Emerging Concepts in Ion Channel Biophysics

Emerging Concepts in Ion Channel Biophysics

Poster Abstracts

54-POS Board 54 Visualizing Calcium Nanodomains in Living Cells through Ion Channel Optical- Recordings. Jose P. Ocelotl-Oviedo 1 , Adán O. Guerrero-Cárdenas 2 , Jose D. Martínez-Reyes 3 , Ángel G. Velasco-Félix 2 , Juan García-Rincon 2 , Carlos E. Batián-Eugenio 4 , Luis Vaca-Domínguez 4 , Alberto Darszon 1 . 1 Biotechnology Institute, Cuernavaca, Morelos, Cuernavaca, Mexico, 2 National Advanced Microscopy Laboratory, Cuernavaca, Morelos, Mexico, 3 Genomics Science Centre, Cuernavaca, Morelos, Mexico, 4 Cellular Physiology Institute, Mexico City, Mexico. Calcium plays a pivotal role in cell physiology as it acts as a second messenger in many signaling processes. Calcium signaling is tightly regulated through the generation of highly localized signals. Single channel activity has been widely studied using patch clamp techniques and a variety of single Ca 2+ channel activities studied. Nevertheless, cells with complex morphologies and Ca 2+ channels with very small single channel conductances (i.e. SOCs) still present a challenge for patch champ techniques. We present a non-invasive methodology, based on the optical recordings of fluorescent calcium probes using total internal reflexion microscopy which allows studying single Ca 2+ channel activity in living cells. Furthermore, we extended the theory of non-stationary noise analysis of macroscopic currents, developed by (Sigworth. J. Physiol. 307:97. 1980), to provide reliable estimates of the number of ion channels in optical patch clamp recordings. Theoretical (Markov Chain Models of single channel activity) and experimental studies of optical path clamp recordings of Ca2+ channels (genetically encoded P2X4 fluorescent channels) are presented as case studies.

Acknowledgements: This work was supported by CONACyT and PAPIIT/UNAM to LV, AD and AG.

The results will be discussed.

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