Astroglial Amino Acid Shuttle Involved in Nociceptive Pain Sensitization!

"This study has demonstrated that the central sensitization induced in functionally identified nociceptive neurons in trigeminal subnucleus caudalis (the medullary dorsal horn) by application of an inflammatory irritant to the rat's tooth pulp can be significantly attenuated by continuous intrathecal superfusion of methionine sulfoximine, an inhibitor of the astroglial enzyme glutamine synthetase that is involved in the glutamate–glutamine shuttle......Further, the lack of any observed significant effects of MSO alone, in contrast to our findings that it significantly attenuates MO-induced central sensitization, suggests that its action on astroglial GS is not evident in basal conditions but is apparent in hyperexcitable states, consistent with findings by ourselves and others that glia may not affect basal nociceptive processing but rather participate in exaggerated pain states. It is also noteworthy that an excess of glutamine in the CNS is involved in ammonia neurotoxicity possibly through its detrimental effects on mitochondrial function."

CiteULike: Astroglial Glutamate Glutamine Shuttle Is Involved in Central Sensitization of Nociceptive Neurons in Rat Medullary Dorsal Horn: "Chiang, C.-Y., Wang, J., Xie, Y.-F., Zhang, S., Hu, J. W., Dostrovsky, J. O., and Sessle, B. J. (2007). Astroglial glutamate glutamine shuttle is involved in central sensitization of nociceptive neurons in rat medullary dorsal horn. J. Neurosci., 27(34):9068-9076."


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