Quantitative Estimation of Calcium Dynamics From Ratiometric Measurements: A Direct, Nonratioing Method

• DOI: 10.1152/jn.00414.2009
• Publication Date: 2009-12-03T03:24:32Z
• Authors: Sébastien Joucla; Andreas Pippow; Peter Kloppenburg; Christophe Pouzat
• Keywords: 0301 basic medicine; Models, Neurological; MESH: Neurons; MESH: Microscopy, Fluorescence; MESH: Calcium Signaling; 03 medical and health sciences; MESH: Computer Simulation; MESH: Models, Neurological; Image Interpretation, Computer-Assisted; Animals; Humans; MESH: Animals; Computer Simulation; Calcium Signaling; Cells, Cultured; [INFO.INFO-BI] Computer Science [cs]/Bioinformatics [q-bio.QM]; Neurons; MESH: Humans; [SDV.BIBS] Life Sciences [q-bio]/Quantitative Methods [q-bio.QM]; [SDV.BIBS]Life Sciences [q-bio]/Quantitative Methods [q-bio.QM]; Microscopy, Fluorescence; MESH: Calcium; Calcium; [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM]; MESH: Image Interpretation, Computer-Assisted; MESH: Cells, Cultured

Measuring variations of intracellular free calcium concentration through the changes in fluorescence a calcium-sensitive dye is ubiquitous technique neuroscience. Despite its popularity, confidence intervals (CIs) on estimated parameters dynamics models are seldom given. To address this issue, we have developed two-stage model for ratiometric measurements obtained with charge-coupled device (CCD) camera. Its first element embeds parametric into intensity and second probabilistically describes by CCD Using Monte Carlo simulations, show that classical transformation gives reliable CIs time constants only not baseline nor influx. We then introduce direct method, which consists fitting directly simultaneously transients at both wavelengths, without any data ratioing. This approach uses probabilistic description camera, leading to construction meaningful parameters. Moreover, using approaches inspired constrained linear regression, can take account finite precision calibrated (such as dissociation constant cell). These key features illustrated simulated simulations. illustrate strength method experimental recordings from insect olfactory interneurons. In particular, how handle time-dependent buffer concentration, thereby considerably improving our goodness fit. The was implemented open-source software R freely distributed CalciOMatic package.