Neurochemical Changes Following Activation of the Dural Afferent

Abstract

The objective of the study was to explore the neurochemical effects of dural afferent activation in different regions of the brain, the ventral tegmental area (VTA) and the nucleus accumbens (NAcc), and determine how these mechanisms play a role in pain relief following onset of migraine pain. Inflammatory mediators (IM) or synthetic interstitial fluid (SIF) were injected into the dura of rats to initiate dural afferent activation, followed by treatments of saline (Sal) or lidocaine (Lido) injection into the rostral ventromedial medulla (RVM). Upon collection of VTA and NAcc tissue sections from each treatment group, cells were immunolabeled for FOS to determine action potential prevalence associated with dopamine release. VTA showed increased FOS expression in rats treated with IM + Sal, while NAcc showed greater expression in IM + Lido treatment group. These effects may be characteristic of the role of lidocaine within the reward system, although signaling within the dopaminergic system may be altered upon projection into the NAcc region. These findings are consistent with the possibility of outside factors of signal propagation throughout the dopaminergic system. Further research on the underlying mechanisms of the dopaminergic system may provide novel treatment strategies of migraine pain relief.