Electrophysiological Recordings on a Sounding Rocket: Report of a First Attempt Using Xenopus laevis Oocytes

It is not fully understood how cells detect external mechanical forces, but mechanosensitive ion channels play important roles in detecting and translating physical forces into biological responses (mechanotransduction). With the “OoClamp” device, we developed a tool to study electrophysiological processes, including the gating properties of ion channels under various gravity conditions. The “OoClamp” device uses an adapted patch clamp technique and is operational during parabolic flight and centrifugation up to 20 g. In the framework of the REXUS/BEXUS program, we have further developed the “OoClamp” device with the goal of conducting electrophysiological experiments aboard a flying sounding rocket. The aim of such an experiment was first to assess whether electrophysiological measurements of Xenopus laevis oocytes can be performed on sounding rocket flights, something that has never been done before. Second, we aimed to examine the gating properties of ion channels under microgravity conditions. The experiment was conducted in March 2016 on the REXUS 20 rocket. The post-flight analysis showed that all recording chambers were empty as the rocket reached the microgravity phase. A closer analysis of the flight data revealed that the oocytes were ripped apart a few seconds after the rocket launch. This first attempt at using sounding rockets as a research platform for electrophysiological recordings was therefore limited. Our modified “OoClamp” hardware was able to perform the necessary tasks for difficult electrophysiological recordings aboard a sounding rocket; however, the physical stresses during launch (acceleration and vibrations) did not support viability of Xenopus oocytes.