The Role of Myosins in Depression of Neuron Sensitivity to Acetylcholine in a Cellular Analog of Habituation in the Common Snail

The involvement of cytoskeletal motor proteins, i.e., myosins, in the molecular mechanism of depression of the acetylcholine sensitivity of defensive behavior command neurons was studied in the common snail. Thus, the effects of compounds impairing myosin functioning on ACh-evoked current depression curves in neurons were studied – the myosin light chain kinase blockers ML-7 and MLCK-IP-18, the non-muscle myosin II inhibitor blebbistatin, and the ROCK-I and ROCK-II kinase (which mainly activate non-muscle myosin II) inhibitor Y-27632. ML-7 and MLCK-IP-18 were found to weaken depression of the current, while blebbistatin and Y-27632 had no effect on depression. The experimental results and mathematical models of the effects of these blockers on the number of membrane-bound cholinoreceptors suggest the involvement of myosins (except non-muscle myosin II) in the endo- and exocytosis of cholinoreceptors and the resultant depression of the cholinosensitivity of the somatic membranes of neurons in a cellular analog of habituation. © 2014, Springer Science+Business Media New York.