电刺激POAH对IL-1β作用下兔VSA温敏神经元放电的影响

目的和方法:为了从细胞水平进一步探讨发热时体温正、负调节中枢的调节机制,本实验采用微电极细胞外记录技术,在26只新西兰兔脑腹中隔区(ventralseptalarea,VSA)记录了温敏神经元单位放电,观察电刺激下丘脑视前区(preopticanteriorhypothalamus,POAH)对致热原IL-1_β作用下兔VSA温敏神经元放电的影响。结果:(1)侧脑室注射的白介素-1_β(IL-1_β)能使VSA热敏神经元放电频率增加,冷敏神经元放电减少,而侧脑室注射等量人工脑脊液(ACSF)对热敏神经元和冷敏神经元的放电均无明显影响。(2)电刺激POAH可反转致热原IL-1_β对VSA热敏神经元和冷敏神经元的上述作用。结论:在致热原作用下的体温调节中,正调节中枢POAH和负调节中枢VSA具有密切的相互作用。     

电刺激POAH对IL - 1_β 作用下兔VSA温敏神经元放电的影响(英文)

目的和方法 :为了从细胞水平进一步探讨发热时体温正、负调节中枢的调节机制 ,本实验采用微电极细胞外记录技术 ,在 2 6只新西兰兔脑腹中隔区 (ventralseptalarea ,VSA)记录了温敏神经元单位放电 ,观察电刺激下丘脑视前区 (preopticanteriorhypothalamus,POAH)对致热原IL - 1β 作用下兔VSA温敏神经元放电的影响。结果 :(1)侧脑室注射的白介素 - 1β(IL - 1β)能使VSA热敏神经元放电频率增加 ,冷敏神经元放电减少 ,而侧脑室注射等量人工脑脊液 (ACSF)对热敏神经元和冷敏神经元的放电均无明显影响。 (2 )电刺激POAH可反转致热原IL- 1β 对VSA热敏神经元和冷敏神经元的上述作用。结论 :在致热原作用下的体温调节中 ,正调节中枢POAH和负调节中枢VSA具有密切的相互作用     

电刺激VSA对IL-1_β作用下兔POAH温敏神经元放电的影响

目的和方法：本实验采用微电极细胞外记录,在３２只新西兰兔下丘脑视前区（ＰＯＡＨ）记录温敏神经元单位放电,观察电刺激腹中膈区（ＶＳＡ）对致热原ＩＬ－１β作用下兔ＰＯＡＨ温敏神经元放电的影响。结果：（ｌ）侧脑室注射白介素－１β（ＩＬ－１β）能使ＰＯＡＨ热敏神经元放电减少,冷敏神经元放电增加;而侧脑室注射人工脑脊液（ＡＣＳＦ）对热敏神经元和冷敏神经元的放电均无明显影响。（２）电刺激ＶＳＡ可反转ＩＬ－１β对ＰＯＡＨ热敏神经元和冷敏神经元的上述作用。结论：ＶＳＡ可能作为负调节中枢参与致热原作用下的体温调节。     

电刺激腹中隔区对兔视前区前下丘脑温敏神经元放电的影响

目的和方法:采用玻璃微电极细胞外引导单位神经元放电的方法,观察电刺激兔腹中隔区(VSA)时,视前区-下丘脑前部(POAH)温度敏感神经元放电频率的变化。结果:电刺激腹中隔区可使视前区-下丘脑前部热敏神经元放电频率增加,冷敏神经元放电频率减少。结论:腹中隔区可能通过影响视前区-下丘脑前部温敏神经元放电频率而参与体温调节。     

电刺激POAH对致热原作用下兔VSA温敏神经元放电的影响

本室前一阶段的工作表明 :ＶＳＡ可能作为负调节中枢参与致热原作用下的体温调节 ,为了从细胞水平进一步探讨发热时体温正、负调节中枢的调节机制 ,本实验采用微电极细胞外记录技术 ,在 2 6只新西兰兔腹中膈区 (ｖｅｎｔｒａｌｓｅｐｔａｌａｒｅａ ,ＶＳＡ)记录了温敏神经元单位放电 ,观察电刺激下丘脑视前区 (ｐｒｅｏｐｔｉｃａｎｔｅｒｉｏｒｈｙｐｏｔｈａｌａｍｕｓ,ＰＯＡＨ)对致热原ＩＬ - 1 β 作用下 ,兔ＶＳＡ温敏神经元放电的影响。结果如下 :( 1 )侧脑室注射白介素 - 1 β(ＩＬ - 1 β)能使ＶＳＡ热敏神经元放电频率增加 (Ｐ <…     

电刺激VSA对致热原作用下兔POAH温敏神经元放电的影响

本实验采用微电极细胞外记录及脑内电刺激技术,在３２只新西兰兔下丘脑视前区（ｐｒｅｏｐｏｔｉｃａｎｔｅｒｉｏｒｈｙｐｏｔｈａｌａｍｕｓ,ＰＯＡＨ）记录了温敏神经元单位放电,观察电刺激腹中膈区（ｖｅｎｔｒａｌｓｅｐｔａｌａｒｅａ,ＶＳＡ）对致热原作用下兔ＰＯＡＨ温敏神经元放电的影响。（一）　致热原对ＰＯＡＨ热敏神经元放电的影响：在９例热敏神经元中,观察到侧脑室注射ＩＬ－１β后１、３和５ｍｉｎ,热敏神经元放电频率由６－３２±４－７９分别减少到３－７５±３－４６（Ｐ＜０－０５）、１－６８±１－９８（Ｐ＜…     

中枢白细胞介素-1β介导束缚应激性升压反应的中枢机制

目的:研究中枢白细胞介素-1β(IL-1β)在束缚应激诱发的升压反应的中枢机制。方法:利用清醒大鼠心血管遥感监测系统、脑立体定位微量注射系统、神经电生理记录系统来观察中枢IL-1β在束缚应激诱发的升压反应机制中的作用;以及与延髓头端腹外侧区神经元放电变化之间的关系。结果:束缚应激可诱导升压反应,侧脑室注射IL-1ra可衰减束缚应激诱导的升压反应;直接将IL-1β注入侧脑室亦可诱导大鼠血压升高,同时伴有延髓头端腹外侧区神经元细胞外放电频率增加,二者呈明显的相关关系(r=0.98,P<0.05)。结论:中枢IL-1β介导束缚应激诱发的升压反应,其作用机制与延髓头端腹外侧区密切相关。     

侧脑室注射肾上腺髓质素激活去缓冲神经大鼠最后区神经元

目的观察侧脑室注射肾上腺髓质素(AM)对去缓冲神经大鼠最后区神经元自发放电和Fos蛋白表达的影响。方法应用细胞外记录的电生理学方法,观察雄性SD大鼠神经元自发放电活动;用免疫组化方法检测Fos蛋白的表达。结果侧脑室注射AM(1,3nmol/kg)诱发最后区出现大量Fos样免疫阳性神经元(Fos-LI),最后区神经元自发放电频率明显增加;降钙素基因相关肽受体拮抗剂CGRP8-37(30nmol/kg)可明显减弱AM的效应。结论AM对最后区神经元有直接兴奋作用,降钙素基因相关肽受体介导这一效应。     

催产素抑制大鼠海马CA1神经元电活动

应用细胞外记录单位放电技术,观察催产素(oxytocin,OT)对大鼠左背侧海马CA1神经元自发和诱发电活动的作用以及酚妥拉明对OT作用的影响。侧脑室注射1,10和100ng／5μLOT分别使海马CA1内60％(9／15)、73．3％(11／15)和75％(9／12)的神经元自发放电频率降低;不同剂量OT也可抑制神经元对电刺激坐骨神经产生的诱发放电且剂量依赖关系明显。侧脑室预先注射催产素受体拮抗剂[d(CH2)5-OVT](200ng／2．5μL)能阻断OT(10ng,5μL)对CA1神经元自发和诱发放电的抑制作用。酚妥拉明(10ng／2．5μL)可明显减弱OT(10ng,5μL)的作用。结果表明OT对海马CA1神经元自发和诱发电活动的抑制作用是通过OT受体介导的,也与α-肾上腺素能受体有关。     

白细胞介素-10抑制人肾系膜细胞环氧化酶-2表达及其催化的前列腺素E2释放的实验研究

目的:观察IL-10对IL-1β诱导的人系膜细胞(HMC)前列腺素E₂(PGE₂)释放及环氧化酶-2(cyclooxygenase-2,COX-2)基因和蛋白表达的影响。方法:应用放射免疫测定法检测HMC培养上清中PGE₂,应用RT-PCR和Westernblot分别检测COX-2mRNA和蛋白水平。结果:①IL-1β显著上调PGE₂释放及COX-2基因和蛋白的表达(P均＜0.01);②IL-10对基础状态下PGE₂释放及COX-2基因和蛋白表达无明显影响(P＞0.05);③IL-10可呈剂量依赖性地下调IL-1β诱导的PGE₂释放及COX-2mRNA和蛋白表达(P＜001)。结论:IL-10抑制IL-1β诱导的HMCPGE₂释放及COX-2表达,提示IL-10对HMC具有多方面抗炎作用。     

Effects of electrical stimulation of VSA on firing characteristics of thermosensitiveneurons in POAH of rabbits treated with pyrogen

Effects of electrical stimulation of VSA on firing characteristics of thermosensitive neurons in POAH of rabbits treated with pyrogen     

Thermosensitive neurons in the brain

Since the discovery of thermosensitive neurons in the POAH, numerous papers have been published suggesting the primary importance of these neurons in thermoregulation. The basic properties of the neurons per se were well studied in cultured explants and slice preparations, outside of the influences of anesthesia and extrahypothalamic inputs. Attempts have been made to classify thermosensitive neurons according to firing rate and response pattern and to correlate each neuron group with thermoregulatory responses. In complex thermoregulatory networks, thermosensitive neurons are always under the influences of extrahypothalamic and non-thermal inputs. Most studies on POAH neurons have shown a variety of responses, some contrary to others; for instance, three-fourths of POAH warm-sensitive neurons may be facilitated by scrotal warming whereas the rest are inhibited or uninfluenced. These inconsistencies in responses among thermosensitive neurons, observed also in the effects of chemicals, may reflect different roles of POAH thermosensitive neurons in a variety of thermoregulatory responses. Unit recordings from conscious animals over long periods, together with observation on whole body responses, are expected to throw more light on the physiological significance of POAH thermosensitive neurons.     

Effects of carbon dioxide inhalation on preoptic thermosensitive neurons

The effects of inspired CO₂ on preoptic thermosensitive neurons were studied in urethanized rats. Most of the neurons changed their activities diversely while the rat breathed 4%, 7%, and 10% CO₂ gas mixtures. Half of the neurons increased activity during CO₂ inhalation, but activity was not necessarily intensified by elevating CO₂ concentration. Thermosensitive neurons tended to increase activity more than thermally insensitive neurons. The effect of CO₂ on sensitivity of thermosensitive neurons was also examined by regression of neuronal activity on preoptic temperature. The slopes of the regression lines during CO₂ inhalation did not differ significantly from those during air inhalation in either warm-sensitive or cold-sensitive neurons, but CO₂ did elevate the intercepts in most instances (P<0.01). However, ifP<0.05 is accepted as a significance level, the slopes of the regression lines for warmsensitive neurons tended to decrease during CO₂ inhalation (9/39 pairs). The present results indicate that preoptic thermosensitive neurons generally increase their activities and modify their thermosensitivities during CO₂ inhalation.     

Effects of electrical stimulation of the tooth pulp and phrenic nerve fibers on C1 spinal neurons in the rat

 Effects of electrical stimulation of the ipsilateral tooth pulp (TP) on C₁ spinal neurons were determined in 33 anesthetized rats. One hundred and seven neurons responded to TP stimulation. In 10 rats, the activity of 18 C₁ spinal neurons and the amplitude of a digastric electromyogram (dEMG, n=10) increased proportionally during the TP stimulation at an intensity of 1–3 times the threshold for jaw-opening reflex (JOR). Excitatory receptive somatic fields were examined in 61 neurons. Somatic field locations of many neurons (67.2%) involved the ipsilateral face, neck, and jaw. The activity of 45 neurons was increased by both noxious pinch and brushing hair. Of the 107 C₁ spinal neurons responding to TP stimulation, 55 were tested to determine the effects of electrical stimulation of the ipsilateral phrenic nerve (PN) above the heart. Twenty-eight of 55 neurons tested were excited; no change in activity was seen for the remaining 27 neurons. The activity of six neurons increased as the intensity of PN stimulation was increased. Excitatory receptive somatic fields were determined in 28 neurons, and somatic field locations of 17 neurons (60.7%) included the ipsilateral face, neck, and jaw. Both noxious pinch and brushing hair excited all 28 neurons. These results suggest that there may be the convergence of face, neck, jaw, TP, and PN afferents on the same C₁ spinal neurons in the rat. Received: 23 June 1998 / Accepted: 11 December 1998     

Comparison of influences of stimulation of the Ammon's horn and subiculum to thermosensitive preoptic and septal neurons

Thermosensitive preoptic and septal (PO/SP) neurons were studied for their responsiveness to electrical stimulation of the dorsal Ammon's horn (DAH) and the ventral subiculum (VSB) of the hippocampal formation in the rat. DAH stimulation affected only 14 (16%) of 90 PO/SP thermosensitive neurons whereas VSB stimulation affected 77 (86%) units. The results suggests that the DAH has no major role in thermoregulation in the rat.Department of Physiology, University of Occupational and Environmental Health, School of Medicine, Kitakyushu 807, Japan     

Effects of peripheral chemo- and baro-receptor denervation on responses of preoptic thermosensitive neurons to inspired CO2

The purpose of this study was to see if the responses of thermosensitive neurons in the preoptic (PO) area to inspired CO₂ seen in spontaneously ventilated rats were indirectly driven by reflexive changes in respiration and circulation. In urethanized, paralyzed, and artificially ventilated (AV) rats, the effects of 10% CO₂ inhalation on PO thermosensitive neurons were examined by regression of neuronal activity on PO temperature. The experiments were made in intact rats and in rats whose peripheral chemo- and baro-receptors were denervated (AVD). In both AV and AVD rats, the slope of the regression line decreased significantly (P<0.05) during CO₂ inhalation in half of the warmsensitive neurons studied (64.3% in AV rats, 41.7% in AVD rats). Peripheral chemo- and baro-receptors thus do not appear to be responsible for decreased thermosensitivities of warm-sensitive neurons during CO₂ inhalation. The tendency for activities of warm-sensitive neurons to increase progressively at lowerT _po was seen during CO₂ inhalation in both AV and AVD rat. However, the average differences in mean firing rate between 10% CO₂ and air inhalations were 2–3 imp/s greater at anyT _po in AV rats than in AVD rats. In AVD rats, warm-sensitive neurons were rather inhibited by CO₂ at higherT _po. Excitation of warm-sensitive neurons during CO₂ inhalation in AV rats, which was independent ofT _po, was considered to be caused by the signals from peripheral receptors.     

异丙肾上腺素舒血管作用机制的在体实验研究

目的:研究NOS(一氧化氮合酶)抑制剂对异丙肾上腺素(isoprenaline)产生的血管舒张作用的影响及涉及的β-肾上腺素能受体(β-AR)亚型,探讨NO是否作为β-AR激动后信号转导过程中的信使物质参与β-AR激动产生的血管舒张。方法:利用家兔股动脉恒流灌注模型。结果:(1)Isoprenaline产生浓度依赖的血管舒张。(2)NOS抑制剂L-NAME阻断了isoprenaline产生的血管舒张作用。(3)β₁-AR阻滞剂CGP20712A不能阻断isoprenaline产生的外围血管舒张作用,但β₂-AR阻滞剂ICI118551能阻断isoprenaline产生的外周血管舒张作用。结论:Isoprenaline引起兔股动脉舒张通过激活NOS介导,涉及的β受体亚型为β₂受体。     

Effects of carbon dioxide on preoptic thermosensitive neurons in vitro

Effects of carbon dioxide (CO₂) on the firing rates of preoptic thermosensitive neurons were examined in rat brain slice preparations. The perfusing medium was saturated with gas mixtures consisting of 90% O₂ and one of various concentrations (5%, 6.3%, 7.5%, and 10%) of CO₂ balanced with N₂. The medium containing 5% CO₂ was used as control. Most preoptic neurons were inhibited during application of a high CO₂ medium. An excitatory effect of CO₂ on a small number of neurons was also significant, although this was weak and transient compared to the inhibitory effect. Thermosensitivities of the neurons did not correlate with their CO₂ sensitivities. The influence of CO₂ tended to be more evident at higher temperatures. We conclude that the direct effect of CO₂ on PO thermosensitive neurons as well as on thermally insensitive neurons is mainly inhibitory.