Ath and DeLeo, 2009). The Janus tyrosine kinase/signal transducer and activator of transcription pathway in astrocytes is also activated by opioid exposure in a CGRP- and MEKdependent fashion (Wang et al., 2010a). The common downstream signaling consequence of these MAPK and related pathways is activation of NF- B. Morphine causes activation of NF- B within CNS non-neuronal cells in a fashion that