title: Mastoparan evokes exocytosis without Ca2+ movement in adrenal chromaffin cells.
abstract: The secretagogue action of mastoparan, a tetradecapeptide from wasp venom, was studied in adrenal chromaffin cells. Pulsatile stimulation with mastoparan evoked a sharp transient release of CA in a dose-dependent manner, as measured by real-time monitoring system. The secretagogue action of mastoparan in these cells was apparently independent of extracellular Ca2+, and may not require the intracellular mobilization of Ca2+ since BAPTA failed to block its secretagogue action. Video-imaging data also suggested that mastoparan evokes CA release without an increase in the intracellular Ca2+. In addition, visualization of exocytotic events with video-enhanced light microscopy demonstrated that CA release evoked by mastoparan at relatively low concentration was indeed mediated by exocytotic process, not by cell lysis.
authors.affiliation: Life Science Institute, Sophia University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kumakura
authors.forename: M
authors.initials: M
authors.lastname: Ohara-Imaizumi
authors.forename: S
authors.initials: S
authors.lastname: Muramatsu
authors.forename: S
authors.initials: S
authors.lastname: Terakawa
authors.forename: T
authors.initials: T
authors.lastname: Kanno
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004594:Electrophysiology; D004759:Enterochromaffin Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005089:Exocytosis / Q000187:drug effects*; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D014862:Wasp Venoms / Q000494:pharmacology*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D014862:Wasp Venoms; D004533:Egtazic Acid; C037500:mastoparan; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium