It seems necessary to characterize electrophysiological properties of human nicotinic acetylcholine receptors (nAChR) to obtain reference values for the study of diseased muscles. We therefore investigated nAChRs in aneurally grown human myotubes using the patch-clamp technique. Pulses of acetylcholine (ACh) were applied to outside-out patches with a fast application system. The peak and the rise time of the current elicited by pulses of various concentrations of ACh were evaluated. The results were interpreted using the circular reaction scheme developed recently for the nAChR of embryonic mouse muscle. In addition, the burst duration and the slope conductance of the ACh activated channel were evaluated.