Ultrastructural changes induced by 12-O-tetradecanoylphorbol 13-acetate in pure cholinergic synaptosomes of Torpedo electric organ.
We have studied the morphological changes induced by the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) treatment on pure cholinergic synaptosomes from Torpedo electric organ. These changes were studied by both ultrathin sections and freeze-fracture techniques. We found that after a treatment with TPA, a redistribution of synaptic vesicles inside the nerve endings and exocytotic images could be observed. Also, TPA, under conditions that induced the acetylcholine release, did not change the density of intramembrane particles at the synaptosomal protoplasmic hemimembrane leaflet. Similar results were found when calcium was not present in the extrasynaptosomal medium, and our results suggest that acetylcholine release induced by phorbol ester is probably mediated by exocytosis of synaptic vesicles.
Hospital de Bellvitge, Departament de Biología Cel.lular i Anatomía Patològica, Facultat de Medicina, Universitat de Barcelona, Spain.
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Egea
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Guitart
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Marsal
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004557:Electric Organ / Q000187:drug effects / Q000648:ultrastructure*; D005614:Freeze Fracturing; D007365:Intercellular Junctions / Q000187:drug effects / Q000648:ultrastructure; D008854:Microscopy, Electron; D010703:Phorbol Esters / Q000494:pharmacology; D013572:Synaptic Vesicles / Q000187:drug effects / Q000648:ultrastructure; D013574:Synaptosomes / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014101:Torpedo
D010703:Phorbol Esters; C008876:phorbol-12,13-didecanoate; D000109:Acetylcholine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium