A microscopic setup for combined, and time‐coordinated electrophysiological and confocal fluorescence microscopic experiments on neurons in living brain slices

In this paper, a microscopic system for cell physiological research is presented. The setup which is to a large extent based on commercially available products was designed to establish a platform for time‐coordinated electrophysiological and fluorescence optical compound experiments on living neurons in brain slices. Instruments for infrared differential interference contrast video microscopy (IRDICM), confocal scanning laser microscopy (CSLM), and for patch clamp studies have been assembled into one unit. Using the IRDICM equipment, a neuron can be patched somatically and dendritically. Loading the neuron with a Ca2+ indicating dye substance can be examined epifluorescence optically using the Hg lamp or Xe lamp of the microscope. A stimulus initiating the propagation of an action potential through a dendrite can be synchronized to the electronic control unit of the CSLM, and changes in the concentration of Ca2+ in the dendrite can be recorded in a time‐coordinated way. The setup has been used successfully in order to study in vitro the dynamics of intracellular Ca2+ in the dendritic system of living neurons in brain slices