This work is a first attempt to investigate the effects of ultra wideband (UWB) electromagnetic pulses upon a reaction of biological interest involved in neuronal communication, the hydrolysis of acetylcholine chloride (AChCl) catalyzed by the acetylcholine esterase enzyme (AChE). This study is based on broadband impedance measurements performed with the same cell in the range 40 Hz-4 GHz within 10s, without or with superimposed nanopulses, as a function of the elapsed time. The response above 1 MHz was assigned to the conductive and dielectric properties of the aqueous solution containing AChCl and AChE filling the cell. The response below 100 kHz was due to electrode impedance at the golden cell wall/solution interfaces. This low frequency behavior was ascribed to a dynamical adsorption-desorption process of AChCl in equilibrium with the bulk. The electrode impedance behaves as a sensor of the actual bulk concentration of AChCl when the reaction is in progress. From impedance spectra analysis it was shown that superimposed nanopulses slowed down the hydrolysis reaction, the stronger this effect the higher the pulse repetition rate. The inhibition of the reaction could be related to a lesser catalytic activity of AChE possibly through a conformational change induced by nanopulses. (C) 2014 The Electrochemical Society. All rights reserved.