In vitro cytochemical studies of the golgi apparatus of pancreatic acinar cells exposed to drugs that inhibit the transport of membranes and proteins.
In a preceding article, we described alterations occurring in rat pancreas acinar cells at successive post-mortem (PM) intervals. In ultra-thin sections from samples obtained from 0.5, 1, 2, 4, 8 and 12 h, we observed in the Golgi apparatus the appearance of an anomalous membrane bound structure. Such structures are formed by tubules and vesicles that we have called tubular vesicular structure (TVS), and they are frequently located in the position corresponding to the 4th cisterna of the Golgian cisternal pile. Lobules of rat pancreas, incubated in vitro with metabolic inhibitors (such as antimycin A, sodium fluoride, sodium azide and potassium cyanide), were processed in order to be compared with the PM samples of the rat acinar cells. In sliced pieces of lobules, acid phosphatase (AcPase) and tiaminopirophosphatase (TPPase) activity were evaluated. Except for the potassium cyanide treatment, we frequently observed the TVS located at the position corresponding to the 4th cisternae (similar to those observed in the PM acinar cells). These TVS's are predominantly TPPase positive. Based on this result and the fact that the TVS's are surrounded by a membrane (as confirmed by the freeze-fracture replica results) with no structural elements inside, they seem not to correspond to autophagosomes. The TVS's, observed either at PM consecutive times or incubated with metabolic inhibitors, seem to be structures formed in response to ATP deprivation. In 0,5 h PM cells and in cells incubated for 30 and 60 min with metabolic inhibitors, the subcellular structures reacted for AcPase in the rigid lamellae, CV and lysosomes.
Iwamura
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Department of Pathology, Faculty of Medicine, University of São Paulo, Brazil. ceiof@uol.com.br
Nascimento
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Sesso
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D000135:Acid Phosphatase / Q000032:analysis / Q000037:antagonists & inhibitors; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D000968:Antimycin A / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005614:Freeze Fracturing; D006056:Golgi Apparatus / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D006651:Histocytochemistry; D066298:In Vitro Techniques; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism*; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D011190:Potassium Cyanide / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D019810:Sodium Azide / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology; D013834:Thiamine Pyrophosphatase / Q000032:analysis / Q000037:antagonists & inhibitors; D013997:Time Factors
D000963:Antimetabolites; D004791:Enzyme Inhibitors; D026901:Membrane Transport Proteins; D000968:Antimycin A; D012969:Sodium Fluoride; D019810:Sodium Azide; D000135:Acid Phosphatase; D013834:Thiamine Pyrophosphatase; D011190:Potassium Cyanide