An in vitro method for recording the electrical activity of the isolated heart of the adult Drosophila melanogaster

A recording chamber for monitoring the electrophysiological properties of t he isolated heart of adult Drosophila melanogaster has been developed. Spon taneously generated field potentials of constant amplitude can be recorded for 6-8 h (n = 14); in very few cases. records were maintained stable for o ver 10 h (n = 4), and in some cases below 6 h (n = 5). The chamber consists of the tip of a micropipette. which allows for monitoring the field potent ial generated by the spontaneously contracting heart. The method can produc e accurate information about the heart rate and the amplitude of the cardia c action potential. The preparation can be used for pharmacological studies on the heart of D. melanogaster since it responds, with an increase in the heart rate, to unusually low concentrations of octopamine, 1 nM, a compoun d with cardioaccelerating properties for insect heart. The recording system can be easily modified for experiments on the heart of other insects. Fina lly. the isolated heart of D. melanogaster provides a simple method for ide ntifying mutations that affect heart physiology.