Schistosoma mansoni: the role of calcium in the stimulation of cercarial proteinase release.
We investigated the role of calcium mobilization in the induction of proteinase release from cercarial preacetabular glands. Proteinase release was measured by the ability of cercariae to break down a 3H-labeled proline extracellular fibroblast matrix and calcium influx was measured using 45Ca2+. The role of calcium in the activation of cercarial proteinase was examined by investigating the effects of calcium addition and removal on linoleate-induced matrix degradation, the ability of various calcium modulators (Verapamil, fendiline, nifedipine, SK-525A, BAY K-8644, Ryanodine, and SK-7171A) to stimulate or inhibit linoleate-induced proteinase release, the ability of calcium modulators directly to induce cercarial proteinase release, and the ability of various stimulants of proteinase release to induce calcium influx or efflux from cercariae. The results of these studies indicate that proteinase release is dependent on external calcium concentration, voltage-operated channels are either nonexistent in cercariae or have a minimal role in overall calcium influx, and that activation of Ca2+ influx can be caused by both free fatty acids and calcium modulators by a hypothesized receptor-operated channel. Although calcium uptake is important in cercarial proteinase release, it is not the only factor involved. Calcium uptake alone does not guarantee that proteinase will be secreted. On the other hand, if Ca2+ influx does not occur, proteinase will not be secreted.
Fusco
A C
AC
Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford 61107.
Salafsky
B
B
Vanderkooi
G
G
Shibuya
T
T
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D010450:Endopeptidases / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000494:pharmacology; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D011335:Proadifen / Q000494:pharmacology; D012433:Ryanodine / Q000494:pharmacology; D012550:Schistosoma mansoni / Q000187:drug effects / Q000201:enzymology*; D014700:Verapamil / Q000494:pharmacology
D008041:Linoleic Acids; D009829:Oleic Acids; D012433:Ryanodine; D019301:Oleic Acid; D000001:Calcimycin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D019787:Linoleic Acid; D011335:Proadifen; D014700:Verapamil; D010450:Endopeptidases; D002118:Calcium