蓝斑核注射乙酰胆碱对大鼠蓝斑核痛反应神经元电活动的影响

[摘要] 目的 观察蓝斑核（LC）注射乙酰胆碱(ACh)后,蓝斑核（LC）中痛反应神经元的放电变化,研究ACh与LC在痛觉信息通路中的作用。 方法 以电脉冲刺激坐骨神经作为伤害性刺激,用玻璃微电极引导LC中痛反应神经元的电变化。结果 ① LC内注入ACh能够使大鼠LC中痛兴奋神经元（PEN）痛诱发放电频率增加、潜伏期缩短;痛抑制神经元（PIN）痛诱发放电频率减少、完全抑制时程延长;② LC内注入ACh 的M受体拮抗剂阿托品能够阻断ACh的上述效应。结论 ACh可使正常大鼠LC中痛反应神经元对伤害性刺激的反应增强,表现为致痛效应;揭示了ACh和LC在痛觉调制中具有非常重要的作用。     

吗啡成瘾对大鼠伏隔核神经元自发放电的影响

目的 研究吗啡成瘾对大鼠伏隔核电生理的影响及静脉吗啡注射对吗啡成瘾大鼠伏隔核神经元自发放电的影响探讨伏隔核在吗啡成瘾过程中的作用.方法 通过连续14日递增腹腔吗啡注射,建立急性大鼠吗啡成瘾模型,通过玻璃微电极记录吗啡依赖大鼠伏隔核单细胞细胞外放电,观察吗啡成瘾及静脉注射吗啡对大鼠伏隔核神经元放电的影响.结果 与生理盐水组相比,吗啡依赖组大鼠伏隔核神经元单位自发放电的频率分布组间差异显著(P<0.05),放电形式无明显差异.吗啡依赖大鼠伏隔核神经元放电频率静脉注射吗啡前为14.40±4.92Hz,静脉注射吗啡后降为4.10±2.65Hz.结论 吗啡成瘾对大鼠伏隔核神经元自发放电有影响,吗啡可以显著抑制吗啡成瘾大鼠的伏隔核神经元放电,伏隔核在吗啡成瘾过程具有重要作用.     

谷氨酸对丘脑束旁核痛兴奋神经元放电的影响

目的：观察脑室注射谷氨酸（Glu)对大鼠丘脑束旁核（PF）痛兴奋神经元（PEN）电变化的影响。方法：以电脉冲刺激右侧坐骨神经作为伤害性痛刺激，用玻璃微电极细胞外记录神经元放电的变化。结果：（1）伤害性刺激使大鼠丘脑PF的PEN诱发放电频率增加；（2）脑室注射Glu(1.5μg/10μl）加强PEN的电活动，使PEN放电频率的净增值增加，潜伏期缩短；（3）这种作用可被Glu的NMDA受体拮抗剂MK－801（0．17μg/0.5μl)所阻断。结论：Glu在中枢痛沉调制中可能起兴奋作用，而NMDA受体参与介导中枢伤害性信息的传递过程。     

脑室注射吗啡对大鼠尾核神经元放电和甩尾反射的影响

浅麻醉Ｗｉｓｔａｒ大鼠４９只，用辐射热照尾部作为伤害性刺激，以痛兴奋神经元（ｐａｉｎｅｘｃｉｔａｔｉｏｎｎｅｕｏｎｓＰＥＮ）诱发放电频率减少，痛抑制神经抑（ｐａｉｎｉｎｈｉｂｉｔｉｏｎｎｅｕｒｏｎｓ，ＰＩＮ）诱发放电频率增加和甩尾反射潜伏期（ｔａｉｌｆｌｉｃｋｌａｔｅｎｃｙＴＦＬ）延长为镇痛效应，观察脑室注射不同剂量吗啡对尾核中ＰＥＮ，ＰＩＮ及ＴＦＬ的同时影响，表明，脑室注射５０μｇ／１０μｌ吗啡     

GABA对大鼠伏隔核痛反应神经元电活动的影响

目的在50只成年Wister大鼠上，观察了侧脑室(icv)注射GABA(γ-氨基丁酸)后，伏隔核(NAc)痛反应神经元放电的变化和荷包牡丹碱(Bic)对GABA作用的阻断效应，从而进一步研究GABA与NAc在痛觉调制中的作用。方法采用icy注射，电脉冲强直刺激坐骨神经作为伤害性痛刺激，玻璃微电极细胞外记录痛反应神经元放电的变化。结果(1)icv注入GABA能够使正常大鼠NAc中痛兴奋神经元(PEN)痛诱发放电频率减少、潜伏期延长，而使痛抑制神经元(PIN)痛诱发放电频率增加、诱发放电完全抑制时程缩短；(2)icv注入GABAA受体拮抗剂Bic能够阻断GABA的上述效应。结论(1)外源性GABA可使正常大鼠NAc中痛反应神经元对伤害性刺激的反应减弱，表现为镇痛效应；(2)GABA的这种镇痛作用主要是通过GABAA受体介导的。该结果揭示，GABA和NAc在痛觉调制中具有非常重要的作用。     

多巴胺对正常和吗啡成瘾大鼠疼痛相关电活动的不同作用

目的研究多巴胺对正常大鼠和吗啡成瘾大鼠中枢的伤害性刺激的传递的影响。方法在给予坐骨神经伤害性刺激后,记录中枢痛兴奋神经元的电活动,观察多巴胺对正常大鼠和吗啡成瘾大鼠中枢痛兴奋神经元电活动的影响。结果正常大鼠中,多巴胺使尾核痛兴奋神经元的痛诱发放电潜伏期缩短,说明多巴胺可使正常大鼠尾核痛兴奋神经元的活动增强,多巴胺受体拮抗剂氟哌利多可以阻断这种作用。吗啡大鼠中,多巴胺使尾核痛兴奋神经元的痛诱发放电潜伏期延长,说明多巴胺可使吗啡大鼠尾核痛兴奋神经元的活动减弱。结论脑室注射多巴胺后,正常大鼠和吗啡成瘾大鼠的尾核对痛刺激的反应存在着差异。     

大鼠丘脑束旁核痛反应神经元放电与甩尾痛反应的联合观察

本实验以辐射热照射大鼠尾部做为伤害性刺激，可同时引起丘脑束旁核中痛兴奋神经元（painexcitatoryneurons，PEN）放电增加，痛抑制神经元（paininhibitoryneurons，PIN）M电减少和甩尾反射．放电变化发生在先，甩尾反射发生在后，束旁核中PEN和PIN放电变化与甩尾反射呈显著正相关．电针“足三里”可使PEN放电频率减少，PIN的抑制时程缩短，以及甩用反射潜伏期延长．在中枢神经元放电和整体反射水平上同时呈现出镇痛效应。     

痛刺激后大鼠三叉神经尾侧亚核星形细胞和神经元相互关系的电镜观察

目的：观察大鼠上唇皮下注射福尔马林后，三叉神经尾侧亚核（Sp5C)内反应性星形细胞和神经元之间相互关系的超微结构。方法：用DAB染色的抗胶质原纤维酸性蛋白（GFAP）、抗connexin43(Cx43）和金颗粒标记抗Cx32双标记免疫电镜方法。结果：电镜下观察到Sp5C内反应性星形细胞和神经元之间存在4种联系结构：第一种是突触样结构；第二种是三种成分的突触复合体，第三种是缝隙连接；第四种是由Cx32和Cx43构成的异源性缝隙连接（HGJ）。HGJ表现为两侧膜增厚，Cx43阳性物质和Cx32阳性金颗粒分别位于星形细胞和神经元一侧，痛刺激后HGJ数明明显增加。结论：神经元和星形细胞之间有多种信息通道，HGJ可能是一种快速，适应性信息通道。Sp5C星形细胞可能通过HGJ调节神经元的活动，共同参与中枢神经系统对刺激反应的调节。     

谷氨酸对抗吗啡对丘脑束旁核痛反应神经元放电的影响

目的 研究脑室注射谷氨酸(Glu)对吗啡引起的大鼠两侧丘脑束旁核痛反应神经元电活动的影响。方法 以电脉冲刺激右侧坐骨神经作为伤害性刺激，同时用两根玻璃微电极细胞外记录两侧丘脑束旁核神经元的放电。结果 (1)腹腔注射吗啡(10mg／kg)可抑制痛兴奋神经元(PEN)和加强痛抑制神经元(PIN)的电活动；(2)脑室注射Glu(1．5μg／10μl)能对抗吗啡引起PEN放电的抑制作用和PIN电活动的加强作用；(3)Glu可同时对抗吗啡所引起束旁核中PEN和PIN的电变化。结论 Glu对吗啡引起的镇痛效应有明显的对抗作用，提示Glu在中枢伤害性信息整合方面发挥重要作用。     

Effects of electrical stimulation on acetylcholine synthesis in cat caudate nucleus

The concentration of endogenous- and deuterium-labeled acetylcholine (ACh) in the cat caudate nucleus was determined after stimulation of either the substantia nigra or the precruciate cortex. In this procedure the caudate nucleus is exposed surgically, and a coring device is used to obtain biopsy specimens which are immediately frozen in liquid nitrogen. Samples are collected at rest, 5 min after stimulation, and again 5 min after a resting period. An infusion of 2H9-choline is maintained during these manipulations to provide a label for ACh synthesis. Electrical stimulation of the substantia nigra, which increases the release of dopamine, produced a decrease in endogenous ACh and the newly synthesized deuterium-labeled ACh. Stimulation of the precruciate cortex produced no significant effect on the levels or synthesis of ACh, but attenuated the effect of subsequent nigral stimulation. These preliminary results indicate that stimulation of the substantia nigra has a net excitatory effect on ACh synthesis in the caudate. This stimulation apparently is modulated by input from the cortex.     

Effects of nerve growth factor on behavioral recovery following caudate nucleus lesions in rats

Rats with bilateral lesions of the caudate nucleus received intracaudate injections of either nerve growth factor protein (NGF) or inert buffer immediately following surgery. NGF-treated animals demonstrated a faster recovery of normal appetitive behavior and perseverated less than their buffer-treated counterparts on a spatial reversal task, but both groups were impaired relative to sham controls on acquisition of an active avoidance response. Glia to neuron ratios were significantly increased in both lesion groups when compared with sham controls. However, this increase was less in the NGF-treated animals than in the buffer-treated animals. NGF treatment had no effect on steady-state caudate dopamine levels, measured six months after surgery.     

Encoding of social state information by neuronal activities in the macaque caudate nucleus

Social animals adjust their behavior according to social relationships and momentary circumstances. Dominant–submissive relationships modulate, but do not completely determine, their competitive behaviors. For example, a submissive monkey's decision to retrieve food depends not only on the presence of dominant partners but also on their observed behavior. Thus, behavioral expression requires a dynamic evaluation of reward outcome and momentary social states. The neural mechanisms underlying this evaluation remain elusive. The caudate nucleus (CN) plays a pivotal role in representing reward expectation and translating it into action selection. To investigate whether their activities encode social state information, we recorded from CN neurons in monkeys while they performed a competitive food-grab task against a dominant competitor. We found two groups of CN neurons: one primarily responded to reward outcome, while the other primarily tracked the monkey's social state. These social state-dependent neurons showed greater activity when the monkeys freely retrieved food without active challenges from the competitor and reduced activity when the monkeys were in a submissive state due to the competitor's active behavior. These results indicate that different neuronal activities in the CN encode social state information and reward-related information, which may contribute to adjusting competitive behavior in dynamic social contexts.     

大鼠尾状核注射凝固自体动脉血脑出血模型

目的用自体血注射法复制出容量稳定、形状规则的脑血肿仍较困难,主要原因为难以控制针道返流。作者采用立体定向注射法向大鼠尾状核内注射50μl凝固自体动脉血,改进了大鼠脑出血模型,有效控制了血液沿针道返流。方法用立体定向仪将24G静脉留置针进针至尾状核中心并固定在颅骨上,股动脉抽血后立即注入更换了针头的50μl微量注射器内,静置5min使之充分凝固。将凝固血快速注入尾状核内(注射速度20μl/min)。结果凝固血注射组所有大鼠尾状核内均可见血肿形成。血肿局限在尾状核内,形态规则,呈椭圆形,占位效应明显,血肿平均容量18.02±5.48μl。结论该模型与临床脑出血相似,成本低,操作简单,血肿容量稳定、形状规则,重复性好。     

Disruption of the conditioned emotional response by caudate nucleus stimulation

The effectiveness of two forms of caudate nuclear stimulation in disrupting the development of a conditioned emotional response (CER) in rats was investigated. When a 5-sec train of 2/sec light flashes was used as a conditioned stimulus (CS), single pulse caudate stimulation delivered 100 msec after each light-flash effectively retarded acquisition of the CER. Posttrial caudate stimulation (delivered after the CS—US pairing) was less effective. The differential effectiveness of these two forms of stimulation in disrupting acquisition processes was most clearly seen during extinction of the CER. The group which received caudate stimulation during the CS extinguished faster than the group receiving caudate stimulation after the CS—US pairing. A nonstimulated control group was the fastest to acquire, and the slowest to extinguish the CER.     

Effects of feedback caudate nucleus stimulation on spontaneous fast amygdaloid spindles and drive

Experiments with single and repetitive stimulation of the head of the caudate nucleus (4–10 V, 0.3 msec) triggered by occurrence of fast amygdaloid spindles (35 c/s, 50 μV, 0.5 sec) were performed in six animals with chronically implanted cerebral electrodes. In conjunction with the anterior cortical recruiting response the stimulation increased the incidence of amygdaloid fast spindles and decreased the incidence of hippocampal theta activity and of searching eye movements. The associative training failed, however, to significantly modify in the background EEG, the mean incidence of the fast amygdaloid spindles or the rate of the sensorimotor rhythm of 12–18 c/s. Its only effect (after long repetition) was a displacement to the right of the regression line of the incidence of the two rhythms and a slight alteration in the slope. The possibility of activating the caudate nucleus inhibitory effects through the amygdala during internal inhibition phenomena is discussed.     

Ultrastructural alterations in caudate nucleus in aged cats

These studies provide information on the changes in the ultrastructure in the caudate nucleus of aged cats. The major findings was that there was a decrease in the density of synapses in caudate neuropil. This decrease occurred in animals after 3 years of age and remained relatively constant in older animals. In conjunction with this change a population of unusually long synapses also occurred. These larger synaptic appositions were associated with enlarged spine heads. The caudate also showed a number of qualitative ultrastructural alterations. Many neurons contained accumulations of lipofuscin or lipopigment granules in aged animals. These inclusions occurred in both soma and dendrites of neurons and all types of glial cells. A unique configuration of collapsed agranular cisterns also was observed in aged animals. The present results indicate that decreases in synaptic density may by one morphological event underlying functional alterations observed in caudate neurons in aged cats.     

多巴胺对正常和吗啡成瘾大鼠疼痛相关电活动的不同作用(英文)

目的研究多巴胺对正常大鼠和吗啡成瘾大鼠中枢的伤害性刺激的传递的影响。方法在给予坐骨神经伤害性刺激后,记录中枢痛兴奋神经元的电活动,观察多巴胺对正常大鼠和吗啡成瘾大鼠中枢痛兴奋神经元电活动的影响。结果正常大鼠中,多巴胺使尾核痛兴奋神经元的痛诱发放电潜伏期缩短,说明多巴胺可使正常大鼠尾核痛兴奋神经元的活动增强,多巴胺受体拮抗剂氟哌利多可以阻断这种作用。吗啡大鼠中,多巴胺使尾核痛兴奋神经元的痛诱发放电潜伏期延长,说明多巴胺可使吗啡大鼠尾核痛兴奋神经元的活动减弱。结论脑室注射多巴胺后,正常大鼠和吗啡成瘾大鼠的尾核对痛刺激的反应存在着差异。     

The role of the nucleus raphe pontis and the caudate nucleus in alfentanil rigidity in the rat

Attempts to eliminate or reduce the rigidity with high-dose narcotic anesthesia in the operating room have been only partially successful. Previous investigations of opioid receptor sites mediating this rigidity have implicated two central regions: the nucleus raphe pontis (NRP) within the reticular formation and the caudate nucleus (CN) within the basal ganglia. The present study used systematically administered alfentanil (ALF), a potent, short-acting fentanyl analog, and intracerebrally infused methylnaloxonium (MN), a quaternary derivative of naloxone, to elucidate further the functional role of the NRP and CN in rigidity. ALF (0.5 mg/kg s.c.) produced a reliable model of rigidity, as documented by gastrocnemius electromyography. The onset of this rigidity was within 60 s of ALF administration, with a total duration of approximately 40–50 min. Intracerebroventricular (i.c.v.) injections of 2.0 or 4.0 μg of MN 15 min prior to ALF treatment prevented rigidity, while 0.125 or 0.5 μg had no significant effect on rigidity. MN injected directly into the NRP at doses as low as 0.125 μg significantly antagonized ALF-induced rigidity, while injections of MN into the caudate nucleus at doses as high as 4.0 μg failed to antagonize ALF-induced rigidity. These observations demonstrate that injection of MN into the NRP is at least 16-fold more effective in blocking ALF-induced rigidity than MN injected into the ventricle and, more importantly, at least 32-fold more effective than MN injected into the CN. The results suggest that the NRP may be an important site for the neural control of muscular rigidity associated with high-dose narcotic administration.