investigators have reported that mice lacking a functional immune capacity fail to resolve CDI in the absence of therapeutic intervention . Nevertheless, in concert with therapies designed to eradicate C. difficile, agents that selectively target intestinal P2Y6 signaling may prove useful in the treatment of CDI, especially in severe cases that exhibit an exaggerated immune response. Waking experience, including both prolonged wakefulness and exposure to enriched environments, independently produce dramatic increases in both synaptic markers and structural morphology throughout the fly brain and these changes are reversed during sleep. A strategy that has been useful for identifying the molecular mechanisms by which waking experience can increase sleep has been to evaluate MedChemExpress 480-44-4 mutations that disrupt synaptic plasticity. For example, flies mutant for the adenylyl cyclase rutabaga, the clock gene period, the Drosophila homologue of Serum Response Factor, blistered, and Epidermal growth factor receptor, have deficits in plasticity and do not respond to enriched environments 22576162 with increases in sleep. Importantly, rescue of each of these genes within the Pigment Dispersing Factor -expressing ventral lateral neurons restores both plasticity and increased sleep following social enrichment. Similarly, over-expression of the fragile X mental retardation 1 gene, which promotes neural pruning, blocks increases in the number of dendritic spines. Interestingly, while genetic manipulations that disrupt the formation of synapses have been evaluated for their role in sleep regulation, it is currently unknown how genetic manipulations that drive synaptic plasticity influence sleep. Extracellular signal-regulated kinase is a key molecule for the regulation of synaptic plasticity and is conserved throughout phylogeny. In rodents, ERK phosphorylation is necessary for learning, including conditioned place preference, fear conditioning and spatial learning. The Drosophila, homologue of ERK, rolled, has been shown to regulate synaptic bouton number at the larval neural muscular junction and has recently been correlated with sleep time following rhomboid and Star mediated 
activation of the EGFR. Moreover, ERK has been shown to regulate cAMP response element binding protein , a transcription factor that couples synaptic activity to long-term changes in neuronal plasticity . We show sleep deprivation and social enrichment independently increase ERK phosphorylation in wild-type flies. We also report that expressing an active version of ERK in the adult fly results in an increase in sleep and an increase in structural plasticity in the LNvs. Conversely, disrupting ERK reduces sleep and prevents both the behavioral and structural plasticity normally induced by social enrichment. Finally, using transgenic flies carrying a cAMP response 1 The Role of ERK in Sleep and Plasticity element -luciferase reporter we show that ERK activation enhances CRE-Luc activity while disrupting ERK reduces it. 11336787 These data suggest that phosphorylation of ERK may be a mechanism for regulating sleep and plasticity. socially-enriched sibling. The difference is referred to as Sleep. Immunohistochemistry For the sleep deprivation and social enrichment studies, all animals were sacrificed at ZT0 and immediately processed for either immunohistochemistry or western blotting. Brains were dissected in cold PBS and processed for standard wholemount immunostaining as described previously. The following