A new multiple-drug applicator with minimal drug cross-talk, leakage, and consumption.

The relative effects of multiple drugs give an important clue to dissect a neuronal mechanism and to seek for a candidate neurotherapeutical agent. Here we have devised a "flute" applicator which can deliver several drugs to a neural cell preparation. The applicator stands by, cleaning itself with bath perfusate and delivers drugs only during test applications. This minimizes drug cross-talk in and leakage from the applicator and drug consumption. Using the applicator, we successfully compared the relative effects of widely different doses of an agonist in single neurons. The flute applicator would be a useful tool for pharmacological analyses.