title: Similar mechanisms regulate protein exocytosis from the salivary glands of ixodid and argasid ticks.
abstract: Numerous bioactive compounds are secreted from large dense core granules in tick salivary glands during feeding in response to an external stimulus. Investigations into the signalling pathways regulating secretion indicated that they are similar for Argasidae (fast-feeding ticks) and Ixodidae (slow-feeding ticks), but differ in their sensitivity to prostaglandin E(2). In both cases, dopamine is the external signal for inducing exocytosis. Dopamine-induced exocytosis was shown to be strongly calcium dependant. Firstly, it requires extracellular calcium via a L-type voltage-gated calcium channel located on the plasma membrane and, secondly, intracellular calcium which is released presumably in response to inositol 1,4,5-triphosphate (IP(3)). Pathways such as the activation of phospholipase C, inositol-phosphate kinases, G-proteins, GTPases and Na(+)-K(+)-ATPases have been shown to be essential.
authors.affiliation: Department of Biochemistry, University of Pretoria, South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Maritz-Olivier
authors.forename: A I
authors.initials: AI
authors.lastname: Louw
authors.forename: A W H
authors.initials: AW
authors.lastname: Neitz
mesh_terms: D000818:Animals; D001081:Apyrase / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000378:metabolism; D015232:Dinoprostone / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism / Q000494:pharmacology; D004963:Estrenes / Q000633:toxicity; D005089:Exocytosis / Q000502:physiology*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism / Q000494:pharmacology; D011760:Pyrrolidinones / Q000633:toxicity; D012469:Salivary Glands / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013019:South Africa; D013045:Species Specificity; D013987:Ticks / Q000502:physiology*; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D020746:Calcium Channels, L-Type; D004963:Estrenes; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D001081:Apyrase; D000254:Sodium-Potassium-Exchanging ATPase; D015232:Dinoprostone; D002118:Calcium; D004298:Dopamine