Versatile temperature controlled tissue bath for studies of isolated cells using an inverted microscope.

The design of a small, inexpensive temperature controlled bath (0.25 ml volume) for electrophysiological studies of isolated cells is described. The design creates a uniform temperature (+/- 1 degree C) from ambient temperature to approximately 37 degrees C over a bath chamber area of 0.6 X 1 cm for flow rates from zero to 2 ml/min. Access for microelectrodes and unobstructed preparation viewing with an inverted microscope is afforded by a finely stranded heater sandwiched between two glass cover slips and located beneath the bath chamber. Battery operation of the feedback temperature controller and solution pre-heater minimizes electrical interference.