Demonstration of Acetylcholinesterase Molecular Forms in a Continuous Tubular Lysosomal System of Rat Pancreatic Acinar Cells

Abstract

S U M M A R Y By applying the highly sensitive cytochemical Gautron's technique, we were able to reveal AChE activity in rat pancreatic acinar cells, particularly at the level of a complex membrane-bound network formed by tubules with varicosities located around the nuclei and close to the basolateral membrane. The Golgi apparatus was devoid of cytochemical reaction beside the trans -Golgi network cisternae, which showed a positive reaction. The RER of some acinar cells also presented a signal, demonstrating their capability of synthesizing AChE. Immunogold using a specific anti-AChE antibody yielded similar results. Double-labeling experiments corroborated the presence of enzyme cytochemical and immunocytochemical signals in the same lysosomal tubular network. Biochemical sedimentation assays confirmed the presence of AChE in acinar cells, which exists as two globular molecular forms, G 1 and G 4 . These results were obtained with pancreatic tissue in situ as well as with isolated acinar cells maintained in culture and devoid of neural elements. The existence of a continuous tubular lysosomal network containing AChE is in agreement with previous reports on acinar and other cell types, and supports a more general hypothesis on dynamic continuities among cell structures. Whether AChE is being secreted by the acinar cells or internalized through this endo-lysosomal system was not defined. However, the capability of the acinar cells to synthesize AChE and to channel it through a tubular system is a good indication that the cells can modulate their cholinergic stimulation for optimal secretion of digestive enzymes. (J Histochem Cytochem 49: 29 -39, 2001)

The properties of acidic compartments in developing schistosomula ofSchistosoma mansoni

“…Despite the use of the sophisticated software (OpenLab), in some regions it was difficult to delineate individual compartments. The presence of a tubular lysosomal network consisting of an endosomal-lysosomal system that could be involved in the uptake and degradation of endocytosed material has been found in rat pancreatic acinar cells (Bendayan & Gisiger, 2001), human hepatocytes (Runnegar et al 1997) and macrophages (Punturieri et al 2000). It is possible that the patchy areas observed in the present study may represent part of a large lysosomal network in schistosomula.…”

Heterotrimeric kinesin‐2, together with kinesin‐1, steers vesicular acetylcholinesterase movements toward the synapse

“…AChE performs multiple functions at diverse locations within a tissue (2,3,52). In addition to the enrichment at the synaptic cleft and neuromuscular junctions, the enzyme is also localized on the neuronal cell membrane and is secreted from neuronal and non-neuronal cells (1,51,53). Therefore, the freshly synthesized AChE that exits the Golgi apparatus needs to be sorted into multiple compartments.…”

Morphological and cytochemical aspects of capillary permeability

“…ϫ26,000. mal compartment is now considered a complex network of tubules in continuous dynamic activity (Araki et al, 1989;Bendayan and Gisiger, 2001;Beaudoin et al, 1984Beaudoin et al, , 1985Cole and Lippincott-Schwartz, 1995;Marsh et al, 1986;Oliver, 1983;Robinson and Karnovsky, 1991;Sandborn and Bendayan, 1996;Swanson et al, 1987a, b;Tooze and Hollinshead, 1991). It, therefore, follows that transendothelial transport could take place through a dynamic tubulo-vesicular system that is highly versatile due to membrane plasticity.…”