A new design of double‐barrelled microelectrodes for intracellular pH‐measurement in vivo

Publisher Website
Google Scholar
Abstract
Intracellular pH (pHi) is one important regulator of cellular function. Most determinations of pHi in vivo have been performed by using indirect methods, e. g. CO2/HCO3 or DMO techniques, since no suitable direct method for reliable in vivo measurements have been available. In the present study a new type of double‐barrelled microelectrode for simultaneous in vivo measurements of pHi and membrane potential (Em) is presented. The electrode was constructed on the basis of a combined recessed‐and pencil‐tip design. The tip diameter of the double‐barrelled microelectrode was about 1.5 μm. The response of the pH channel was 55–60 mV/pH unit and the response time was between 30 s and 1 min. In vivo measurements of pHi and Em of rabbit skeletal muscle fibers are presented. A mean pHi of 7.00 (in 8 animals) at a membrane potential of ‐90.3 mV (arterial pH: 7.30, arterial PCO2: 6.39 kPa) was obtained. The new design of pH microelectrode offers some advantages over previously described microelectrodes and is well suited for in vivo measurements.