Sensing light signals not only provide the image vision for us,but also regulates many important physiological functions such as circadian-rhythm photoentrainment,emotion,sleep,pupillary light reflex,etc.–functions r...
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Sensing light signals not only provide the image vision for us,but also regulates many important physiological functions such as circadian-rhythm photoentrainment,emotion,sleep,pupillary light reflex,etc.–functions referred to collectively as"non-image vision".A small subset of retinal ganglion cells(ip RGCs),which directly project to the brain regions for non-image vision,can sense light by themselves,i.e.,intrinsically photosensitive,by virtue of their expression of melanopsin,a recently discovered visual *** found that ip RGCs employ phosphatidylinositol signal pathway for translating light signal into photocurrents,which closely resembles the phototransduction of invertebrates,such as *** molecular identities of the phototransduction were characterized,which include 4 and TRPC6,7 ***,ip RGCs are very efficient in drivingβPLC-non-image vision *** only needs few hundred ip RGCs each absorbing a single photon to induce non-image vision physiological functions(e.g.,pupillary light reflex).
目的研究蛋白激酶Mζ(PKMζ)对慢性内脏痛大鼠痛觉敏感性的影响并探讨其脊髓作用机制。方法采用将出生后第2～21天的SD大鼠每天固定母婴分离3小时的方法建立慢性内脏痛模型,通过测量成年大鼠(8周后)腹外斜肌对结直肠扩张(CRD)引起的放电反应来选择建模成功的大鼠进行研究。采用western blot方法观察PKMζ及磷酸化PKMζ在模型大鼠脊髓胸腰段和腰骶段的表达情况。在椎管插管术7天后选择活动自如并经过利多卡因筛选的模型大鼠和正常大鼠;观察单次鞘内注射不同剂量PKMζ抑制剂ZIP前后,腹外斜肌在不同压力CRD下放电幅值的差异。另外,采用旷场试验检测PKMζ抑制剂ZIP对模型和正常大鼠运动功能的影响。结果 1.与正常大鼠比较,慢性内脏痛模型大鼠腹外斜肌放电幅值显著增加(P<0.01)即模型大鼠内脏痛敏反应显著高于对照大鼠;同时模型大鼠远端降结肠及直肠局部组织未见明显病理改变。2.通过western blot的方法观察结果显示,与正常大鼠相比,PKMζ在慢性内脏痛大鼠脊髓胸腰段和腰骶段的表达无明显变化;而磷酸化PKMζ在慢性内脏痛大鼠脊髓胸腰段和腰骶段的表达显著高于正常大鼠。3.鞘内注射ZIP,可剂量依赖性显著降低慢性内脏痛大鼠内脏痛敏反应,且最佳作用时间约为给药后0.5 h。1正常大鼠鞘内注射不同剂量PKMζ抑制剂ZIP前后,在20-80 mm Hg CRD压力下腹外斜肌放电幅值差异均无统计学意义;2慢性内脏痛模型大鼠鞘内注射1μg ZIP前后,在20-80 mm Hg CRD压力下腹外斜肌放电幅值差异无统计学意义;鞘内注射5μg和10μg ZIP前后,在20 mm Hg CRD压力下腹外斜肌放电幅值差异无统计学意义,而在40-80 mm Hg CRD压力下腹外斜肌放电幅值差异有统计学意义(P<0.05)。3采用旷场试验检测发现,鞘内注射10μg PKMζ抑制剂ZIP对模型和正常大鼠的运动功能影响无显著差异。结论:磷酸化PKMζ可能参与了大鼠慢性内脏痛脊髓中枢敏化的形成。
Hematopoietic stem cells(HSCs)are a population of multipotent cells that can self-renew and differentiate into all blood *** development must be tightly controlled from cell fate determination to self-maintenance duri...
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Hematopoietic stem cells(HSCs)are a population of multipotent cells that can self-renew and differentiate into all blood *** development must be tightly controlled from cell fate determination to self-maintenance during *** involves a panel of important developmental signaling pathways and other factors which act synergistically within the HSC population and/or in the HSC *** conserved processes of HSC development plus many other developmental advantages make the zebrafish an ideal model organism to elucidate the regulatory mechanisms underlying HSC programming in vertebrates.I will talk about our recent progress on zebrafish HSCs using functional genomics approaches,with particular focus on how developmental signaling controls hemogenic endothelium-derived HSC *** hematopoietic stem cell system is a paradigm for stem cell *** of the zebrafish model to study signaling regulation of HSCs in vivo has resulted in a great deal of information concerning HSC biology in *** new findings facilitate a better understanding of molecular mechanisms of HSC programming,and will provide possible new strategies for generation and/or expansion of transplantable and functional HSCs in vitro.
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