Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory p...Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory pain,but its role in morphine tolerance is unclear.In this study,we established rat and mouse models of morphine tolerance by intrathecal injection of morphine for 7 consecutive days.We found that morphine induced rat spinal cord neurons to release a large amount of HMGB1.HMGB1 regulated nuclear factor κB p65 phosphorylation and interleukin-1β production by increasing Toll-like receptor 4receptor expression in microglia,thereby inducing morphine tolerance.Glycyrrhizin,an HMGB1 inhibito r,markedly attenuated chronic morphine tole rance in the mouse model.Finally,compound C(adenosine 5’-monophosphate-activated protein kinase inhibitor) and zinc protoporphyrin(heme oxygenase-1 inhibitor)alleviated the morphine-induced release of HMGB1 and reduced nuclear factor κB p65 phosphorylation and interleukin-1β production in a mouse model of morphine tolerance and an SH-SY5Y cell model of morphine tole rance,and alleviated morphine tolerance in the mouse model.These findings suggest that morphine induces HMGB1 release via the adenosine 5’-monophosphate-activated protein kinase/heme oxygenase-1 signaling pathway,and that inhibiting this signaling pathway can effectively reduce morphine tole rance.展开更多
Aim To investigate the effects of iptakalim, a new structural potassium channel opener （KCO）, on intracellular calcium concentration ([Ca2+]i), protein kinase C （PKC）, and cAMP-dependent kinase （PKA） activities ...Aim To investigate the effects of iptakalim, a new structural potassium channel opener （KCO）, on intracellular calcium concentration ([Ca2+]i), protein kinase C （PKC）, and cAMP-dependent kinase （PKA） activities in rat tail artery smooth muscle cells （RTA-SMC）, and to analyze mechanisms involved in iptakalim reversing hypertensive vascular remodeling. Methods RTA-SMC was cultured and passages 3-4 were used for experiment. [Ca2+]i was measured by laser scanning confocal microscope after loaded with fluorescent indicator fluo-3-acetoxymethylester, and activities of PKA and PKC were detected by commercial assay kits （the nonradioactive PepTag system） following instructions. Results Compared with baseline, [Ca2+]i reduced significantly after iptakalim- or pinacidil-treatment at concentrations of 0.1, 1 and 10 (μmol·L-1), while diazoxide caused significant decrease at concentration of 1 and 10 (μmol·L-1). After preincubation with 1 (μmol·L-1) glibenclamide, [Ca2+]i was not significantly changed when iptakalim, pinacidil or diazoxide were added at concentration of 0.1 and 1 (μmol·L-1). Activities of PKA and PKC increased significantly by 1 μmol·L-1 iptakalim- or pinacidil-treatment, while 1 μmol·L-1 diazoxide induced significant change in activity of PKC but not in that of PKA. Conclusion The characteristics of iptakalim on [Ca2+]i, PKA and PKC are more or less similar to those of pinacidil. Iptakalim decreased [Ca2+]i while increased PKA and PKC activities of RTA-SMCs, which may contribute to its ability to reverse antihypertensive vascular remodeling.展开更多
基金supported by the National Natural Science Foundation of ChinaNos.81971047 (to WTL) and 82073910 (to XFW)+2 种基金the Natural Science Foundation of Jiangsu Province,No.BK20191253 (to XFW)Key R&D Program (Social Development) Project of Jiangsu Province,No.BE2019 732 (to WTL)Jiangsu Province Hospital (the First Affiliated Hospital of Nanjing Medical University) Clinical Capacity Enhancement Project,No.JSPH-511B2018-8 (to YBP)。
文摘Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory pain,but its role in morphine tolerance is unclear.In this study,we established rat and mouse models of morphine tolerance by intrathecal injection of morphine for 7 consecutive days.We found that morphine induced rat spinal cord neurons to release a large amount of HMGB1.HMGB1 regulated nuclear factor κB p65 phosphorylation and interleukin-1β production by increasing Toll-like receptor 4receptor expression in microglia,thereby inducing morphine tolerance.Glycyrrhizin,an HMGB1 inhibito r,markedly attenuated chronic morphine tole rance in the mouse model.Finally,compound C(adenosine 5’-monophosphate-activated protein kinase inhibitor) and zinc protoporphyrin(heme oxygenase-1 inhibitor)alleviated the morphine-induced release of HMGB1 and reduced nuclear factor κB p65 phosphorylation and interleukin-1β production in a mouse model of morphine tolerance and an SH-SY5Y cell model of morphine tole rance,and alleviated morphine tolerance in the mouse model.These findings suggest that morphine induces HMGB1 release via the adenosine 5’-monophosphate-activated protein kinase/heme oxygenase-1 signaling pathway,and that inhibiting this signaling pathway can effectively reduce morphine tole rance.
文摘Aim To investigate the effects of iptakalim, a new structural potassium channel opener （KCO）, on intracellular calcium concentration ([Ca2+]i), protein kinase C （PKC）, and cAMP-dependent kinase （PKA） activities in rat tail artery smooth muscle cells （RTA-SMC）, and to analyze mechanisms involved in iptakalim reversing hypertensive vascular remodeling. Methods RTA-SMC was cultured and passages 3-4 were used for experiment. [Ca2+]i was measured by laser scanning confocal microscope after loaded with fluorescent indicator fluo-3-acetoxymethylester, and activities of PKA and PKC were detected by commercial assay kits （the nonradioactive PepTag system） following instructions. Results Compared with baseline, [Ca2+]i reduced significantly after iptakalim- or pinacidil-treatment at concentrations of 0.1, 1 and 10 (μmol·L-1), while diazoxide caused significant decrease at concentration of 1 and 10 (μmol·L-1). After preincubation with 1 (μmol·L-1) glibenclamide, [Ca2+]i was not significantly changed when iptakalim, pinacidil or diazoxide were added at concentration of 0.1 and 1 (μmol·L-1). Activities of PKA and PKC increased significantly by 1 μmol·L-1 iptakalim- or pinacidil-treatment, while 1 μmol·L-1 diazoxide induced significant change in activity of PKC but not in that of PKA. Conclusion The characteristics of iptakalim on [Ca2+]i, PKA and PKC are more or less similar to those of pinacidil. Iptakalim decreased [Ca2+]i while increased PKA and PKC activities of RTA-SMCs, which may contribute to its ability to reverse antihypertensive vascular remodeling.
