Fast local temperature tracking in electrophysiological preparations by means of controlled laser irradiation

The design and application of a temperature-tracking apparatus using a laser as heating source for electrophysiological preparation are presented. The apparatus provides the ability to follow a given temperature pattern at a local site. The studies were conducted to understand the mechanisms underlying thermal damage to ion channels in the frog nerve node of Ranvier. Main objectives of the temperature controller design are short temperature rise time and precise static temperature control. The temperature controller allows a minimum rise time of 150 ms with an accuracy of in the nerve membrane of nodes of Ranvier. The application of the device to nerve membrane thermal damage study showed that after a 5-second exposure to laser-induced hyperthermia at temperature of 48-54°C, there was a differential suppression of Na and K currents in the nodal membrane currents. Potential applications of the temperature controller design can be found in other research areas in medicine and biophysics that require a stable high temperature heat source for local heating.