Method for measuring the contractions of small hearts in organ culture

AUTHORS' SYNOPSIS: An instrument that was originally designed to detect microvibrations of aircraft wings has been adapted for use in measuring the amplitude, rate, and time-course of contraction of isolated foetal mouse hearts. The device is capacitance-sensitive and responds to small displacements of objects in its electrical field. The beating of a heart positioned near the probe produces such displacements. The effects of noradrenaline, acetylcholine, calcium, and temperature as detected by the probe are similar to their effects on cardiac muscle shortening as measured by conventional techniques. The method has the advantage of not requiring physical attachment of transducers directly to the tissue, which can seriously damage the contractile ability of small, fragile hearts.