ABSTRACT
Pain is often debilitating, and current treatments are neither universally efficacious nor without risks. Transient receptor potential (TRP) ion channels offer alternative targets for pain relief, but little is known about the regulation or identities of endogenous TRP ligands that affect inflammation and pain. Here, transcriptomic and targeted lipidomic analysis of damaged tissue from the mouse spinal nerve ligation (SNL)-induced chronic pain model revealed a time-dependent increase in Cyp1b1 mRNA and a concurrent accumulation of 8,9-epoxyeicosatrienoic acid (EET) and 19,20-EpDPA post injury. Production of 8,9-EET and 19,20-EpDPA by human/mouse CYP1B1 was confirmed in vitro, and 8,9-EET and 19,20-EpDPA selectively and dose-dependently sensitized and activated TRPA1 in overexpressing HEK-293 cells and Trpa1-expressing/AITC-responsive cultured mouse peptidergic dorsal root ganglia (DRG) neurons. TRPA1 activation by 8,9-EET and 19,20-EpDPA was attenuated by the antagonist A967079, and mouse TRPA1 was more responsive to 8,9-EET and 19,20-EpDPA than human TRPA1. This latter effect mapped to residues Y933, G939, and S921 of TRPA1. Intra-plantar injection of 19,20-EpDPA induced acute mechanical, but not thermal hypersensitivity in mice, which was also blocked by A967079. Similarly, Cyp1b1-knockout mice displayed a reduced chronic pain phenotype following SNL injury. These data suggest that manipulation of the CYP1B1-oxylipin-TRPA1 axis might have therapeutic benefit.
ABSTRACT
@#Genotoxic or potentially genotoxic impurities seriously threaten people′s health, therefore, it is necessary to identify and quantify these impurities in pharmaceutical materials even at trace levels. Due to the special requirements on the sensitivity, selectivity, analyte stability and matrix effect, development of analytical methods is a challenge for the determination of genotoxic impurities. This paper reviews the recent advances in analytical methods for trace levels of commonly encountered genotoxic or potentially genotoxic impurities, including alkyl halides, alkyl sulfonates, hydrazines, epoxides and acyl halides, which would be helpful to control these impurities.
ABSTRACT
The epoxides undergo smoothly ring-opening reaction with various amines catalyzed by zinc perchlorate on alumina under mild reaction conditions. All the reactions were carried out at room temperature to afford the corresponding b-amino alcohols in excellent yields. The catalyst was recovered and reused further reactions with very good efficiency.
ABSTRACT
Epoxides undergo rapidly ring-opening reaction with various amine nucleophiles in the presence of Europium triflate. The catalyst was very active and used in 10% mole only. All the reactions were carried out at room temperature in methylene dichloride to afford the corresponding b-amino alcohols in very good yields.