title: Cytoskeletal F-actin, not the circumferential coil of microtubules, regulates platelet dense-body granule secretion.
abstract: Cytoskeletal F-actin assembly and microtubule reorganization are principal cellular events responsible for activation-induced platelet shape change; however, their roles in regulating platelet secretion have remained controversial. Herein, label-free microelectrochemistry techniques and pharmacological approaches are used to probe the role of F-actin and the microtubule in platelet dense-body secretion. Altered microtubule integrity via exposure to paclitaxel or vincristine had no effect on serotonin release in platelet suspensions. Disruption of F-actin by cytochalasin D (CytoD) or latrunculin A (LatA) substantially enhanced the rate of serotonin release, while inhibition of the F-actin-dependent platelet motor protein myosin IIA by blebbistatin had no effect. CytoD-treated platelets also showed enhanced serotonin quantal secretion rate. These results clearly indicate that F-actin, but not the microtubule, regulates platelet dense-body secretion and does so by serving as a physical barrier. This study also demonstrates the promise of microelectrochemistry for giving important insight into platelet quantal secretion mechanisms in future studies.
authors: Department of Chemistry, College of Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors: Shencheng
authors: S
authors: Ge
authors: James G
authors: JG
authors: White
authors: Christy L
authors: CL
authors: Haynes
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology; D015539:Platelet Activation / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012701:Serotonin / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology; D014750:Vincristine / Q000494:pharmacology
chemical_list: D000199:Actins; D050257:Tubulin Modulators; D012701:Serotonin; D014750:Vincristine; D017239:Paclitaxel