AIM: To investigate EP4-selective agonist effect on indomethacin-induced gastric lesions and on the spontaneous healing of chronic gastric ulcers.METHODS: In a mouse model of gastric bleeding with high dose of indomet...AIM: To investigate EP4-selective agonist effect on indomethacin-induced gastric lesions and on the spontaneous healing of chronic gastric ulcers.METHODS: In a mouse model of gastric bleeding with high dose of indomethacin (20 mg/kg), an EP4-selective agonist was administered orally. Stomach lesions and gastric mucous regeneration were monitored. In a mouse model of chronic gastric ulcer induced by acetic acid, EP4 agonist effect on the healing of chronic gastric ulcer was evaluated in the presence or absence of low dose indomethacin (3 mg/kg). In cultured human gastric mucous cells, EP4 agonist effect on indomethacin-induced apoptosis was assessed by ? ow cytometry.RESULTS: The EP4-selective agonist reduced high dose indomethacin-induced acute hemorrhagic damage and promoted mucous epithelial regeneration. Low-dose indomethacin aggravated ulcer bleeding and inflammation, and delayed the healing of the established chronic gastric ulcer. The EP4 agonist, when applied locally, not only offset indomethacin-induced gastric bleeding and inflammation, but also accelerated ulcer healing. In the absence of indomethacin, the EP4 agonist even accelerated chronic gastric ulcer healing and suppressed inflammatory cell infiltration in the granulation tissue. In vitro, the EP4 agonist protected human gastric mucous cells from indomethacininduced apoptosis.CONCLUSION: EP4-selective agonist may prevent indomethacin-induced gastric lesions and promote healing of existing and indomethacin-aggravated gastric ulcers, via promoting proliferation and survival of mucous epithelial cells.展开更多
Objective The glial cells of the central nervous system are involved in tripartite signaling,therefore we have been investigating the relationship between sensory neurons and non-neuronal cells in isolated preparation...Objective The glial cells of the central nervous system are involved in tripartite signaling,therefore we have been investigating the relationship between sensory neurons and non-neuronal cells in isolated preparations of dorsal root ganglia(DRG).Methods The mixed cell cultures of dissociated DRG cells were separated to yield enriched fractions of IB4-positive cells(small diameter,non-peptidergic cells),IB4-negative cells(small diameter,peptidergic cells,and large diameter cells),and non-neuronal cells(principally satellite glial cells,Schwann cells and fibroblasts).Adenylyl cyclase activity was assayed by measuring production of [3H]cAMP from cells preloaded with [3H]adenine.Results PGE2 and the PGI2 mimetic cicaprost stimulated adenylyl cyclase activity which was inhibited by ONO-AE3-208(EP4 antagonist)or CAY10441(IP antagonist)with estimated pA2 values of 8.9 and 8.2,respectively.Surprisingly,both PGE2 and cicaprost-stimulated [3H] cAMP production was greatest in the non-neuronal cell preparation.Furthermore,when the number of non-neuronal cells was kept constant and the number of neuronal cells was increased,we observed a progressive decrease in prostanoid-stimulated activity.Conclusions Sensory neurons appear to regulate prostanoid receptor-mediated cell signaling in non-neuronal cells within the DRG.展开更多
文摘AIM: To investigate EP4-selective agonist effect on indomethacin-induced gastric lesions and on the spontaneous healing of chronic gastric ulcers.METHODS: In a mouse model of gastric bleeding with high dose of indomethacin (20 mg/kg), an EP4-selective agonist was administered orally. Stomach lesions and gastric mucous regeneration were monitored. In a mouse model of chronic gastric ulcer induced by acetic acid, EP4 agonist effect on the healing of chronic gastric ulcer was evaluated in the presence or absence of low dose indomethacin (3 mg/kg). In cultured human gastric mucous cells, EP4 agonist effect on indomethacin-induced apoptosis was assessed by ? ow cytometry.RESULTS: The EP4-selective agonist reduced high dose indomethacin-induced acute hemorrhagic damage and promoted mucous epithelial regeneration. Low-dose indomethacin aggravated ulcer bleeding and inflammation, and delayed the healing of the established chronic gastric ulcer. The EP4 agonist, when applied locally, not only offset indomethacin-induced gastric bleeding and inflammation, but also accelerated ulcer healing. In the absence of indomethacin, the EP4 agonist even accelerated chronic gastric ulcer healing and suppressed inflammatory cell infiltration in the granulation tissue. In vitro, the EP4 agonist protected human gastric mucous cells from indomethacininduced apoptosis.CONCLUSION: EP4-selective agonist may prevent indomethacin-induced gastric lesions and promote healing of existing and indomethacin-aggravated gastric ulcers, via promoting proliferation and survival of mucous epithelial cells.
文摘Objective The glial cells of the central nervous system are involved in tripartite signaling,therefore we have been investigating the relationship between sensory neurons and non-neuronal cells in isolated preparations of dorsal root ganglia(DRG).Methods The mixed cell cultures of dissociated DRG cells were separated to yield enriched fractions of IB4-positive cells(small diameter,non-peptidergic cells),IB4-negative cells(small diameter,peptidergic cells,and large diameter cells),and non-neuronal cells(principally satellite glial cells,Schwann cells and fibroblasts).Adenylyl cyclase activity was assayed by measuring production of [3H]cAMP from cells preloaded with [3H]adenine.Results PGE2 and the PGI2 mimetic cicaprost stimulated adenylyl cyclase activity which was inhibited by ONO-AE3-208(EP4 antagonist)or CAY10441(IP antagonist)with estimated pA2 values of 8.9 and 8.2,respectively.Surprisingly,both PGE2 and cicaprost-stimulated [3H] cAMP production was greatest in the non-neuronal cell preparation.Furthermore,when the number of non-neuronal cells was kept constant and the number of neuronal cells was increased,we observed a progressive decrease in prostanoid-stimulated activity.Conclusions Sensory neurons appear to regulate prostanoid receptor-mediated cell signaling in non-neuronal cells within the DRG.
