Obestatin对血浆ghrelin和nesfatin-1水平及胃排空的影响

目的:探讨侧脑室注射obestatin对大鼠血浆酰基化ghrelin、去酰基化ghrelin、nesfatin-1水平的影响以及对胃排空的调控。方法:侧脑室注射obestatin,采用酶免疫测定(EIA)法检测血浆酰基化ghrelin、去酰基化ghrelin、nesfatin-1水平以及胃排空率的变化。结果:侧脑室分别注射0.1、0.3或1.0 nmol obestatin,大鼠血浆酰基化ghrelin、去酰基化ghrelin以及nesfatin-1水平无显著改变(P0.05),且酰基化ghrelin与去酰基化ghrelin比率无显著改变(P0.05);侧脑室注射obestatin,大鼠摄食量无显著改变,但胃排空率明显增加(P0.05);胃排空率明显延迟(P0.05)。与侧脑室注射1.0 nmol Obestatin组相比,注射1.0 nmol Obestatin+CRF,大鼠摄食量无显著改变,胃排空率明显延迟(P0.05)。各组摄食量及进入十二指肠内食物量无明显差异(P0.05)。结论:中枢obestatin促进大鼠的胃排空,可能与h/r CRF通路有关。     

侧脑室注射orexin-A对大鼠昼夜摄食的影响

目的:探讨侧脑室注射orexin-A对大鼠昼夜摄食的影响。方法:将Wistar大鼠随机分组,采用单剂量侧脑室注射和连续侧脑室注射以及外周注射法,分别于日间和夜间给药,测量大鼠24小时内各阶段的摄食量以及相应生化指标。结果:在光照期间,侧脑室微量注射orexin-A,大鼠4小时内摄食量显著增加(P0.05),且呈剂量依赖关系(P0.05)。在夜间初期(18:00)侧脑室注射orexin-A,大鼠食物摄入量无显著差异(P0.05)。但在中午12:00给予侧脑室注射orexin-A,注射后4小时内大鼠摄食量显著高于NS对照组(P0.05)。连续8日给予orexin-A侧脑室注射,可使注射后日间摄食量显著增加(P0.05),而夜间摄食量显著减少(P0.05),但24小时内总的摄食量不变(P0.05)。orexin-A并未改变棕色脂肪组织温度、末梢血糖、血浆瘦素等指标的水平。结论:orexin-A对大鼠摄食的调节具有昼夜节律性。     

NUCB2/nesfatin-1对小鼠摄食行为的调控及机制

目的:探讨NUCB2/nesfatin-1对小鼠摄食行为的调控及机制。方法:利用侧脑室埋管,免疫组化染色等方法,探讨侧脑室和外周注射nesfatin-1对小鼠摄食行为的影响。结果:侧脑室注射不同剂量nesfatin-1(0.3μg,1μg,3μg),注药后4 h夜间进食量明显减少,且呈显著剂量依赖关系(t=2.61~4.78,P0.05~0.01),侧脑室注射3μg nesfatin-1,小鼠前3小时累积摄食量明显降低(t=8.69~10.73,P0.01),且持续降低12小时(t=2.64,P0.05),同时餐间间隔时间明显延长(t=2.66,P0.05),每分钟/1-4 h进食量明显降低(t=2.63,P0.05),且进食每克食物所用时间明显增加(t=3.02,P0.05)。在下丘脑弓状核,外侧区和背内侧核均有NUCB2/nesfatin-1免疫阳性神经元表达。皮下或腹腔注射nesfatin-1,小鼠进食量和进食行为均无显著改变(P0.05)。结论:中枢nesfatin-1可抑制小鼠摄食行为。     

侧脑室注射Orexins对大鼠摄食的影响及机制

目的:探讨侧脑室注射orexins(食欲素)、NPY(神经肽Y)、MCH(黑色素聚集激素)和甘丙肽对大鼠摄食的影响及其机制。方法:将成年雄性Wistar大鼠随机分为对照组、侧脑室注射组和室旁核(PVN)注射组。通过套管将orexin-A、orexin-B、NPY、MCH和甘丙肽分别注射至侧脑室和PVN内,随后测量大鼠食物摄入量,并检测PVN、弓状核(ARC)和VMH内c-fos的表达。结果:与对照组比较,侧脑室注射NPY、MCH和orexin-B 2 h后,大鼠摄食量显著增多(P0.05)。相较于orexin-B和MCH,NPY对摄食的影响更显著(P0.05)。与NS对照组比较,侧脑室注射甘丙肽和orexin-A 1 h后,大鼠摄食量显著增多(P0.05)。与NS对照组比较,侧脑室注射orexin-A可显著增加c-fos在PVN和ARC中的表达,在VMH中效应较弱(P0.05)。与NS对照组比较,PVN注射NPY能显著增加大鼠2 h摄食量(P0.05),PVN注射orexin-A能显著增加大鼠2 h和4 h摄食量(P0.05)。结论:orexins与可促进大鼠摄食,此效应可能通过下丘脑参与摄食调控中枢PVN和ARC而实现的。     

中枢nesfatin-1对大鼠夜间摄食和胃排空的影响

目的:观察中枢nesfatin-1对大鼠夜间摄食和胃排空的影响。方法:大鼠经腹腔注射硫酸仲丁巴比妥(100~150 mg/kg)麻醉,侧脑室、第四脑室或小脑延髓池注射nesfatin-1或CRF受体拮抗剂astressin-B或astressin2-B,观察对摄食、胃排空的影响。结果:侧脑室注射nesfatin-1后大鼠第3-6 h夜间进食量(t=3.05~3.58,P0.01)和3 h和6 h的累积进食量(t=5.90~12.1,P0.01)明显减少,nesfatin-1的该抑制效应可被预先侧脑室注射astressin-B或astressin2-B阻断(t=1.06~2.22,P0.05)。第四脑室或小脑延髓池注射nesfatin-1后大鼠夜间摄食量在第1h就明显减少(t=2.59~6.26,P0.05~0.01),持续减少至5-6h(t=1.69~7.42,P0.05~0.01)。侧脑室注射不同剂量nesfatin-1(0.05或0.5μg)20 min后GE率明显降低,且随注射剂量增大,GE率越低(t=3.25~4.67,P0.01)。若预先给予大鼠CRF受体拮抗剂astressin2-B(30μg)再注射nesfatin-1(0.5μg),nesfatin-1抑制大鼠胃排空效应明显减弱(t=2.45~2.85,P0.05)。禁食24 h后再喂食2 h,大鼠下丘脑中nesfatin-1表达明显增加(t=2.87,P0.05),禁食24 h后血浆nesfatin-1水平明显降低(t=1.51,P0.05)。结论:Nesfatin-1抑制摄食作用可能由nesfatin-1和CRF2信号系统共同调节。     

顺铂化疗对下丘脑、血浆ghrelin和orexin 表达的影响

目的:观察顺铂化疗对下丘脑、血浆ghrelin、orexin表达和摄食量的影响。方法:Real-time PCR、ELISA法观察顺铂对大鼠下丘脑、血浆ghrelin、orexin表达及摄食量的影响;19名接受顺铂经导管动脉灌注化疗(TAI)的肝细胞患者(HCC),ELISA法检测化疗前和化疗后血浆ghrelin、orexin的变化,用直观类比标度(VAS)(0-10)评估食欲和摄食量。结果:每日腹腔注射顺铂6 mg/kg,1-5 d大鼠摄食量均显著减少(P0.05),且1-4 d血浆酰化ghrelin显著降低(P0.05),5d时浓度仍低于对照组,但无统计学意义。血浆非酰化ghrelin和总的血浆ghrelin没有明显变化(P0.05),而1-5天血浆orexin水平均明显降低(P0.05);顺铂注射1 d后,大鼠下丘脑ghreilin和orexin的mRNA表达量均显著减少(P0.05),ghrelin mRNA变化持续3 d,orexin mRNA在化疗后5 d仍低于对照组(P0.05);肝细胞癌患者化疗后1至8 d的摄食量明显降低,1 d和2 d时的血浆酰化ghrelin显著低于化疗前水平(P0.05)。3 d时逐渐恢复,化疗后3 d、4 d和7 d时血浆酰化ghrelin浓度与化疗前无统计学差异(P0.05)。血浆非酰化ghrelin和总的血浆ghrelin没有明显变化(P0.05);化疗后1~4 d时血浆orexin浓度均显著降低(P0.05),化疗后7 d时orexin基本恢复到化疗前水平(P0.05)。结论:顺铂可降低大鼠下丘脑和血浆ghrelin、orexin的mRNA表达,HCC的TAI会降低血浆酰化ghrelin、orexin、和摄食量。     

Ghrelin对大鼠摄食的影响及orexins信号通路的调控

目的:探究Ghrelin对大鼠摄食的影响及orexins信号通路的调控作用。方法:采用免疫组织化学染色的方法观察Ghrelin免疫阳性神经元轴突末梢与orexin神经元的突触联系以及下丘脑外侧区(LHA)内c-fos的表达。侧脑室注射抗-orexin-A IgG和抗-orexin-B IgG混合液、抗-黑色素浓集激素(MCH)IgG、NPY-1受体拮抗剂后测量大鼠摄食量,观察其对ghrelin诱导摄食的影响。结果:Ghrelin免疫阳性神经元轴突末梢与orexin神经元的突触相接触。侧脑室注射ghrelin可诱导orexin神经元内c-fos表达,但是没有引起MCH神经元内c-fos的表达。预先注射抗-NPY IgG抗体,ghrelin仍然可诱导orexin神经元内c-fos表达。侧脑室预先注射抗-orexin-A IgG和抗-orexin-B IgG抗体可减弱ghrelin促摄食作用,但是预先注射抗-MCH IgG抗体对ghrelin诱导的摄食作用没有明显影响。注射NPY受体拮抗剂可进一步加强抗-orexin-A IgG抗体和抗-orexin-B IgG抗体对ghrelin诱导摄食的抑制效应。结论:ghrelin可能与orexin系统相互作用共同参与摄食和能量平衡的调控。     

糖尿病大鼠ghrelin和nesfatin-1表达动力学及其调控

目的:探讨STZ诱导糖尿病大鼠ghrelin和nesfatin-1动力学及分泌调节变化。方法:STZ诱导糖尿病大鼠模型;采用葡糖糖脱氢酶分析法测量血浆葡萄糖水平;免疫放射分析检测血浆ghrelin、nesfatin-1、胰岛素、胰岛素样生长因子1(IGF-1)、生长激素(GH)含量;采用real-time PCR检测ghrelin m RNA水平变化;免疫组化观察ghrelin和nesfatin-1免疫活性细胞数量。结果:糖尿病大鼠体重显著降低(t=23.16,P<0.01),血糖水平显著升高(t=22.55,P<0.01),血浆胰岛素和IGF-1水平显著降低(t=6.50,t=24.13,P<0.01),但GH水平显著升高(t=3.30,P<0.05)。糖尿病大鼠血浆总ghrelin(t=7.03,P<0.01)和活性ghrelin(t=3.33,P<0.05)水平均显著升高,血浆nesfatin-1水平则显著降低(t=6.24,P<0.01);糖尿病大鼠血浆总ghrelin与GH(r=0.81,P<0.01)和IGF-1水平(r=-0.58,P<0.01)呈显著相关性;与对照组大鼠相比,糖尿病大鼠胃总ghrelin(t=16.86,P<0.01)和活性ghrelin(t=3.30,P<0.05)水平均显著降低;而胃nesfatin-1(t=7.93,P<0.01)水平则显著升高。胃总ghrelin水平与血浆IGF-1水平呈明显相关性(r=0.65,P<0.01);与对照组大鼠相比,糖尿病大鼠胃ghrelin m RNA表达水平显著升高(t=16.8,P<0.01),胃底ghrelin免疫活性细胞数量显著减少(t=3.98,P<0.01);实验中给予大鼠自由饮食,糖尿病大鼠血浆总ghrelin水平显著增加(t=7.53,P<0.01),nesfatin-1水平显著降低(t=5.46,P<0.01)。糖尿病大鼠注射胰岛素后,可使增加的ghrelin水平(t=1.76,P=0.11)和降低的nesfatin-1水平接近正常(t=1.96,P=0.06);且胰岛素可显著反转糖尿病大鼠胃总ghrelin(t=8.54,P<0.01)和nesfatin-1水平(t=2.42,P<0.05);以及注射胰岛素后,糖尿病大鼠胃底ghrelin细胞显著增加,nesfatin-1细胞明显减少(t=3.21,t=2.59,P<0.05)。结论:Ghrelin或nesfatin-1参与糖尿病大鼠能量平衡调控。     

中枢注射抗Orexin抗体对禁食大鼠摄食的抑制作用

目的:探讨中枢注射抗Orexin抗体对禁食大鼠摄食的抑制作用。方法:采用免疫组织化学法和蛋白质免疫印迹分析法,对Orexin抗体的特异性进行了检测,分析Orexin阳性神经元和阳性神经纤维在大脑中的分布。给予24 h禁食大鼠中枢注射抗Orexin抗体,计算其对大鼠食物摄入量的影响。结果:蛋白质免疫印迹分析显示,Orexin抗体能够检测到合成的Orexin-A。免疫组织化学分析显示,Orexin阳性神经元存在于外侧下丘脑区域和穹窿周核,Orexin阳性神经纤维大量投射至弓状核、下丘脑室周核和下丘脑室旁核、菱形丘脑核、丘脑室旁核、缰内侧核和纹质丘脑、中脑的中央灰质区、蓝斑核和中缝核、脑桥和髓质的网状结构、对疑核和迷走神经复合体。与注射羊血清相比,给予45μg/10μL抗Orexin抗体侧脑室注射则抑制了大鼠的食物摄入量(P0.05)。高剂量抗Orexin抗体能显著地抑制大鼠摄食,并且呈剂量依赖关系(P0.05)。结论:中枢注射抗Orexin抗体对禁食大鼠摄食具有抑制作用,并呈剂量依赖关系。     

下丘脑LHA-VMH Ghrelin信号通路对肥胖大鼠摄食选择、胃肠道运动及自发活动的影响及机制研究

目的:探究下丘脑外侧区(LHA)-腹内侧核(VMH)ghrelin信号通路对肥胖大鼠的摄食选择、胃肠道运动及自发活动的影响。方法:采用免疫组织化学方法检测大鼠LHA中ghrelin受体的表达;观察LHA注射ghrelin对大鼠摄食选择胃肠道运动及自发活动的影响;电损毁VMH,观察LHA注射ghrelin对大鼠摄食的影响。结果:免疫组化结果显示,大鼠下丘脑LHA中存在ghrelin受体,且LHA-VMH之间存在纤维投射;大鼠LHA微量注射ghrelin后,肥胖(DIO)大鼠及肥胖抵抗(DR)大鼠的正常饮食、高脂饮食及高糖饮食均高于正常大鼠,但预注射ghrelin受体拮抗剂[D-Lys3]-GHRP-6 (DLS)能够阻断这种作用;而电损毁大鼠VMH,显著减弱了ghrelin对正常大鼠、DIO大鼠及DR大鼠的促摄食作用。大鼠LHA微量注射ghrelin后,正常大鼠、DIO大鼠及DR大鼠的自发活动中,X轴、Y轴方向上的活动增加,且总活动增加,但Z轴方向上活动无明显改变;此外,LHA注射ghrelin,DIO大鼠及DR大鼠的胃肠道转运速率明显加快,且DR大鼠胃肠道转运速率增加更为明显,而预注射ghrelin受体拮抗剂[D-Lys3]-GHRP-6(DLS)显著阻断ghrelin的促胃肠道转运作用。结论:下丘脑LHA-VMH ghrelin信号通路参与调节正常大鼠、DIO及DR大鼠的摄食选择、胃肠道运动及自发活动。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism