Despite much research, the precise mechanism of gating during the activation of muscle nicotinic acetylcholine receptors is not fully understood. Here we explore the gating mechanism of unliganded nicotinic receptor with a mutation αL251T in its pore lining domain. At this position, a conserved ring of hydrophobic leucine residues narrows the channel lumen when in the closed conformation. Previous studies of mutations in this region have shown them to increase agonist EC50 and spontaneous channel activity. We recorded spontaneous single-channel currents in the cell-attached configuration from HEK293 cells transfected with human nicotinic ACh receptors (αβδε, transfection ratio 2:1:1:1) with a L251T mutation in the α subunit. Openings were detected and idealised using time-course fitting (program SCAN; http://www.ucl.ac.uk/Pharmacology/dc.html) and apparent open period and shut time distributions were plotted. In the absence of any agonist, two types of activations were seen: (1) brief single openings and (2) bursts of longer openings separated by short shut times. The distributions of apparent shut and open times showed two and three obvious components, respectively. The shortest shut (τ 17±2 µs; n=7 patches) and longest open (τ 2.6±0.6 ms) components were highly variable in area and virtually absent in some recordings. These two components correspond to the open and shut time intervals within bursts. The two shorter components in the open time distribution (τ 30±6 µs and 170±30 µs) arise from single openings and this finding suggest that there may be two different populations of spontaneous single openings. The presence of three components in the open time distribution of spontaneous activity clearly shows that unliganded gating is not a simple process and can’t be described with a simple closed-open transition scheme.