[Dose-response dependence of the excitatory effect of acetylcholine on Helix lucorum neurons after orthodromic tetanization].

Hill numbers before and after tetanic stimulation were calculated from dose-response dependence between the amplitude of the acetylcholine-induced inward current and the amplitude of the iontophoretic current through a micropipette filled with acetylcholine. Semi-intact Helix lucorum preparation was used. Acetylcholine-induced inward currents were recorded using two-electrode voltage clamp technique. Tetanic stimulation evoked changes in dose-response dependence but did not modify the slopes of dose-response plots (Hill numbers were 1.42 + 0.15 before and 1.41 + 0.15 after tetanization). It was concluded that increase in cholinosensitivity in LPa3 and RPa3 neurons after the orthodromic tetanic stimulation of nervus intestinalis is not accompanied by changes in the number of ligand-binding sites per acetylcholine receptor molecule or proportion of nicotinic and muscarinic cholinoreceptors.