Plateau potentials, caused by persistent inward currents (PICs), are a type of electrical behavior seen in neurons.
Metabotropic neurotransmitters, via monoaminergic input such as 5-HT and norepinephrine, modulate the activity of dendritic L-type Calcium channels that allow a sustained, positive, inward current into the cell.
The PICs can be turned off via the activation of high-frequency inhibitory input at which point the cell returns to a resting state.
[1] Periglomerular cells, inhibitory interneurons that surround and innervate olfactory glomeruli, have also been shown to exhibit plateau potentials.
Using iontophoretic, or two-photon glutamate uncaging experiments, it has been discovered that these plateau potentials include activities of voltage dependent calcium channels and NMDA receptors.