Role of spinal p38α and β MAPK in inflammatory hyperalgesia and spinal COX-2 expression

Pharmacological studies indicate that spinal p38 mitogen-activated protein kinase plays a role in the development of hyperalgesia. We investigated whether either the spinal isoform p38 alpha or p38 beta is involved in peripheral inflammation evoked pain state and increased expression of spinal COX-2. Using intrathecal antisense oligonucleotides, we show that hyperalgesia is prevented by downregulation of p38 beta but not p38 alpha, whereas increases in spinal COX-2 protein expression at 8 hours are mediated by both p38 alpha and beta isoforms. These data suggest that early activation of spinal p38 beta isoform may affect acute facilitatory processing, and both p38 beta and a isoforms mediate temporally delayed upregulation of spinal COX-2. NeuroReport 21: 313317 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.