Eigengenes were calculated using the WGCNA package

i/o function and the upregulation of RGS4 in LC neurons after chronic opiates administration could be a mechanism of m-opioid receptor desensitization. Therefore, LC represents a useful model system to study chronic actions of opiates in the nervous system. Our dual-labelling experiments showed that Tra2b is highly expressed in TH-positive cells of the LC, buy Neuromedin N adding support to our hypothesis that Tra2b could be involved in morphine-induced functional changes in LC noradrenergic neurons. To assess a potential role for Tra2b in long-term adaptations to morphine administration, we studied the changes in Tra2b protein levels after chronic morphine and naloxone-precipitated withdrawal in the LC. Tra2b immunereactivity was increased by chronic morphine, and rapidly returned to control levels 2 h after naloxone-precipitated withdrawal. The rapid decreases of Tra2b and RGS4 protein level after acute morphine and naloxone-induced withdrawal may due to protein degradation processes, which need further investigation. The results show highly dynamic changes in Tra2b expression in the LC, suggesting a potential role of Tra2b in adaptations to chronic morphine exposure. The molecular mechanisms by which morphine regulates Tra2b expression and function are unknown. In vivo, morphine as opiate drug acts primarily on the Gai/o protein coupled mopioid receptor. Activation of Gai/o protein by m-opioid receptor leads to several events, including inhibition of cAMP and reduced protein phosphorylation. On the other hand, chronic morphine-induced dependence is a result of adaptation in GPCR signaling in the brain, including super-activation of the cAMP system and changes in PKA and ERK phosphorylation. These events may affect the activity of SR protein phosphatases and/or kinases and provide possible mechanisms that help to explain how Tra2b activity is regulated by morphine. A recent research reported that a component of PKA-dependent signaling Tra2b Regulates the Expression of RGS4 Protein pathways, DARPP-32, competed with protein phosphatase 1 to bind to Tra2b and changed the usage of Tra2b dependent alternative exons. In addition, nuclear accumulation of DARPP-32 was promoted by drugs of abuse. Those evidences reveal the connection of cAMP-dependent signaling pathways emanating from the cell membrane with the regulation of nuclear RNA processing. Our results also showed that besides the LC, Tra2b is colocalized with RGS4 in other brain regions important for opioid actions, such as the PFC, NAc, VTA and PAG. In the central nervous system, the PFC, NAc and VTA belong to mesocorticolimbic dopamine system. It is known that opioids increase dopaminergic signaling, and the increased dopamine signaling underlies the rewarding effects of the opioids and contributes to drug-seeking behavior. The 23892571 PAG is involved in opioidinduced analgesic responses. Thus, further investigation is needed to fully explore the role of splicing factor 3630970 Tra2b in opioid actions in these regions. Moreover, it is worthy to notice that besides RGS4, several other genes show altered RNA processing during opioid actionrelated events. For example, the m-opioid receptor gene has 25 splice variants in mice, 8 splice variants in rats and 11 splice variants in humans. The existence of those variants greatly increases the functional diversity and complexity of the m-opioid receptor gene in agonist-induced G protein activation, adenylyl cyclase activity, receptor internalization and phosphorylation. Man