Plateau potentials

Plateau potentials, caused by persistent inward currents (PICs), are a type of electrical behavior seen in neurons.

Spinal Cord

Plateau potentials are of particular importance to spinal cord motor systems.[1] PICs are set up by the influence of descending monoaminergic reticulospinal pathways. 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. This leads to a lasting depolarisation. In this state, the cell fires action potentials independent of synaptic input. 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]

Olfactory Bulb

Periglomerular cells, inhibitory interneurons that surround and innervate olfactory glomeruli, have also been shown to exhibit plateau potentials.[2][3]

Cortex and Hippocampus

Plateau potentials are also seen in the cortical,[4][5] and hippocampal pyramidal[6] neurons. 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.

References
  1. Svirskis, G; Gutman, A; Hounsgaard, J (January 2001). "Electrotonic structure of motoneurons in the spinal cord of the turtle: inferences for the mechanisms of bistability". Journal of Neurophysiology. 85 (1): 391–8. doi:10.1152/jn.2001.85.1.391. PMID 11152739.
  2. Masurkar, AV; Chen, WR (29 September 2011). "Potassium currents of olfactory bulb juxtaglomerular cells: characterization, simulation, and implications for plateau potential firing". Neuroscience. 192: 247–62. doi:10.1016/j.neuroscience.2011.06.012. PMC 3170655. PMID 21704678.
  3. Zhou, Z; Xiong, W; Masurkar, AV; Chen, WR; Shepherd, GM (November 2006). "Dendritic calcium plateau potentials modulate input-output properties of juxtaglomerular cells in the rat olfactory bulb". Journal of Neurophysiology. 96 (5): 2354–63. doi:10.1152/jn.00003.2006. PMID 16855116.
  4. Major, G; Polsky, A; Denk, W; Schiller, J; Tank, DW (May 2008). "Spatiotemporally graded NMDA spike/plateau potentials in basal dendrites of neocortical pyramidal neurons". Journal of Neurophysiology. 99 (5): 2584–601. doi:10.1152/jn.00011.2008. hdl:11858/00-001M-0000-002C-07A3-4. PMID 18337370.
  5. Milojkovic, BA; Radojicic, MS; Antic, SD (13 April 2005). "A strict correlation between dendritic and somatic plateau depolarizations in the rat prefrontal cortex pyramidal neurons". The Journal of Neuroscience. 25 (15): 3940–51. doi:10.1523/JNEUROSCI.5314-04.2005. PMC 5643048. PMID 15829646.
  6. Suzuki, T; Kodama, S; Hoshino, C; Izumi, T; Miyakawa, H (August 2008). "A plateau potential mediated by the activation of extrasynaptic NMDA receptors in rat hippocampal CA1 pyramidal neurons". The European Journal of Neuroscience. 28 (3): 521–34. doi:10.1111/j.1460-9568.2008.06324.x. PMID 18702724.
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