心外膜应用腺苷时c—fos在脊髓延髓和丘脑中的表达

在１２只切断两侧缓冲神经和迷走神经的麻醉大鼠,观察了心外膜应用腺苷对脊髓,延髓和丘脑ｃ－ｆｏｓ原部基因表达的影响。结果显示：心外膜应用腺苷组大鼠,动脉血压和心率无明显变化;脊髓Ｔ３节段背角,延髓巨细胞旁外侧核以及丘脑的腹后外侧核,后核,中央外侧核和束旁核等部位Ｆｏｓ蛋白样免疫阳性反应神经元显著增加;而在溶剂对照组大鼠,仅见少数ＦＬＩ细胞。     

Catecholamine-containing sympathetic spinal neurons innervating the feline heart

The present study determined that a population "nonclassical" sympathetic neurons in cats spinal cord contains catecholamines. They are localized in the central, dorsomedial, and lateral regions of the ventral horn of T1-T5 segments of the spinal cord. Electrophysiological study indicated that axonal conduction velocity is 7.3 +/- 0.5 m/s (ranging from 3.6 to 17.2 m/s). Possible functional roles of catecholamine-containing neurons of spinal cord include involvement in sympathetic control of cardiac cycle duration.     

Laminar distribution of sources of ascending spinocerebral fiber systems in the cat spinal cord

The location of labeled neurons that are sources of ascending crossed and uncrossed supraspinal fiber systems was studied in the laminae of gray matter of the spinal cord in 18 cats by the retrograde axonal transport of horseradish peroxidase method. Neurons in the lateral zones of the dorsal horn were shown to make direct, and cells in neighboring regions indirect (through relay nuclei of the dorsal columns) connections with the contralateral thalamus. In the lower segments of the spinal cord sources of crossed spinoreticular and spinothalamic fiber systems are located in the medial regions of the ventral horn and lateral zones of the lateral basilar region. Some large neurons in the motor nuclei were shown to send their axons into the lateral reticular nucleus of the medulla. On the basis of the results a scheme of the laminar organization of sources of ascending fiber systems in the cat spinal cord is constructed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 11, No. 5, pp. 451–459, September–October, 1979.     

脊髓自噬功能激活与大鼠2型糖尿病神经病理性疼痛的关系

目的：探讨脊髓自噬功能与大鼠2型糖尿病神经病理性疼痛（DNP）的关系。方法：雄性SD大鼠（42只）高糖高脂饲养8周,腹腔单次注射链脲佐菌素（STZ）制备大鼠2型糖尿病模型。两周后检测机械缩足阈值（MWT）和热缩足潜伏期（TWL）,降至基础值80%以下者为2型糖尿病神经病理性疼痛大鼠,记为DNP组（24只）;未降至基础值80%以下者为2型糖尿病无神经病理性疼痛大鼠,记为DA组（18只）。另取18只大鼠为对照（control,C）组,普通饲料喂养。于确定DA与DNP分组后的第3、7和14天,测定机械缩足阈值（MWT）和热缩足潜伏期（TWL）,并在行为学检测结束后各组随机取6只大鼠处死,取L4~L6脊髓膨大,采用Western blot法检测自噬特异性蛋白微管相关蛋白1（Beclin-1）、微管相关蛋白1轻链3（LC3）和P62的表达。另取6只7 d DNP组大鼠采用免疫荧光双染法检测脊髓背角P62与小胶质细胞、星形胶质细胞、神经元的共表达情况。结果：连续8周喂养高糖高脂饲料的SD大鼠的血浆胰岛素水平升高,胰岛素敏感指数下调,表明出现胰岛素抵抗;在腹腔注射STZ后,血糖升高达到2型糖尿病诊断标准（≥16.7 mmol/L）;与C组、DA组比较,DNP组大鼠在第3、7和14天时MWT降低,TWL缩短,并且脊髓背角LC3-Ⅱ、Beclin-1表达上调,P62表达下降（P<0.05）。免疫荧光双染色显示,P62在脊髓背角表达,主要与神经元共存,少量与小胶质细胞共存,几乎不与星形胶质细胞共表达。结论：2型糖尿病神经病理性疼痛大鼠脊髓LC3-Ⅱ、Beclin-1和P62表达的改变提示脊髓自噬功能激活;脊髓背角中神经元自噬激活在2型糖尿病大鼠DNP的发生和发展起着关键作用。     

Distribution of glycine/GABA neurons in the ventromedial medulla with descending spinal projections and evidence for an ascending glycine/GABA projection

The ventromedial medulla (VM), subdivided in a rostral (RVM) and a caudal (CVM) part, has a powerful influence on the spinal cord. In this study, we have identified the distribution of glycine and GABA containing neurons in the VM with projections to the cervical spinal cord, the lumbar dorsal horn, and the lumbar ventral horn. For this purpose, we have combined retrograde tracing using fluorescent microspheres with fluorescent in situ hybridization (FISH) for glycine transporter 2 (GlyT2) and GAD67 mRNAs to identify glycinergic and/or GABAergic (Gly/GABA) neurons. Since the results obtained with FISH for GlyT2, GAD67, or GlyT2 + GAD67 mRNAs were not significantly different, we concluded that glycine and GABA coexisted in the various projection neurons. After injections in the cervical cord, we found that 29% ± 1 (SEM) of the retrogradely labeled neurons in the VM were Gly/GABA (RVM: 43%; CVM: 21%). After lumbar dorsal horn injections 31% ± 3 of the VM neurons were Gly/GABA (RVM: 45%; CVM: 12%), and after lumbar ventral horn injections 25% ± 2 were Gly/GABA (RVM: 35%; CVM: 17%). In addition, we have identified a novel ascending Gly/GABA pathway originating from neurons in the area around the central canal (CC) throughout the spinal cord and projecting to the RVM, emphasizing the interaction between the ventromedial medulla and the spinal cord. The present study has now firmly established that GABA and glycine are present in many VM neurons that project to the spinal cord. These neurons strongly influence spinal processing, most notably the inhibition of nociceptive transmission.     

The glutamatergic nature of TRPV1-expressing neurons in the spinal dorsal horn

The transient receptor potential vanilloid receptor 1 (TRPV1) is expressed on primary afferent terminals and spinal dorsal horn neurons. However, the neurochemical phenotypes and functions of TRPV1-expressing post-synaptic neurons in the spinal cord are not clear. In this study, we tested the hypothesis that TRPV1-expressing dorsal horn neurons are glutamatergic. Immunocytochemical labeling revealed that TRPV1 and vesicular glutamate transporter-2 were colocalized in dorsal horn neurons and their terminals in the rat spinal cord. Resiniferatoxin (RTX) treatment or dorsal rhizotomy ablated TRPV1-expressing primary afferents but did not affect TRPV1- and vesicular glutamate transporter-2-expressing dorsal horn neurons. Capsaicin significantly increased the frequency of glutamatergic spontaneous excitatory post-synaptic currents and miniature excitatory post-synaptic currents in almost all the lamina II neurons tested in control rats. In RTX-treated or dorsal rhizotomized rats, capsaicin still increased the frequency of spontaneous excitatory post-synaptic currents and miniature excitatory post-synaptic currents in the majority of neurons examined, and this effect was abolished by a TRPV1 blocker or by non-NMDA receptor antagonist. In RTX-treated or in dorsal rhizotomized rats, capsaicin also produced an inward current in a subpopulation of lamina II neurons. However, capsaicin had no effect on GABAergic and glycinergic spontaneous inhibitory post-synaptic currents of lamina II neurons in RTX-treated or dorsal rhizotomized rats. Collectively, our study provides new histological and functional evidence that TRPV1-expressing dorsal horn neurons in the spinal cord are glutamatergic and that they mediate excitatory synaptic transmission. This finding is important to our understanding of the circuitry and phenotypes of intrinsic dorsal horn neurons in the spinal cord.     

Responses of spinohypothalamic tract neurons in the thoracic spinal cord of rats to somatic stimuli and to graded distention of the bile duct

Anatomical studies indicate that a relatively large percentage of spinohypothalamic tract (SHT) neurons are located within thoracic spinal segments. The aim of this study was to characterize the responses of SHT neurons in these segments of rats to innocuous and noxious stimulation of the skin and of a visceral structure, the bile duct. In addition, we attempted to determine the trajectories of the axons of the examined neurons within the diencephalon and brainstem. Fifty-three SHT neurons were recorded within segments T8-T13 in urethane anesthetized rats. Each cell was antidromically activated using current pulses < or = 30 microA delivered from the tip of an electrode located within the contralateral hypothalamus. The recording points were located in the superficial dorsal horn (9) and deep dorsal horn (44). All examined SHT neurons had receptive fields on the posterior thorax and anterior and ventral abdomen of the ipsilateral side. Ninety percent of the 41 SHT neurons responded exclusively (13) or preferentially (24) to noxious cutaneous stimuli. Thirteen of 27 (48%) examined units were activated by forceful distention of the bile duct. Response thresholds ranged from 30 to 40 mmHg. Responses incremented as pressures were increased to 50-80 mmHg. The axons of 22 of 28 (79%) examined SHT neurons appeared to cross the midline within the hypothalamus and terminate in the ipsilateral hypothalamus, thalamus or midbrain. The results indicate that SHT neurons in thoracic spinal cord of rats are capable of conveying somatic and visceral nociceptive information from the bile duct directly to targets at various levels of the brain bilaterally.     

氯胺酮对单足致炎大鼠脊髓背角神经元活动的影响

在大鼠脊髓背角用细胞外记录技术共记录到３２个单位。角叉菜胶一侧足底注射致炎后,电刺激该侧足底内外侧神经激动其中Ａ、Ｃ纤维时,脊髓背角神经元诱发放电数均显著增加;静脉注射ＮＭＤＡ受体拮抗剂氯胺酮后,Ａ、Ｃ纤维刺激诱发的放电反应均显著下降甚至消失。致炎后脊髓背角深层单位出现Ｗｉｎｄｕｐ现象,静脉注射氯胺酮后该现象减轻消失。结果提示：角叉菜胶致炎导致脊髓背角神经元兴奋性升高和Ｗｉｎｄｕｐ;ＮＭＤＡ受体参     

A trigeminoreticular pathway: implications in pain

Neurons in the caudalmost ventrolateral medulla (cmVLM) respond to noxious stimulation. We previously have shown most efferent projections from this locus project to areas implicated either in the processing or modulation of pain. Here we show the cmVLM of the rat receives projections from superficial laminae of the medullary dorsal horn (MDH) and has neurons activated with capsaicin injections into the temporalis muscle. Injections of either biotinylated dextran amine (BDA) into the MDH or fluorogold (FG)/fluorescent microbeads into the cmVLM showed projections from lamina I and II of the MDH to the cmVLM. Morphometric analysis showed the retrogradely-labeled neurons were small (area 88.7 μm(2)±3.4) and mostly fusiform in shape. Injections (20-50 μl) of 0.5% capsaicin into the temporalis muscle and subsequent immunohistochemistry for c-Fos showed nuclei labeled in the dorsomedial trigeminocervical complex (TCC), the cmVLM, the lateral medulla, and the internal lateral subnucleus of the parabrachial complex (PBil). Additional labeling with c-Fos was seen in the subnucleus interpolaris of the spinal trigeminal nucleus, the rostral ventrolateral medulla, the superior salivatory nucleus, the rostral ventromedial medulla, and the A1, A5, A7 and subcoeruleus catecholamine areas. Injections of FG into the PBil produced robust label in the lateral medulla and cmVLM while injections of BDA into the lateral medulla showed projections to the PBil. Immunohistochemical experiments to antibodies against substance P, the substance P receptor (NK1), calcitonin gene regulating peptide, leucine enkephalin, VRL1 (TPRV2) receptors and neuropeptide Y showed that these peptides/receptors densely stained the cmVLM. We suggest the MDH- cmVLM projection is important for pain from head and neck areas. We offer a potential new pathway for regulating deep pain via the neurons of the TCC, the cmVLM, the lateral medulla, and the PBil and propose these areas compose a trigeminoreticular pathway, possibly the trigeminal homologue of the spinoreticulothalamic pathway.     

Interferon-γ receptors are expressed at synapses in the rat superficial dorsal horn and lateral spinal nucleus

Summary Interferon-γ can facilitate the spinal nociceptive flexor reflex and elicit neuropathic pain-related behavior in rats and mice. Immunoreactivity for the interferon-γ receptor (IFN-γR) occurs in the superficial layers of the dorsal horn and the lateral spinal nucleus in the rat and mouse spinal cord, as well as in subsets of neurons in the dorsal root ganglia. The aim of the present study was to examine the cellular localization and origin of the IFN-γR in the spinal cord. As viewed by confocal microscopy, the immunopositivity for the IFN-γR was co-localized with that of the presynaptic marker synaptophysin and with neuronal nitric oxide synthase in the lateral spinal nucleus, whereas only a minor overlap with these molecules was observed in laminae I and II of the dorsal horn. There was no co-localization of the IFN-γR with markers for astrocytes and microglial cells. Ultrastructurally, the IFN-γR was found predominantly in axon terminals in the lateral spinal nucleus but also at postsynaptic sites in dendrites in laminae I and II. The IFN-γR expressed in neurons in dorsal root ganglia was transported in axons both centrally and peripherally. Hemisection of the spinal cord caused no reduction in immunolabelling of the IFN-γR in the dorsal horn or the lateral spinal nucleus. Since rhizotomy does not effect the immunolabelling in the lateral spinal nucleus, our observation indicates that the presynaptic receptors in this nucleus are derived from intrinsic neurons. The localization of the IFN-γR in the spinal cord differed from that of the AMPA glutamate receptor subunits 2 and 3 and the substance P receptor (NK1). Our results, showing localization of IFN-γR to pre- and postsynaptic sites in the dorsal horn and lateral spinal nucleus indicate that IFN-γ can modulate nociception at the spinal cord level.     

胃伤害性刺激诱导大鼠脑干星形胶质细胞GFAP蛋白表达及其与神经元的关系

研究大鼠在福尔马林诱发胃伤害性刺激时脑干内星形胶质细胞及神经元的变化。应用免疫组织化学三重标记法在脑原位切片同时显示脑干内Fos蛋白,胶质原纤维酸性蛋白（GFAP）,酪氨酸羟化酶（TH）的表达,结果显示：1、在福尔马林诱发胃伤害性刺激后,脑干胶质细胞GFAP表达阳性,并表现出明显的核团或亚核定位特点,在延髓内脏带（MVZ0,中缝大核（RMg),蓝斑（LC）,臂旁外侧核（LPB）,中缝背核（DR）,中脑导水管周围灰质腹外侧区（vlPAG),上丘中灰层（IngSC)等脑区有较多的Fos阳性细胞,而且Fos阳性表达的分布与上述GFAP阳性分布基本一致;2、MVZ,LC,DR,vlPAG等部位有大量Fos及TH双标阳性神经元,周围有密集的GFAP阳性细胞;3、随着刺激后存活时间的变化,GFAP与Fos阳性细胞的反应均经历逐渐升高后又渐降低直至消失的变化。结果表明：上述核团的神经元和星形胶质细胞可能同时参与了内脏痛及其调节过程。     

Localization of Endomorphin-2-Like Immunoreactivity in the Rat Medulla and Spinal Cord

Martin-Schild, S., J. E. Zadina, A. A. Gerall, S. Vigh and A. J. Kastin. Localization of endomorphin-2-like immunoreactivity in the rat medulla and spinal cord. Peptides 18(10) 1641–1649, 1997.—Endomorphin-1 (Tyr-Pro-Trp-Phe-NH₂) and endomorphin-2 (Tyr-Pro-Phe-Phe-NH₂) are endogenous ligands that have greater affinity and selectivity for the μ-opiate receptor than any other known mammalian peptide. A polyclonal antiserum, screened for specificity to endomorphin-2 by immunodot-blot assay and preabsorption controls, was used for localization of this peptide. Immunocytochemistry performed on the brainstem, spinal cord, and sensory ganglia of rats by the avidin–biotin–peroxidase method revealed a continuous dense aggregation of endomorphin-2-like immunoreactive varicose fibers in the superficial laminae of the dorsal horn of the medulla and spinal cord. Immunoreactive fibers were detected in the dorsal root as well as within the dorsal root ganglia. The results suggest that endomorphin-2 is synthesized in primary sensory neurons in ganglia, transported to the superficial dorsal horn, and released near neurons expressing μ receptors. Its distribution appears to represent a functional unit likely to be associated with modulation of nociceptive stimuli.     

Structure and localization of sympathetic neurons in the cat spinal cord

By the method of retrograde axonal transport of horseradish peroxidase (HP) structure and localization of sympathetic neurons sending axons to the cranial cervical ganglion (CCG) have been revealed ipsilaterally in the ventral horns and in 4 nuclei of the spinal cord: nucl ILp, nucl. ILf. nucl. IC, nucl. ICpe. Orientation of the neurons, their number, structure of the nuclei formed by them, degree of the CCG efferentation by the preganglionic fibres, which run from various nuclei, are different. In nucl. ILf two types of neurons have been revealed-triangle and spindle-shaped, they always orienting by their long axis in mediolateral direction. The greatest amount of HP-positive neurons are found in nucl. ILp. They form a well distinquished compact nucleus in the lateral horns. HP-labelled neurons in nucl. ILp are found at the level of segments T1-T8 with their maximal amount at the level of segments T1-T3. HP-positive neurons are detected in nucl. ILf beginning from the segment C8 up to the middle of T4, in nucl. IC-from the segment C8 up to T6, in nucl. ICpe-from the segment C8 up to T5, in the ventral horns-from the segment T1 up to T5. In rostocaudal direction from the segment C8 up to T8 the number of HP-positive neurons is decreasing, but the part of nucl. ILp neurons in the CCG efferentation, comparing to the neurons in other sympathetic structures of the spinal cord, is increasing.     

Water deprivation increases Fos immunoreactivity in PVN autonomic neurons with projections to the spinal cord and rostral ventrolateral medulla

The present study sought to determine whether water deprivation increases Fos immunoreactivity, a neuronal marker related to synaptic activation, in sympathetic-regulatory neurons of the hypothalamic paraventricular nucleus (PVN). Fluorogold (4%, 50 nl) and cholera toxin subunit B (0.25%, 20-30 nl) were microinjected into the spinal cord (T1-T3) and rostral ventrolateral medulla (RVLM), respectively. Rats were then deprived of water but not food for 48 h. Water deprivation significantly increased the number of Fos-positive nuclei throughout the dorsal, ventrolateral, and lateral parvocellular divisions of the PVN (water deprived, 215 +/- 23 cells; control, 45 +/- 7 cells, P < 0.01). Moreover, a significantly greater number of Fos-positive nuclei were localized in spinally projecting (11 +/- 3 vs. 2 +/- 1 cells, P < 0.025) and RVLM-projecting (45 +/- 7 vs. 7 +/- 1 cells, P < 0.025) neurons of the PVN in water-deprived vs. control rats, respectively. The majority of these double-labeled neurons was found in the ventrolateral and lateral parvocellular divisions of the ipsilateral PVN. Interestingly, a significantly greater percentage of RVLM-projecting PVN neurons were Fos positive compared with spinally projecting PVN neurons in the ventrolateral (25.8 +/- 0.7 vs. 8.0 +/- 1.5%, respectively, P < 0.01) and lateral (23.4 +/- 2.1 vs. 5.0 +/- 0.9%, respectively, P > 0.01) parvocellular divisions. In addition, we analyzed spinally projecting neurons of the RVLM and found a significantly greater percentage were Fos positive in water-deprived rats than in control rats (26 +/- 3 vs. 3 +/- 1%, respectively; P < 0.001). Collectively, the present findings indicate that water deprivation evokes a distinct cellular response in sympathetic-regulatory neurons of the PVN and RVLM.     

蛋白激酶C部分参与伤害性刺激在脊髓背角神经元中引起的c-fos蛋白的表达而可能不参与阿片受体对脊髓痛感受的调制

实验用免疫细胞化学技术观察了大鼠鞘内分别注入蛋白激酶(PKC)抑制剂Chelerythrine(Chel)、纳洛酮(Nal)、或二者同时注入后,由后脚掌注射福尔马林引起的脊髓腰膨大背角中c-fos蛋白样免疫活性(Fos-LI)神经元数目的改变。结果发现:(1)鞘内注入Chel可显著降低福尔马林注射侧脊髓背角中Fos-LI神经元的数目,同空白对照组(鞘内注入生理盐水或10％的DMSO)相比,降低60.3％(P<0.001):(2)鞘内注入Nal后,福尔马林注射侧背角中Fos-LI神经元显著增加,同对照组相比,增加46.0％(P<0.01),而以背角深层增加最为明显;(3)在鞘内同时注入Chel和Nal后,与单独注入Nal组相比,脊髓背角中Fos-LI神经元的数目显著降低(降低53.2％),此数值与上述单独注入Chel时引起Fos-LI神经元降低的百分率近似。结果提示:(1)PKC只参与脊髓背角中部分Fos-LI神经元中c-fos蛋白的表达;(2)PKC可能不参与背角中同时激活的μ-(以及部分δ-)阿片受体对脊髓伤害性感受的调制。     

Calcitonin gene-related peptide 8-37 inhibits the evoked discharge frequency of wide dynamic range neurons in dorsal horn of the spinal cord in rats.

The present study was performed to explore the effect of calcitonin gene-related peptide 8-37 (CGRP8-37) on the electrical stimulation-evoked discharge frequency of wide dynamic range (WDR) neurons in the dorsal horn of the spinal cord in rats. The discharge frequencies of WDR neurons were evoked by transdermic electrical stimulation applied on the ipsilateral hindpaw. CGRP8-37 was applied directly on the dorsal surface of the L3 to L5 spinal cord. After the administration of 3 nmol of CGRP8-37, the evoked discharge frequency of WDR neurons decreased significantly, an effect lasting more than 30 min. The results indicate that CGRP receptors play an important role in the transmission of presumed nociceptive information in the dorsal horn of the spinal cord.     

Characterization of the autonomic innervation of mammary gland in lactating rats studied by retrograde transynaptic virus labeling and immunohistochemistry

The aim of experiments was to characterize the neurons of the autonomic chain that innervates the nipple and the mammary gland of lactating rats using retrograde transynaptic virus labeling and neurotransmitter and neuropeptide immunohistochemistry. Two days after injection of green fluorescence protein labeled virus in two nipples and underlying mammary glands, labeling was observed in the ipsilateral paravertebral sympathetic trunk and the lateral horn. Three days after inoculation the labeling appeared in the brain stem and the hypothalamic paraventricular nucleus. Above the spinal cord the labeling was bilateral. A subpopulation of virus labeled cells in the paraventricular nuclei synthesized oxytocin. Labeled neurons in the lateral horn showed cholinergic immunoreactivity. These cholinergic neurons innervated the paravertebral ganglia where the virus labeled neurons were partially noradrenergic. The noradrenergic fibers in the mammary gland innervate the smooth muscle wall of vessels, but not the mammary gland in rats. The neurons in the lateral horn receive afferents from the brain stem, and paraventricular nucleus and these afferents are noradrenergic and oxytocinergic. New findings in our work: Some oxytocinergic fibers may descend to the neurons of the lateral horn which innervate noradrenergic neurons in the paravertebral sympathetic trunk, and in turn these noradrenergic neurons reach the vessels of the mammary gland.     

溴化乙锭诱导的短暂脱髓鞘增强PRV的逆行转导效率 *

目的 改进伪狂犬病病毒(Pseudorabies virus,PRV)的注射方法,通过溴化乙锭(ethidium bromide,EB)诱导的短暂脱髓鞘提高PRV的转导效率。方法 选用18只正常成年Wistar大鼠,随机分为肌肉组、NS组和EB组(n=6)。肌肉组将2μl滴度为2×10 ⁹的PRV工具病毒注射到胫骨前肌和腓肠肌上;NS组将2μl生理盐水(normal saline,NS)注射到坐骨神经上,1周后相同位置注射2μl滴度为2×10 ⁹的PRV;EB组将2μl 0.1%的EB注射到坐骨神经上,1周后相同位置注射2μl滴度为2×10 ⁹的PRV。大鼠注射PRV 5天后,灌流取材并制作冰冻切片,观察各级神经元的感染情况。 结果 EB组大鼠L4-L5脊髓前角神经元和背根神经节(DRG)、T8脊髓中间神经元、C4脊髓中间神经元、延髓、中脑、大脑皮层均有大量神经元被PRV标记。肌肉组和NS组各级神经元仅有少量被PRV标记。结论 EB诱导坐骨神经脱髓鞘后能够显著提高PRV的逆行转导效率。     

Role of calcitonin gene-related peptide and its antagonist on the evoked discharge frequency of wide dynamic range neurons in the dorsal horn of the spinal cord in rats.

The present study was performed to explore the effect of calcitonin gene-related peptide (CGRP) and its antagonist CGRP8-37 on the evoked discharge frequency of wide dynamic range (WDR) neurons in the dorsal horn of the spinal cord in rats. Recording was performed with a multibarrelled glass micropipette and the chemicals were delivered by iontophoresis. The discharge of WDR neurons was evoked by transdermic electrical stimulation applied on the ipsilateral hindpaw. (1) Iontophoretic application of CGRP at an ejection current of 100 nA increased the discharge frequency of WDR neurons significantly. (2) Iontophoretic application of CGRP8-37 at an ejection current of 80 or 160 nA induced significant decreases in the discharge frequency of WDR neurons, but not at 40 nA. (3) Iontophoretic application of CGRP8-37 not only antagonized the CGRP-induced increase in the evoked discharge frequency of WDR neurons but also induced a significant decrease in the evoked discharge frequency of WDR neurons compared to basal levels. The results indicate that CGRP and its receptors play a facilitary role on the transmission and/or modulation of nociceptive information in the dorsal horn of the spinal cord in rats.     

Neurons of the medulla oblongata and hypothalamus projecting on the sympathetic neurons of the ventral horn of the spinal cord]

Connections of the neurons of the spinal cord ventral horn with the structures, situating above have been investigated. After injection of uranyl acetate into the TIII segment of the spinal cord, labelled neurons are found in various reticular nuclei of the medulla oblongata. At the level of the roots of the XII pair of the cranial nerves they are revealed in the reticular paramedian, ventral, parvocellular and lateral nuclei. The formations mentioned participate in regulation of the cardio-vascular system. More rostral (2 and 4 mm relatively to the roots of the XII pair of the cranial nerves) the neurons are observed in the reticular giant cellular nucleus, in nuclei of the raphe and in the group of the P-substance reactive neurons. Besides, labelled neurons are revealed in the posterior, lateral fields and in the dorso- and ventromedial nuclei of the hypothalamus.