Effects of sphingomyelin hydrolysis on quantal release from rat adrenal chromaffin cells

  • Author / Creator
    Yin, Jihuan
  • Sphingomyelin (SM), a sphingolipid that is concentrated in the extracellular leaflet of the plasma membrane, can interact with cholesterol to form more ordered “raft” domains. The hydrolysis of SM by sphingomyelinase (SMase) generates ceramide and may redistribute cholesterol molecules to other less ordered domains. I employed carbon fibre amperometry to examine whether SM hydrolysis affected the kinetics of release of catecholamines from individual granules of rat chromaffin cells when exocytosis was triggered by elevated extracellular [K+]. Similar to cholesterol overload, SMase treatment selectively increased the proportion of “stand-alone foot” signals and the duration of the “pre-spike foot” signals; both effects could be reduced by extraction of cellular cholesterol. In contrast, the application of an exogenous ceramide did not mimic the effects of SMase. My results suggest that SMase treatment liberated cholesterol from lipid rafts to increase the persistence of the semi-stable fusion pore before the onset of rapid dilation.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Centre for Neuroscience
  • Supervisor / co-supervisor and their department(s)
    • Tse, Fred (Pharmacology)
    • Tse, Amy (Pharmacology)
  • Examining committee members and their departments
    • Smith, Peter (Pharmacology)
    • Baker, Glen (Psychiatry)