Glial activation in the periaqueductal gray promotes descending facilitation of XXXX through the @entity12220 MAPK signaling pathway.

@entity1441 @entity128 @entity158 @entity35 @entity12220 @entity8638 @entity1118 @entity9
UNASSIGNED: The midbrain ventrolateral periaqueductal gray (VL-PAG) is a key component that mediates @entity158 modulation. Although spinal cord glial cells appear to play an important role in @entity1118 development, the precise mechanisms involving descending facilitation pathways from the PAG following @entity128 are poorly understood. This study shows that cellular events that occur during glial activation in the VL-PAG may promote descending facilitation from the PAG during @entity9 . @entity8638 ( @entity8638 ) was induced by ligature construction of the sciatic nerve in male @entity35 . Behavioral responses to noxious mechanical (paw withdrawal threshold; PWT) and thermal (paw withdrawal latency; PWL) stimuli were evaluated. After @entity8638 , immunohistochemical and Western blot analysis of microglia and astrocytes in the VL-PAG showed morphological and quantitative changes indicative of activation in microglia and astrocytes. Intra-VL-PAG injection of microglial or astrocytic inhibitors attenuated PWT and PWL at days 7 and 14, respectively, following @entity8638 . We also evaluated the effects of intra-VL-PAG administration of the phosphorylated @entity12220 (p- @entity12220 MAPK) inhibitor @entity1441 at day 7 after @entity8638 . This treatment abolished microglial activation and produced a significant time-dependent attenuation of PWT and PWL. Western blot analysis showed localized expression of p- @entity12220 in the VL-PAG after @entity8638 . P- @entity12220 was expressed in labeled microglia of the VL-PAG but was not present in astrocytes and neurons on day 7 after @entity8638 . These results demonstrate that @entity8638 -induced @entity9 is associated with glial activation in the VL-PAG, which likely participates in descending @entity158 facilitation through the @entity12220 MAPK signaling pathway.    2015 Wiley Periodicals, Inc.
