Expression Of NK-1 Receptor In Dorsal Root Ganglia Neuron Of Chronic Arsenism Rats

Objective:(substance P,SP) is a peptide neurotransmitter and feeling nervous transmission which exists central nervous system and peripheral nerous system extensively. It involved in neurogenic inflammation, nociceptive stimulus, immunoregulation, nociceptive transmission and analgesic effect. SP combines with the NK-1 receptor the strongest and play impotant role by NK-1 receptor mainly. To exploe the expression of Neurokinin-1 receptor in the dorsal root ganglion(DRG) of chronic arsenism and control group rats. Understanding nociceptive information transfer, regulation and odyno-saitivity of arsenic poisoning induces peripheral nerve damages as well as exploring the mechanism of nerve damages included by arsenic of its related mechanism.Methods:30 SD(weight:180-230g) rats were randomly divided into 2 groups (15 rats in each group): the control group and the arsenic poisoning group. The normal group drank tap water. The chronic arsenic poisoning group drank tap water containing 100 mg/L NaAsO2. All rats were killed after 3 months, observe Neurokinin-1 receptor expression in DRG was detected by real time PCR,RT-PCR,immunohitochemical method on frozen sections.Results:1. Relative expression of Neurokinin- 1 receptor (0.968±0.224,1.405±0.685) were detected in two groups respectivel by real time PCR in cell membrane of DRG. There were significant difference between normal group and chronic arsenic poisoning group(P<0.05).2. Total RNA was reversed to cDNA by RT-PCR, then the NK-1 receptor primers was amplified being based on cDNA. PCR products were apperanced 217bp DNA by 1% agarose gel electrophoresis. The result indicated gene sequences of PCR products match NK-1 receptor primers. The experiment demonstrated NK-1 receptor was amplified successfully.3. Neurokinin-1 receptor were distributed widely in DRG cell membrane by immunohistochemisty technology. The expression is buff and buffy on cell membrane.Compared with its masc rate (67.23%±6.31%,96.66%±0.96%) and demi- quantitation optical density mean (0.118±0.012,0.153±0.018) in two groups respectively. There were significant difference between normal group and chronic arsenic poisoning group(P<0.05).Conclusions:The chronic arsenism is concomitant with the significant increase of Neurokinin-1 receptor expression in dorsal root.Neurokinin-1 receptor may be related to the transmisson of pain information and odyno-saitivity in arsenic poisoning induces nerve damages, expression. As a transmitter of sensory nerve, SP might play important roles in the process of nerve damages included by arsenic.