侧脑室注射后叶素、缩宫素及加压素对叫反应的影响

本实验以刺激“怒叫中枢”引起的叫反应为痛反应指标,观察侧脑室注射后叶素、缩宫素和加压素对叫反应的影响。结果表明,上述多肽对叫反应均有一定的压抑作用,其中,缩宫素对叫反应的压抑作用强,出现也快,持续时间久。后叶素的压抑作用除出现稍迟外,其余均与缩宫素同。加压素的压抑作用持续时间最短。侧脑室注射生理盐水对叫反应无明显影响。实验结果提示:电刺激视上核区域的镇痛效应可能与上述多肽的分泌和释放增加有关。     

侧脑室注射缩宫素、加压素和后叶素对清醒猫怒叫反应的影响

我们曾以刺激“怒叫中枢”引起的叫反应作为痛反应指标,在麻醉猫上观察到侧脑室注射下丘脑激素(缩宫素、加压素和后叶素)对叫反应有一定的抑制作用。为进一步探讨这些激素的作用,在清醒猫上进行类似的实验。在“怒叫中枢”及侧脑室分别植入刺激电极及注射套管。手术后10—15天,开始实验。用给药前的叫反应作为对照,与给药后不同时间的叫反应进行比较。在7只猫上进行的25次观察的结果表明:脑室注射这些激素对动物的叫反应和行为如怒、攻击、逃避等均有显著的抑制作用。有些动物在实验期间和实验后显得比较安静,甚至呈瞌睡状态。在这些激素中,缩宫素对叫反应的抑制作用出现早,作用强而持久,加压素的抑制作用除出现稍晚外,作用强度和持续时间均与缩宫素相似。后叶素作用出现虽早,但作用弱,持续时间也短。脑室注射生理盐水对动物的叫反应及行为均无明显影响。本实验的结果表明,下丘脑激素在清醒动物发挥的镇痛作用与急性实验相似,说明下丘脑视上核区域的镇痛效应很可能与这些激素的分泌和释放有关。     

刺激家兔腓深神经对颈动脉体化学感受性升压反射的调整作用

在麻醉、制动和人工通气的79只家兔上观察到,由颈动脉内注射氰化钠(NaCN)引起的颈动脉体化学感受性升压和肾交感放电增强反应(简称颈动脉体反应),在刺激腓深神经模拟电针“足三里”穴位时发生明显改变。此种改变与腓深神经刺激前颈动脉体反应的强度有关。在吸入气中加入CO_2或切断双侧颈迷走神经以提高心血管中枢活动水平时,颈动脉体反应增强,此时刺激腓深神经可使此反应减弱(P<0.01)。在迷走神经完整、增加潮气量使血液CO_2分压降低,使颈动脉体反应减弱时,刺激腓深神经可使颈动脉体反应增强(P<0.01)。上述结果表明,刺激腓深神经,对颈动脉体化学感受性心血管反应具有调整作用,这种作用与心血管中枢反应性密切相关。而后者又受到迷走神经传入冲动、PaCO_2水平和麻醉深度调制。     

家兔尾核头不同区域电刺激对痛反应的影响

电刺激家兔尾核头前区(A_4、A_5)能提高痛阈,刺激后区(A_2、A_3)能降低痛阈,两区的刺激均可不伴以可见的运动反应。内囊及胼胝体刺激一般虽可引起明显的运动反应,但痛阈变化不大。刺激前区痛反应压抑点与后区痛反应易化点所引起的痛阈变化和尾核刺激电流的对数呈直线回归关系。前者有明显的后效应,其大小与持续时间亦随刺激电流的增加而加大。刺激后区易化点没有明显的后效应。本文进一步肯定了作者在大白鼠上的实验结果,说明在生理情况下尾核头前区具有镇痛功能,激活它可使痛阈增加,后区的活动则与此相反,对痛反应有易化作用。     

电刺激大鼠中脑导水管周围灰质对针刺镇痛效应的影响

本工作以刺激大鼠尾部引起的甩尾和嘶叫作为痛反应。假手术组痛反应阈值稳定。电针和刺激中脑导水管周围灰质(PAG)均能引起痛阈显著提高。电针加刺激 PAG 所引起痛阈增加值大于分别给予两种刺激的痛阈增值之和。     

电刺激猕猴迷走神经中枢端对海马单位放电的影响

本文观察了用强电刺激猕猴颈迷走神经中枢端,对海马单位放电活动的影响。结果如下:(1)刺激迷走神经中枢端,海马单位放电频率,多数增加,部分减少,少数不变;侧脑室注射吗啡后,刺激迷走神经中枢端,增频反应的单位增多,减频反应的单位减少。(2)侧脑室注射纳洛酮,可明显拮抗吗啡的上述作用,使发生增频反应的单位减少,减频反应的单位增多。由此表明,迷走传入冲动可影响海马单位放电活动。并且提示,胆碱能纤维与海马脑啡肽能神经元之间存在着机能上的联系。     

大鼠尾部痛刺激后脊髓骶尾段一氧化氮合酶的变化

用ＮＡＤＰＨｄ（还原型辅酶Ⅱ）组织化学方法观察大鼠尾部电流致痛刺激后不同时间脊髓骶尾段ＮＯＳ（一氧化氮合酶）阳性神经元的反应变化。同时用ＦＯＳ的免疫组织化学观察痛刺激后ＦＯＳ的表达。本文观察显示：电流致痛刺激后１５ｍｉｎ脊髓骶尾段ＮＯＳ反应明显增强,持续相当长时间,至痛刺激后８小时才逐渐减弱,刺激后２４小时反应强度相当于对照动物。而ＦＯＳ免疫组织化学反应,在痛刺激后３０ｍｉｎ起有少数神经元胞核浅染。由于ＮＯ极易通过细胞膜以弥散方式作用于附近细胞,激活靶细胞的鸟苷酸环化酶,从而引起靶细胞一系列反应。提示ＮＯ可能影响ｃｆｏｓ的表达     

刺激迷走神經中樞端所引起的兔耳舒血管反应

刺激迷走神经中枢端所引起的血管反应舒缩不一,而其所引起的血压变化亦升降各异。Cobb等曾在猫和猴身上获得脑血管的舒张,Downman等曾在猫身上获得掌血管的收缩。刺激胸部器官所引起的全身血管的总反应多为舒张,其冲动系经迷走神经传人(Aviado等,Barer等,肖俊)。Harris等认为刺激迷走神经中枢端所引起的血压反应,在兔一般为降压,在狗因刺激的强弱而异,Domour等认为在鼠是降压     

不同频率电脉冲刺激大鼠下丘脑外侧区对丘脑束旁核痛放电的调制作用

下丘脑外侧区(LHA)是脑刺激镇痛的有效区之一。刺激该区能减弱大鼠的痛行为反应,并能抑制脑的痛放电活动,而损毁该区能导致动物的痛反应增强。丘脑束旁核(PF)有对伤害性刺激呈增频反应的痛兴奋单位和减频反应的痛抑制单位,合称痛相关单位。本实     

清醒状态下刺激鸟类中脑引起鸣叫及躯体运动等反应的观察

在麻醉或轻度麻醉状态下的急性突验中,刺激鸟类中脑引起鸣叫反应的研究,已由Bechterew,Popa 等先后用几种鸟进行了一定的工作;1957年作者曾在麻醉的鸡、鸭、鹅、家鸽、鸮、喜鹊、麻雀和金雀等中脑部位进行刺激,观察到在中脑网状结构处有支配与调节鸣叫反应的相应中枢。当该中枢接受刺激时,不仅引起惊恐性鸣叫,且引起呼吸、心跳、血压的变化,及一系列的肌体运动反应。     

Context-related vocalization rates of fallow bucks, Dama dama

We studied the short-term vocalization rates of fallow bucks to determine the primary recipients of the signal conveyed by these rates. We used the contexts in which groans occurred to investigate whether the signal represented an intrasexual threat or an intersexual advertisement. We found that fallow buck groaning rates were highly variable and that this variation was associated with the contexts of groaning. Groaning rates were higher during the rut than during the prerut, and also higher when males were with females than when they were with other males. Males with females groaned at higher rates when other vocal males were nearby. We identified a postcopulation call that consisted of the highest groaning rates that males produced. The presence of a harem did not contribute to the variation in groaning rates, except to a minor extent in postcopulation rates. Our findings suggest that the signal transmitted by short-term vocalization rates is primarily a threat aimed at other males. Copyright 1999 The Association for the Study of Animal Behaviour.     

电刺激大马蹄蝠听皮层对下丘神经元听觉敏感性的影响

实验在１２只大马蹄蝠上进行。用常规电生理学方法研究了电刺激听皮层对下丘２１２个神经元的听反应的影响,结果表明,有３２个神经元的听反应被抑制,１９个神经元的听反应褐易化。     

Functional organization of afferent inputs of neurons of the cat somatic cortex

Responses of cortical neurons in the posterior sigmoid gyrus to stimulation of two points of the ventro-posterolateral nucleus were investigated in cats immobilized with D-tubocurarine. Some neurons responding to stimulation of one point of this nucleus with a latent period of 2.5–4 msec, were activated by stimulation of the other point after 10 msec or longer. Conditioning stimulation of one point facilitated or inhibited the response to test stimulation of the other point. The facilitatory effect was usually exhibited if the response latency exceeded 5 msec. It is concluded that a cortical input neuron for some afferent fibers is activated by other similar afferent fibers only after intracortical relay. The system of "input" cortical neurons is thus not only a structural, but also to some extent a functional, concept; under certain conditions an incoming afferent volley activates them only polysynaptically.     

Role of substance P in regulating the feeding behavior and the avoidance reaction in the rabbit

Similar changes in feeding and avoidance reaction in spite of the way of substance P administration (30 mgk/kg intravenously or 14,8 nmol intraventricular) were found in rabbits with electrodes implanted in various limbic-midbrain structures. Feeding was found to be more sensitive to substance P administration, as it was shown by the decrease of excitability of the hypothalamic "feeding center" and abolishing of the inhibitory and facilitatory effects on this center from the dorsal hippocampus and the midbrain reticular formation, correspondingly. New cortical-subcortical integration under substance P was presented in new characteristics of EEG activity in neocortical areas, both background and in response to stimulation of various limbic-midbrain structures. Biochemical data let to suggest that at the neural level substance P led to destabilization of membrane structures in endoplasmatic reticulum and to redistribution of membrane-connected N-acetylneuramine acid which was directly involved in neurotransmission.     

Dissociation of the metabolic from the contractile response to muscarinic stimulation in the rabbit urinary bladder

The calcium dependence of contraction and NADH flurorescence was investigated in rabbit bladder stimulated with bethanechol or KCl. The absence of calcium in the bathing solution induced a rightward shift in the dose response to bethanechol for both contraction and NADH flurorescence. The contractile response was shifted to a greater degree than the fluorescence response and the maximal response to bethanechol was reduced by 80% for contraction but only 20% for NADH fluorescence. This rightward shift was also induced by the benzothiazepine calcium antagonist diltiazem (200 M) and again the contractile response was shifted significantly more than the fluorescence response. The combination of zero calcium and 200 M diltiazem virtually abolished contractions but only inhibited the NADH fluorescence by 65% at maximally effective bethanechol concentrations. Unlike the effect of diltiazem on the response to bethanechol, diltiazem (200 M) shifted both the contraction and fluorescence curves to the right equally in response to KCl stimulation. These results indicate that a metabolic response to muscarinic stimulation (decreased NADH) can occur in the absence of any observable contractile response. This metabolic response may be due to post receptor signal processing events. For KCl stimulation, the NADH response is probably secondary to and a result of the contractile response.Abbreviations ATP Adenosine Triphosphate - KCl Potassium Chloride - HPLC High Performance Liquid Chromatography - NADH reduced nicotinamide Adenine Dinucleotide - NAD Oxidized Nicotinamide Adenine Dinucleotide     

Factors involved in the intestinal feedback regulation of pancreatic enzyme secretion in the rat.

Further studies on the feedback regulation of pancreatic enzyme secretion by trypsin were conducted in conscious rats, surgically prepared so that pancreatic juice could be collected or returned. Suppression of enzyme secretion by trypsin as well as its stimulation by SBTI occurred only in the upper part of the small intestine, where the hormone CCK is known to be released. Over a limited range, trypsin suppression of pancreatic secretion was proportional to the dose of trypsin. Higher concentrations had no further effect, suggesting "saturation" of the intestine. Trypsin which had its active center blocked by DFP did not suppress enzyme output. These results supported the concept that only trypsin (or chymotrypsin) with an exposed active center suppressed pancreatic enzyme secretion in the rat by somehow suppressing the release of CCK from the intestinal cell. Presumably CCK is released from the intestine following "removal" of trypsin from the intestine either by diverting the juice or by feeding SBTI which binds the enzyme. All of the evidence supported the view that the effect of trypsin or SBTI on pancreatic secretion was mediated at the intestinal level and not in the blood as has been suggested.     

Role of Calcium Channels in Phytochrome-Mediated Regulation of Gravitropic Response

The effect of the inhibitors of calcium channels on red-light (R)-mediated inhibition of gravitropic bending was studied in excised wheat (Triticum aestivumL.) coleoptiles. The effect of a short R pulse (2 min) preceding the gravitropic stimulation was completely alleviated by a similar pulse of far-red light (FR), when the latter preceded the gravitropic stimulation and the delay between R and FR pulses did not exceed 20 min. Plant memory of the R pulse lasted up to 40 min. Neither R nor FR exerted any effect on the gravitropic reaction when applied after gravitropic stimulation. Treatment with 1 M of verapamil, LaCl₃, GdCl₃, or ruthenium red before the gravitropic stimulation prevented or released the R-exerted suppression of the gravitropic response (GR). The GR in coleoptiles is apparently regulated by the phytochrome system at the induction phase and involves calcium channels.     

Change in reactions of visual cortex neurons to light flash upon hypothalamic and reticular stimulation

The effect of electrical stimulation of the hypothalamic positive reinforcement zone (PRZ), the neutral hypothalamic zone (NZ), and the reticular formation (RF), of the midbrain on the impulse activity of single neurons of the visual cortex evoked by light flashes was studied in unanesthetized and uncurarized white rats. Poststimulus histograms of the neurons's responses were compared. Under the influence of stimulation the evoked activity of the neurons which responded to light changed in a majority of them (from 63% for the NZ to 82% for the RF). Qualitative differences were found in the effects of PRZ and RF stimulation. The effects of PRZ stimulation consisted in the invariability or in a decrease in the frequency of the neuron's discharge comprising the short-latent response, and an increase in the frequency of the discharges in the long-latent response ("positive-motivation" type). The effects of RF stimulation were manifested in intensification of the neuronal discharges in the short-latent and a decrease in the discharges in the long-latent response ("reticular" type). The responses of a considerable number of the neurons changed to the "combined" type. The data obtained indicates the different natures and mechanisms of the ascending activating effects caused by stimulation of the PRZ and the RF and which brings about positive nonspecific reinforcements. These effects, which are manifested differently in different periods of the neuron's working cycle cannot be explained by "energizing" or "tonus" concepts; their explanation must be sought for in informational (systemic) concepts.N. I. Grashchenkov Laboratory of Problems of Functional Control in the Human and Animal Organism, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 3, No. 4, pp. 359–368, July–August, 1971.     

The ultrastructure of the abdominal lymph nodes cortex in rats during primary and secondary immune response (a special reference to dendritic reticulum cells and interdigitating cells)

The stimulation of coeliac rat lymph nodes was performed by intraperitoneal injections of typhoid vaccine and was unique for the primary immune response and repeated after 6 weeks for the secondary response. The light and electron microscopic observations showed for the primary response, an early germinal center reaction, which might be accounted for by a background of continuous stimulation of the coeliac nodes, stemming from the digestive tract. The dendritic reticulum cells (DRC), considered typical for the B area, were located at the borderline between the germinal center and the mantle zone. Their cytoplasmic extensions penetrated the lymphocyte-lymphoblastic center, surrounding most of the germinal center cells. The marginal zone and the paracortex reacted as a whole, the interdigitating cells (IDC) being the dominant feature. An explanation would be that the marginal zone can be penetrated by T cells and connected IDCs, thus, the B and T areas seem to be largely interspersed. The results suggest that IDCs are cells of direct monocytic origin.     

The phase response of the cortical slow oscillation

Cortical slow oscillations occur in the mammalian brain during deep sleep and have been shown to contribute to memory consolidation, an effect that can be enhanced by electrical stimulation. As the precise underlying working mechanisms are not known it is desired to develop and analyze computational models of slow oscillations and to study the response to electrical stimuli. In this paper we employ the conductance based model of Compte et al. (J Neurophysiol 89:2707–2725, 2003) to study the effect of electrical stimulation. The population response to electrical stimulation depends on the timing of the stimulus with respect to the state of the slow oscillation. First, we reproduce the experimental results of electrical stimulation in ferret brain slices by Shu et al. (Nature 423:288–293, 2003) from the conductance based model. We then numerically obtain the phase response curve for the conductance based network model to quantify the network’s response to weak stimuli. Our results agree with experiments in vivo and in vitro that show that sensitivity to stimulation is weaker in the up than in the down state. However, we also find that within the up state stimulation leads to a shortening of the up state, or phase advance, whereas during the up–down transition a prolongation of up states is possible, resulting in a phase delay. Finally, we compute the phase response curve for the simple mean-field model by Ngo et al. (EPL Europhys Lett 89:68002, 2010) and find that the qualitative shape of the PRC is preserved, despite its different mechanism for the generation of slow oscillations.