It has been reported that the small type of neurons in the dorsal root ganglion (DRG) play an important role in pain regulation by a presynaptic mechanism via the metabotropic type-B γ-aminobutyric acid receptors ( GABABR ). In order to understand whether the 2populations of the small type of the neurons, peptidergic and nonpeptidergic, in DRG share the same role, immunoflourescent histochemical methods and confocal laser scanning microscope were employed to investigate the expression of the GABABR in the peptidergic and nonpeptidergic small DRG neurons. The results revealed that 92% of the peptidergic and 90% of nonpeptidergic small DRG neurons express GABABR in their perikarya and central processes, which distribute in the various laminae of the spinal dorsal horn. These results suggest both the peptidergic and nonpeptidergic populations of the small neurons in the DRG share similar role in pain modulation via presynaptic mechanisms but in given laminae of the spinal dorsal horn.

This study aims to reveal the pharmacokinetics of Shuganning Injection in normal rats. In this experiment,ultra-high performance liquid chromatography-electrospray-tandem mass spectrometry( UPLC-ESI-MS/MS) was used to establish an analytical method for simultaneous determination of chlorogenic acid,gardenioside,oroxylin A and baicalin in rat plasma. Then,the non-compartmental model( NCA) in Phoenix WinN onL in 6. 4 software was used to fit pharmacokinetic parameters. The methodological validation showed that the linear relationship of the components in rat plasma samples were good( r>0. 995). The recovery rate and matrix effect of plasma samples with low,middle and high concentration were 79. 14%-101. 4%. The intra-day and inter-day precision,accuracy and stability meet the requirements of biological sample analysis. The half-life( t1/2) of chlorogenic acid,gardenioside,oroxylin A did not change significantly and the area under blood concentration-time curve( AUC0-t) is proportional to the dose,which suggested that three components showed a linear kinetic characteristics,but baicalin showed nonlinear kinetic characteristics. Moreover,the retention time of each component in rats was short. The established UPLC-MS/MS quantitative analysis method is rapid,sensitive and accurate,which can be used for the determination of chlorogenic acid,gardenioside,oroxylin A and baicalin in rat plasma and pharmacokinetic study of Shuganning Injection.
Animals ; Chlorogenic Acid ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Plasma ; Rats ; Rats, Sprague-Dawley ; Reproducibility of Results ; Tandem Mass Spectrometry