Hemocytes of Pomacea canaliculata: I. Reversible aggregation induced by Ca2+.
Using a platelet aggregometer, factors involved in hemocyte aggregation of a prosobranch snail Pomacea canaliculata were investigated. Aggregation-inducing tests revealed that extracellular Ca2+ is required to provoke the cellular response which is reversible. The aggregation-dispersion response can be induced by adding Ca2+ and EDTA alternately. Aggregation was inhibited by a calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) in a dose-dependent manner, and by a protein kinase-C inhibitor 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine dihydrochloride (H-7). Thus, calmodulin and protein kinase-C may contribute to the calcium-mediated aggregation of hemocytes, which resembles a phenomenon that occurs in vertebrate leucocytes. Unlike the aggregation of mammalian leucocytes, no stimulus other than Ca2+ is required to induce the response of Pomacea hemocytes. Thus, this system may serve as a simple model for analysing cellular aggregation responses.
Shozawa
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Department of Medical Zoology, Nagoya University School of Medicine, Japan.
Suto
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C
D000818:Animals; D001773:Blood Cells / Q000502:physiology*; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000037:antagonists & inhibitors; D002449:Cell Aggregation / Q000187:drug effects / Q000502:physiology; D006434:Hemocytes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D066298:In Vitro Techniques; D008274:Magnesium / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012908:Snails / Q000276:immunology*
D002147:Calmodulin; D011493:Protein Kinase C; D008274:Magnesium; D002118:Calcium