MODELLING THE PATCH CLAMP EXPERIMENTAL SETUP ENABLES THE RECOVERY OF NATIVE ELECTROPHYSIOLOGICAL RESPONSES
Gergely Tarcsay1, Viktor János Oláh1, János Szabadics1, János Brunner1
1 Institute of Experimental Medicine, Budapest
Electrophysiological instruments, including pipette and amplifier circuits inevitably distort patch clamp recorded intracellular signals which has a substantial impact in case of small structures, such as small boutons, since their passive properties are comparable to the instrumental electrical contribution. Consequently, recording instruments not only filter the measured biological signals but also affect the local cellular electrogenesis. In order to retrieve the native spikes from small structures, we built and tested an electrical model of the experimental setup that is capable of predicting the biophysical properties of the recorded and reconstructed small biological structure. In one respect, investigating the physical and geometrical properties of patch pipettes led us to represent them as inhomogenous multicompartmental RC-circuits. On the other hand, each element of voltage- and current-clamp circuit were implemented, whose electrical contributions were measured by isolating them within the amplifier circuit. Simulations using our model confirmed that instrumentation indeed have significant impacts on recorded signals. Our results revealed that the predictive native spikes were considerably larger and faster than the measured signals and similar to the theoritically expected signal. As a conclusion, our observations suggests that precise model of the experimental setup allows the retrieval of electrical properties of small neuronal structures from heavily distorted recordings.