Endogenous 5-HT In Plasma And Serum Of Early SHR Rat & Method For Endogenous Saccharides In Rat Urine

Serotonin(5-HT)is an important endogenous monoamine neurotransmitter,playing an essential role in neural communication in mammalians.Dysregulation of 5-HT was frequently reported in the studies of many diseases including colon cancer and psychiatric disorders.We developed a simple,fast and sensitive method to determine the 5-HT in the serum or plasma of rats.The results indicated that 5 times volume of cold organic solvents(methanol/acetonitrile,v/v,50/50)coupled with vortex for 1 min and incubated at-20?C for 20 min were the most optimal conditions for extraction.The results,according to the linearity,precision,recovery,matrix effect and stability,showed that the method was satisfactory in the quantification of endogenous 5-HT in the serum or plasma of rats.5-HT was also reported to be involved in the forming and development of hypertension.In the past decades,5-HT was frequently reported to be elevated in the plasma of hypertension patients or hypertension models,which led to the main-stream idea of being constrictor of the elevated 5-HT.Yet,recent studies showed that 5-HT acts as both a dilator and constrictor of the arterial circulation.Therefore,we explored the 5-HT regulation in the serum and plasma of early Spontaneous Hypertension Rats(SHRs)of 11-week-old,compared to those of normal SD rats,using the hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.Interestingly,the results showed that the 5-HT in the serum of SHR was significantly different from that in the normal SD rats,with a significant down-regulation.In addition,the 5-HT in the plasma of SHR did not show any significantly difference from that in the normal SD rats.It seems that the result of unregulated free 5-HT in the plasma and the decreased 5-HT in the serum of early SHRs supports that elevated free 5-HT is not the forming factor for the hypertension.It also seems the 5-HT in the serum is possible to be influential in directing the hypertension statement,to the 11-week-old SHR rats in our study.To explore the metabolism of endogenous saccharides in rat,we developed a simple,fast,simultaneously quantitative method for the endogenous saccharides in rat urine,using the hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.In order to quantify 15 endogenous saccharides in rat urine,various conditions,including columns,chromatographic conditions,MS conditions,and urine preparation methods,were investigated and optimized.The reproducibility,precision,recovery,and stability of the method were verified.The results indicated that 5 times volume of cold organic solvents(methanol/acetonitrile,v/v,50/50)coupled with vortex for 1 min and incubated at-20?C for 20 min were the most optimal conditions for extraction.The results,according to the linearity,precision,recovery,matrix effect and stability,showed that the method was satisfactory in the quantification of endogenous saccharides in rat urine.Meeting the requirement of quantification in specific expanded metabolomic studies,the quantified analysis of endogenous saccharides in rat urine performed excellently in the sensitivity,high throughput and simple sample preparation.