Amylase release from streptolysin O-permeabilized pancreatic acinar cells. Effects of Ca2+, guanosine 5'-[gamma-thio]triphosphate, cyclic AMP, tetanus toxin and botulinum A toxin.
The molecular requirements for amylase release and the intracellular effects of botulinum A toxin and tetanus toxin on amylase release were investigated using rat pancreatic acinar cells permeabilized with streptolysin O. Micromolar concentrations of free Ca2+ evoked amylase release from these cells. Maximal release was observed in the presence of 30 microM free Ca2+. Ca(2+)-stimulated, but not basal, amylase release was enhanced by guanosine 5'-[gamma-thio]triphosphate (GTP[S]) (3-4 fold) or cyclic AMP (1.5-2 fold). Neither the two-chain forms of botulinum A toxin and tetanus toxin, under reducing conditions, nor the light chains of tetanus toxin, inhibited amylase release triggered by Ca2+, or combinations of Ca2+ + GTP[S] or Ca2+ + cAMP. The lack of inhibition was not due to inactivation of botulinum A toxin or tetanus toxin by pancreatic acinar cell proteolytic enzymes, as toxins previously incubated with permeabilized pancreatic acinar cells inhibited Ca(2+)-stimulated [3H]noradrenaline release from streptolysin O-permeabilized adrenal chromaffin cells. These data imply that clostridial neurotoxins inhibit a Ca(2+)-dependent mechanism which promotes exocytosis in neural and endocrine cells, but not in exocrine cells.
Stecher
B
B
Abteilung Anatomie und Zellbiologie, Universität Ulm, Germany.
Ahnert-Hilger
G
G
Weller
U
U
Kemmer
T P
TP
Gratzl
M
M
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins; D001905:Botulinum Toxins / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability; D000242:Cyclic AMP / Q000494:pharmacology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D010179:Pancreas / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013301:Streptolysins / Q000494:pharmacology*; D013744:Tetanus Toxin / Q000494:pharmacology
D001426:Bacterial Proteins; D013301:Streptolysins; D013744:Tetanus Toxin; C025964:streptolysin O; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000242:Cyclic AMP; D000681:Amylases; D001905:Botulinum Toxins; D002118:Calcium; D009638:Norepinephrine