GABA pretreatment dose-dependently regulates the magnitude of the subsequent insulin inhibition – neuronal response magnitude analysis to microiontophoretic insulin as a function of GABA pretreatment ejection charge or insulin current intensity. A, Neuronal response magnitudes to insulin are significantly correlating with the GABA pretreatment ejection charge (148 insulin applications recorded from 29 neurons); B, Neuronal responses of 12 neurons with individual GABA-dose-dependence tests and their linear trendlines show the same correlation; C, Neuronal response magnitudes to insulin are not correlating with the current intensity of insulin application (148 insulin applications recorded from 29 neurons). Abbreviations: nC, nanoCoulombs; nA, nanoAmperes; s, seconds.