cells (MLC) had a single indented nucleus, perinuclear Golgi(More)
Motility patterns and their structural basis were studied by video analysis, light and electron microscopy on the physiologically distended gut from normal and W/W(v) suckling mice and normal adult mice. Empty or diltiazem-relaxed intestine were used as references. In contrast to conventional primary aldehyde fixation, a brief primary fixation with osmic(More)
The interstitial cell of Cajal, abbreviated ICC, is a specific cell type with a characteristic distribution in the smooth muscle wall throughout the alimentary tract in humans and laboratory mammals. The number of publications relating to ICC is rapidly increasing and demonstrate a rich variation in the structure and organization of these cells. This(More)
The ultrastructure of plexus muscularis profundus (PMP) of the mouse small intestine was investigated subsequent to vascular perfusion with ruthenium red-containing and routine aldehyde fixatives. Four types of nerve terminals were revealed. Type I: numerous 500-A agranular vesicles and few 1,000-A granular vesicles. Type II: predominantly large(More)
Interstitial cells of Cajal (ICCs) have recently been identified as the pacemaker cells for contractile activity of the gastrointestinal tract. These cells generate the electrical 'slow-wave' activity that determines the characteristic frequency of phasic contractions of the stomach, intestine and colon. Slow waves also determine the direction and velocity(More)
Intracellular microelectrodes and organ bath techniques were used to study spontaneous cyclic electrical and mechanical activity in the rat colon. Electron microscopy and immunohistochemical studies showed two major populations of interstitial cells of Cajal (ICC): one associated with Auerbach's plexus (ICC-AP) and one with the submuscular plexus (ICC-SMP).(More)
BACKGROUND It has been suggested that interstitial cells of Cajal (ICC) at the submucosal border of the colonic circular muscle are pacemaker cells. We studied smooth muscle cells and ICC at the submucosal surface of the circular muscle layer of the normal human colon. EXPERIMENTAL DESIGN Resected, unaffected specimens from human colon were studied by(More)
Previous morphological and electrophysiological studies have supported the hypothesis that interstitial cells of Cajal have important regulatory (pacemaker) functions in the gut. In the current study, interstitial cells of Cajal associated with Auerbach's plexus in human small intestine were studied. Freshly resected intestine was examined by light and(More)