[Determination of the Hill coefficient in the action of various agonists on the N-cholinoreceptors of the isolated mollusk neuron].

The Hill coefficient (2.07-2.23) of the response to low concentrations of acetylcholine and its analogues was unrelated to their cholinomimetic activity and molecular structure. A much greater value (2.32) was found for the acetylcholine analogue without the ester oxygen. Lesser values (1.96 and 1.81) were found for suberildicholine and succinylcholine. These values seem to be underestimated as even their subthreshold concentrations were not low sufficiently to estimate the true value of their Hill coefficient. More than two agonist molecules seem to be necessary for the opening of the snail acetylcholine receptor channel.