BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Quantitative fluorescence imaging with up to 30 nm resolution to p
 rovide 3D data for models of cardiac Ca2+ handling - Soeller\, C (Auckland
 )
DTSTART:20090720T094500Z
DTEND:20090720T100000Z
UID:TALK19185@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Quantitative understanding of the Ca2+ handling in cardiac ven
 tricular myocytes requires accurate knowledge of cardiac ultrastructure an
 d protein distribution. We have therefore developed high-resolution imagin
 g and analysis approaches to measure the three-dimensional distribution of
  immuno-labelled proteins with optical microscopy methods. Until recently 
 optical imaging was thought to be limited to a resolution of ~250 nm set b
 y the diffraction of light. We have overcome this limitation using a new t
 echnique that allows imaging of conventionally labelled fluorescent sample
 s at much higher resolution. Our technique\, called reversible photobleach
 ing microscopy (RPM)\, allows extension to multi-colour and full 3D locali
 zation and provides a new powerful method to study the nanostructure of ca
 rdiac muscle. We have used RPM and confocal microscopy to obtain new insig
 ht into the distribution of ryanodine receptors and related proteins such 
 as the sodium calcium exchanger and caveolin. To investigate potential eff
 ects of myocyte structure on Ca2+ wave propagation we determined the three
 -dimensional distribution of RyR clusters within an extended section of a 
 single rat ventricular myocyte to construct a model of stochastic Ca2+ dyn
 amics with a measured Ca2+ release unit (CRU) distribution. The model with
  a realistic CRU distribution supported Ca2+ waves that spread axially alo
 ng the cell at velocities of ~50 m/s. By contrast\, in a simplified model 
 with planar CRU distribution axial wave spread was slowed ~two-fold and wa
 ve propagation often nearly faltered. These results demonstrate that featu
 res of the CRU distribution on multiple length scales may significantly af
 fect intracellular Ca2+ dynamics and must be captured in detailed mechanis
 tic models to achieve quantitative as well as qualitative insight. 
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR