ABSTRACT
Objective To study the effect of APETx2 on the expression of ASIC3 APETx2 in a rat model of acute gastric mucosal lesion(AGML). Methods Twenty-four Wistar rats were randomly assigned to three groups in equal number : normal control group, water immersion restraint stress (WIRS) group, APETx2 treatment group. AGML was induced by WIRS for 6 hours, and APETx2 (25 μg/kg) was injected intraperitoneally before the onset of stress. Intragastric pH and gastric histopathological changes were measured and the expression of ASIC3 mRNA in DRG neurons projecting to rat stomach was examined by real-time PCR. Immunohistochemistry was performed to detect the localization of ASIC3. Results Compared with the normal control group, the WIRS group showed obvious gastric injury with lower values of intragastric pH and extensive expression of ASIC3 in the DRG neurons (P < 0.05). The treatment with APETx2 before the onset of WIRS significantly alleviated the gastric mucosal injury, decreased gastric acidity and reduced ASIC3 expression in DRG neurons (P < 0.05). Conclusions ASIC3 expression in DRG neurons projecting to rat stomach is strongly associated with gastric mucosal lesion and acidosis in the WIRS model. APETx2 can improve gastric acidosis and prevent the occurrence of these lesions.
ABSTRACT
Metabotropie glutamate receptor (mGluR) 2/3 plays an important role on the nociceptive transmission from periphery to spinal cord.The previous studies demonstrated that mGluR2 can contribute to mechanical hypersensitivity and thermal hypersensitivity in rat.Therefore,in the present study,by using the immunofluorescenee histochemical technique,we try to explore that whether mGluR2 is colocalized with acid-sensing ion channel 3 (ASIC3),a muhi-modulator of mechanosensation,or transient receptor potential/vanilloid receptor subtype-1 (TRPV1),which responses for thermosensation in dorsal root ganglion (DRG).Morphological observations showed that mGluR2-immunoreactivity was mainly distributed in cellular plasma of neurons in DRG.The counting number results indicated that 35.84% of DRG neurons were mGluR2-immunoreactive (ir).On the other hand,82.61% of mGluR2-ir cells were the small-diameter neurons (diameter:＜30 μm),5.79% of which were the medium-diameter neurons (diameter:30-50μm) and 11.59% of which was the large-diameter neurons (diameter:＞50 tun).Furthermore,42.45% and 79.78% of mGiuR2-ir cells was individually co-localized with ASIC3-or TRPVI-ir in small-diameter neurons in the double-labeled immunofluorescence sections.The present results suggest that mGhiR2 mainly exists in small neurons of the DRG,which are regarded as nociceptors consisting of AS-and C-fibers.While mGluR2 is highly co-localized with ASIC3 and TRPV1,implying their potential relationship in DRG may be involved in mechanical hypersensitivity and thermal hypersensitivity.