An inexpensive inverted microscope for patch-clamp and other electrophysiological studies at the cellular level.

The popularization of the patch-clamp technique has increased the demand for inverted light microscopes that allow the optimal or almost free movement of patch-clamp pipettes and their support drives. However, commercially available models of inverted microscopes have not been specifically designed for this line of research and, as a consequence, patch-clamp pipette movements are restricted by the small space available between the sample, and the light source and its modulating attachments. This paper provides the details for the construction of a relatively inexpensive inverted microscope that meets the specifications required for patch-clamp and other electrophysiological investigations at the cellular level. The microscope allows the free positioning of the conventional probes for patch-clamp, microelectrode amplifiers, and other micromanipulator probes and attachments. The construction of the microscope is simple and, therefore, since it is relatively inexpensive, the microscope may be easily upgraded in many ways for special purposes, including special optical effects. Finally, although the instrument was developed for patch-clamp and classical electrophysiological studies, it may be used in other types of investigations where freedom of microtool movement is imperative, such as in microsurgery applications.