Abstract
: The procedure for the determination of cholinesterase activity in μμl samples of cytoplasm and nucleoplasm of isolated nerve cells is described. The method is an application and modification of the Cartesian diver technique of Linderstrom‐Lang, which allows quantitative determinations in the order of 1× 108 μl CO2/hour with ± 15 % accuracy. By means of this method acetyl‐cholinesterase activity could be demonstrated in the cytoplasm and the nucleus of anterior horn cells of the spinal cord of the rat.