Ionic mechanisms evoked by acetylcholine-, nicotine-, and muscarine-induced depolarization of Helix lucorum RPa4 neurons

Three cholinomimetics: acetylcholine, nicotine and muscarine were applied locally on soma of Helix lucorum RPa4 neuron to study ionic nature of its depolarization. Substances that inhibit Na-, K-, Ca- and Cl-conductances were used. Acetylcholine increased Na-, Ca- and Cl-conductances. As the chlorine response part was small due to the proximity of the resting membrane potential and chlorine equilibrium potential, it may be concluded that the dominating response to acetylcholine is connected with the chemocontrolled input of Na+ and Ca2+ ions into a cell. Nicotine induced mainly Na-conductance and muscarine induced Ca-conductance.