The Role of Serine/Threonine and Tyrosine Protein Phosphatases in Common Snail Command Neurons in a Cellular Analog of Habituation

摘要

The effects of inhibitors of a series of serine-threonine phosphatases, i.e., okadaic acid (which suppresses PP1 and PP2A phosphatase activities), endothall (PP2A), cyclosporin A and cypermethrin (PP2B), CCT007093 (PPM1D), and dephostatin (blocks tyrosine phosphatases), on the depression and spontaneous recovery of the ACh-induced influx current in defensive behavior command neurons in the common snail were studied in a cellular analog of habituation. All the inhibitors used here altered the dynamics of depression of the current, while endothall also slowed spontaneous recovery of the ACh current. The results obtained here provide evidence of the relationship between changes in defensive behavior command neuron membrane cholinosensitivity in the common snail in a cellular analog of habituation on the one hand and the activities of all the protein phosphatases studied on the other. Application of a mathematical model addressing the possibility that receptors have different cellular locations suggested that these phosphatases are involved in the mobility (endocytosis and exocytosis) of the membrane cholinoreceptors responsible for changes in the ACh current in the cellular analog of habituation. Comparison of the experimental data and simulation-derived calculated curves of changes in the ACh current showed that the main target of protein phosphatases is the neuron’s transport system, i.e., the cytoskeleton and motor proteins.