Carbon monoxide (CO) has recently proven to be an important bioactive or signaling molecule in mammalian cells. Its effects are mainly mediated by nitric oxide (NO) and cyclic GMP (cGMP). In Vicia faba leaves, CO prod...Carbon monoxide (CO) has recently proven to be an important bioactive or signaling molecule in mammalian cells. Its effects are mainly mediated by nitric oxide (NO) and cyclic GMP (cGMP). In Vicia faba leaves, CO production and heme oxygenase (HO) activity, an important CO synthetic enzyme, are first reported to increase in response to ABA treatment, which could result in stomatal closure. Inter- estingly, ABA-induced stomatal closure in V. faba guard cells is partially blocked when the synthetic CO inhibitor ZnPP, or the CO/NO scavenger Hb is added. Furthermore, we show that, exogenously applied CO donor, hematin, and CO aqueous solution not only result in the enhancement of CO release, but also time-dependently induce stomatal closure, and the latter is mimicked by the application of an NO donor SNP. The above-mentioned stomatal closure effects are differentially reversed by the addition of tungstate, a potent inhibitor of NO synthetic enzyme nitrate reductase (NR), the specific NO scavenger cPTIO, ZnPP, or Hb. During treatment for 4 h, SNP, 0.01% CO aqueous solution or hematin significantly triggers NO synthesis, whereas cPTIO, or tungstate approximately fully inhibits NO fluorescence. Ad- ditionally, application of the GC inhibitor ODQ blocks CO-induced stomatal closure. This inhibition could be reversed when 8-Br-cGMP is added. Thus, the above results suggest that CO produced by HO is involved in ABA-induced stomatal closure, and NO and cGMP may function as downstream interme- diates in the CO signaling responsible for stomatal closure.展开更多
Background The form deprivation （FD） reduces spatial contrasts and induces myopia. Nitric oxide and cyclic guanosine monophosphate （cGMP） are involved in visual signal transmission. This study investigated changes...Background The form deprivation （FD） reduces spatial contrasts and induces myopia. Nitric oxide and cyclic guanosine monophosphate （cGMP） are involved in visual signal transmission. This study investigated changes in nitric oxide synthase （NOS） activity and cGMP concentration in ocular tissues in acute and chronic form deprivation myopia. Methods Guinea pigs had one eye covered by translucent glass for 7, 14 or 21 days. Untreated litter mates were used as controls. NOS activity and cGMP concentrations in the retinal, choroidal and scleral tissues of FD eyes and control eyes were analyzed by radioimmunoassay after various durations of FD. The expression of NOS subtypes was identified by immunohistochemistry. Results Myopia was successfully induced in FD eyes after 14 days. Compared with control groups, the retinal NOS activity and cGMP concentrations in the FD eyes significantly increased after 14 and 21 days while the retinal NOS activity in the FD eyes was transiently suppressed by 7 days of FD. The NOS activity and cGMP concentrations of choroid and sclera in the FD eyes were higher than in the control groups at 21 days. The three isoenzymes of nitric oxide synthase were detected in the ocular tissues of guinea pigs. Conclusions The NOS activity and cGMP concentrations were upregulated after chronic FD and the retinal NOS activity was transiently suppressed at acute FD. The function of elevated NOS activity may be mediated by cGMP.展开更多
目的 :探讨针刺镇痛与中枢 c AMP和 c GMP含量变化之间的关系。方法 :运用放射免疫分析法 ( RIA)测定大鼠电针前后不同脑区 c AMP和 c GMP含量的变化。结果 :电针 30 min提高大鼠痛阈的同时 ,使间脑 c AMP、端脑 c GMP含量显著降低 ( P&...目的 :探讨针刺镇痛与中枢 c AMP和 c GMP含量变化之间的关系。方法 :运用放射免疫分析法 ( RIA)测定大鼠电针前后不同脑区 c AMP和 c GMP含量的变化。结果 :电针 30 min提高大鼠痛阈的同时 ,使间脑 c AMP、端脑 c GMP含量显著降低 ( P<0 .0 5 ) ,脑干 c GMP含量显著升高 ( P<0 .0 5 )。结论展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 30671248)"Blue Project" of Jiangsu Province and the Student Research Train-ing (SRT) Project of Nanjing Agricultural University (Grant No. 0506A11)
文摘Carbon monoxide (CO) has recently proven to be an important bioactive or signaling molecule in mammalian cells. Its effects are mainly mediated by nitric oxide (NO) and cyclic GMP (cGMP). In Vicia faba leaves, CO production and heme oxygenase (HO) activity, an important CO synthetic enzyme, are first reported to increase in response to ABA treatment, which could result in stomatal closure. Inter- estingly, ABA-induced stomatal closure in V. faba guard cells is partially blocked when the synthetic CO inhibitor ZnPP, or the CO/NO scavenger Hb is added. Furthermore, we show that, exogenously applied CO donor, hematin, and CO aqueous solution not only result in the enhancement of CO release, but also time-dependently induce stomatal closure, and the latter is mimicked by the application of an NO donor SNP. The above-mentioned stomatal closure effects are differentially reversed by the addition of tungstate, a potent inhibitor of NO synthetic enzyme nitrate reductase (NR), the specific NO scavenger cPTIO, ZnPP, or Hb. During treatment for 4 h, SNP, 0.01% CO aqueous solution or hematin significantly triggers NO synthesis, whereas cPTIO, or tungstate approximately fully inhibits NO fluorescence. Ad- ditionally, application of the GC inhibitor ODQ blocks CO-induced stomatal closure. This inhibition could be reversed when 8-Br-cGMP is added. Thus, the above results suggest that CO produced by HO is involved in ABA-induced stomatal closure, and NO and cGMP may function as downstream interme- diates in the CO signaling responsible for stomatal closure.
基金This work was supported by a grant from the National Nature Science Foundation of China(No.C30572005)
文摘Background The form deprivation （FD） reduces spatial contrasts and induces myopia. Nitric oxide and cyclic guanosine monophosphate （cGMP） are involved in visual signal transmission. This study investigated changes in nitric oxide synthase （NOS） activity and cGMP concentration in ocular tissues in acute and chronic form deprivation myopia. Methods Guinea pigs had one eye covered by translucent glass for 7, 14 or 21 days. Untreated litter mates were used as controls. NOS activity and cGMP concentrations in the retinal, choroidal and scleral tissues of FD eyes and control eyes were analyzed by radioimmunoassay after various durations of FD. The expression of NOS subtypes was identified by immunohistochemistry. Results Myopia was successfully induced in FD eyes after 14 days. Compared with control groups, the retinal NOS activity and cGMP concentrations in the FD eyes significantly increased after 14 and 21 days while the retinal NOS activity in the FD eyes was transiently suppressed by 7 days of FD. The NOS activity and cGMP concentrations of choroid and sclera in the FD eyes were higher than in the control groups at 21 days. The three isoenzymes of nitric oxide synthase were detected in the ocular tissues of guinea pigs. Conclusions The NOS activity and cGMP concentrations were upregulated after chronic FD and the retinal NOS activity was transiently suppressed at acute FD. The function of elevated NOS activity may be mediated by cGMP.
文摘目的 :探讨针刺镇痛与中枢 c AMP和 c GMP含量变化之间的关系。方法 :运用放射免疫分析法 ( RIA)测定大鼠电针前后不同脑区 c AMP和 c GMP含量的变化。结果 :电针 30 min提高大鼠痛阈的同时 ,使间脑 c AMP、端脑 c GMP含量显著降低 ( P<0 .0 5 ) ,脑干 c GMP含量显著升高 ( P<0 .0 5 )。结论
