The present study examined the levels of NMDA receptor NR2 subunit tyrosine phosphorylation in a rat model of inflammation and correlated it with the development of inflammation and hyperalgesia. Hindpaw inflammation and hyperalgesia were induced by intraplantar injection of complete Freund's adjuvant. Proteins from the spinal cord (L4-L5) were immunoprecipitated with anti-NR2A or anti-NR2B antibodies and used for subsequent analysis using 4G-10, a specific anti-phosphotyrosine antibody. Compared with naive rats, there was a rapid and prolonged increase in tyrosine phosphorylation of the NR2B, but not NR2A, subunit after inflammation. The increase in NR2B tyrosine phosphorylation was dependent on primary afferent drive because (1) the phosphorylation correlated with the temporal profile of inflammation and hyperalgesia, (2) shorter-duration noxious stimulation produced a rapid and shorter-lasting increase in phosphorylation, and (3) local anesthetic block of the injected paw reversibly blocked inflammation-induced NR2B tyrosine phosphorylation and delayed hyperalgesia. The increase in NR2B tyrosine phosphorylation was abolished by intrathecal pretreatment with genistein, a tyrosine kinase inhibitor; PP2, an Src family tyrosine kinase inhibitor; AIDA, a group I metabotropic glutamate receptor antagonist; L733,060, an NK1 tachykinin receptor antagonist, and chelerythrine, a protein kinase C inhibitor. In addition, intrathecal PP2 delayed the onset of mechanical hyperalgesia and allodynia. These findings correlate in vivo NMDA receptor tyrosine phosphorylation with the development and maintenance of inflammatory hyperalgesia and suggest that signal transduction upstream to NR2B tyrosine phosphorylation involves G-protein-coupled receptors and PKC and Src family protein tyrosine kinases.

Hindpaw inflammation induces tyrosine phosphorylation (tyr-P) of the NMDA receptor (NMDAR) 2B (NR2B) subunit in the rat spinal dorsal horn that is closely related to the initiation and development of hyperalgesia. Here, we show that in rats with Freund's adjuvantinduced inflammation, the increased dorsal horn NR2B tyr-P is blocked by group I metabotropic glutamate receptor (mGluR) antagonists

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Escherichia albertii is a recently recognized close relative of Escherichia coli. This emerging enteropathogen possesses a type III secretion system (T3SS) encoded by the locus of enterocyte effacement, similar to enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC). Shiga toxin-producing strains have also been identified. The genomic features of E. albertii, particularly differences from other Escherichia species, have not yet been well clarified. Here, we sequenced the genome of 29 E. albertii strains (3 complete and 26 draft sequences) isolated from multiple sources and performed intraspecies and intragenus genomic comparisons. The sizes of the E. albertii genomes range from 4.5 to 5.1 Mb, smaller than those of E. coli strains. Intraspecies genomic comparisons identified five phylogroups of E. albertii. Intragenus genomic comparison revealed that the possible core genome of E. albertii comprises 3,250 genes, whereas that of the genus Escherichia comprises 1,345 genes. Our analysis further revealed several unique or notable genetic features of E. albertii, including those responsible for known biochemical features and virulence factors and a possibly active second T3SS known as ETT2 (E. coli T3SS 2) that is inactivated in E. coli. Although this organism has been observed to be nonmotile in vitro, genes for flagellar biosynthesis are fully conserved; chemotaxis-related genes have been selectively deleted. Based on these results, we have developed a nested polymerase chain reaction system to directly detect E. albertii. Our data define the genomic features of E. albertii and provide a valuable basis for future studies of this important emerging enteropathogen.