A SIMPLE, LOW-COST AND FAST PELTIER THERMOREGULATION SET-UP FOR ELECTROPHYSIOLOGY

Most of the parameters recorded in electrophysiology are strongly temp erature dependent. In order to control temperature fluctuations we hav e built a system that ensures an accurate thermoregulation of the reco rding chamber. Temperature of physiological preparations can be change d relatively quickly (about 8 degrees C/min) and with a good accuracy (+/- 0.5 degrees C) without inducing thermal oscillations. Contrary to other thermoregulating devices, the temperature regulation is not car ried out through the perfused medium but directly at the bottom of the chamber where a 3-cm(2) Peltier element has been placed. The element is driven by a dedicated electronic device which controls the amount a nd the direction of the current flowing across the Peltier thermocoupl e. All construction details and the appropriate electrical circuits ar e provided. Using this home-made device, the steady-state chamber temp erature could be precisely monitored with a resolution of +/- 0.1 degr ees C in a range of 0-40 degrees C. This set-up was tested in experime nts designed to evaluate the temperature dependence of synaptic transm ission in the Torpedo nerve-electroplate synapses and of calcium curre nts recorded from isolated nerve cells. This low-cost method is suitab le for a wide range of applications. (C) 1998 Elsevier Science B.V. Al l rights reserved.