Electrophysiological characteristics of identified kidney-related neurons in adult rat spinal cord slices

Whole-cell patch-clamp recordings were made from kidney-related neurons in the intermediolateral cell column (IML) in horizontal slices of thoracolumbar spinal cord from adult rats. Kidney-related neurons were identified in vitro subsequent to inoculation of the kidney with a fluorescent, retrograde, transynaptic pseudorabies viral label (i.e., PRV-152). Kidney-related neurons detected in the IML expressed choline acetyltransferase, characteristic of spinal preganglionic motor neurons. Their mean resting potential was −51 ± 4 mV and input resistance was 448 ± 39 MΩ. Both spontaneous inhibitory and excitatory post-synaptic currents (i.e., sIPSCs and sEPSCs) were observed in all neurons. The mean frequency for sEPSCs (3.1 ± 1 Hz) was approximately 2.5 times that for sIPSCs (1.4 ± 0.3 Hz). Application of the glycine and GABA_A receptor-linked Cl⁻ channel blocker, picrotoxin (100 μM) blocked sIPSCs, while the ionotropic glutamate receptor antagonist, kynurenic acid (1 mM) blocked all sEPSCs, indicating they were mediated by GABA/glycine and glutamate receptors, respectively. Thus, using PRV-152 labeling allowed whole-cell patch-clamp recording of neurons in the adult spinal cord, which were kidney-related. Excitatory glutamatergic input dominated synaptic responses in these cells, the membrane characteristics of which resembled those of immature IML neurons. Combined PRV-152 pre-labeling and whole-cell patch-clamp recordings may allow more effective analysis of synaptic plasticity seen in adult models of injury or chronic disease.     

Electrophysiological properties of sympathetic preganglionic neurons in the cat spinal cord in vitro

Intracellular recordings were obtained from sympathetic preganglionic neurons of the intermedio-lateral nucleus of the adult cat in slices of upper thoracic spinal cord maintained in vitro. The neurons were identified by their antidromic responses to stimulation of various ipsilateral sites. Sites from which antidromic responses could be evoked were the white ramus, the ventral root, the ventral root exit zone, the white matter between the latter and the outer edge of the tip of the ventral horn, the lateral edge of the ventral horn. Resting membrane potential was –61.3±1.6 mV (mean±SEM), input resistance 67.5±3.7 M, time constant 11.5±1.2 ms. The amplitude of the action potential generated by antidromic or direct stimulation was 77.4±2.3 mV. Threshold for direct spikes was 18.2±1.8 mV. The action potential had an average duration of 3.03±0.16 ms. It showed a prominent hump on the falling phase. The action potential had a tetrodotoxin (TTX)-sensitive and a TTX-resistant component. The latter was abolished by cobalt.Tetraethylammonium, cesium and barium prolonged the action potential duration which acquired a plateau-shape. A prolonged after-hyperpolarization (AHP) followed the sympathetic preganglionic neuron spike. Following a single spike, AHP duration and peak amplitude were 2.8±0.3 s and 16.6±0.7 mV, respectively. The AHP was abolished by cesium or barium, but enhanced by tetraethylammonium. An AHP followed the TTX-resistant spike. EPSPs and IPSPs could be generated by focal stimulation. The EPSP triggered spikes when threshold (15.0±2.0 mV) was reached. The slice of the thoracic spinal cord provides a useful experimental preparation for analysis of cellular properties and synaptic mechanisms of the sympathetic preganglionic neuron.     

Oxytocinergic innervation to the upper thoracic sympathetic preganglionic neurons in the rat

A combination of retrograde cell body labeling and immunohistochemistry was employed to elucidate how oxytocinergic fibers make contact with sympathetic preganglionic neurons (SPNs) in the rat spinal cord from T1 to T4. SPNs were labeled retrogradely using cholera toxin subunit B (CTb) or horseradish peroxidase-conjugated CTb. Oxytocin-immunoreactive (ir) fibers were found in the intermediate zone, including the sympathetic preganglionic subnuclei. In the central autonomie nucleus and the intercalated nucleus, brown-stained oxytocin-ir varicosities or terminals were frequently observed to stud black-stained dendrites of SPNs. Electron microscopical observations showed that oxytocin-ir terminals form synapses with dendrites or soma of the sympathetic preganglionic neurons. The terminals contained numerous small clear round vesicles and a few large, cored vesicles. These results clearly show that a large proportion of SPNs are innervated by oxytocin-containing fibers. The origin of these fibers is discussed, and it is concluded that they are probably descending fibers from the paraventricular nucleus of the hypothalamus.     

Descending input from the hypothalamic paraventricular nucleus to sympathetic preganglionic neurons in the rat

Summary The descending projection of the hypothalamic paraventricular nucleus (PVN) to the sympathetic preganglionic neurons (SPNs) in the upper thoracic cord of the rat was studied. PVN-fibers were labeled by anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L), while SPNs were retrogradely labeled with cholera toxin subunit B (CTb) which was injected into the superior cervical ganglion. SPNs labeled with CTb were mainly observed in the nucleus intermediolateralis (IML) pars principalis and pars funicularis, and a small number of them were in the nucleus intercalatus (IC) and central autonomic nucleus (CA). SPNs found in the IML had dendrites that projected in various directions. Five types of dendritic projections were noted: medial, rostral, caudal, lateral (including dorsolateral) and ventral. Longitudinal dendritic bundles interconnected each cell cluster in the IML. Medial dendrites of the IML, together with dendrites of the IC and CA, formed transverse dendritic bundles extending from the IML to the central canal. The transverse dendritic bundles disentangled near the midline and formed a loose dendritic plexus in the region just dorsal to the central canal. PVN-fibers labeled with PHA-L were observed primarily in lamina I and intermediate gray (lamina VII). Although varicose PVN-fibers and SPNs coexisted in the IML, the tight packing of the dendritic bundles prevented any clear demonstration of direct contacts between them. On the other hand, PVN-fibers were occasionally found to appose and wind around the primary or secondary dendrites of some SPNs of the CA and IC. These dendrites were studded with varicosities of PVN-fibers for a short length, and terminal boutons of PVN-fibers were also seen to make contact directly with the dendrites. The results of this study substantiated a direct connection between the PVN and SPNs, using a combination of immunohistochemical techniques for PHA-L and CTb. The possible involvement of a direct pathway from the PVN to SPNs in cardiovascular regulation is discussed.Abbreviations AF anterior funiculus - CA central autonomic nucleus - CC central canal - CTb cholera toxin subunit B - HRP horseradish peroxidase - IC nucleus intercalatus - IMf nucleus intermediolateralis pars funicularis - IML nucleus intermediolateralis - IMp nucleus intermediolateralis pars principalis - LDB longitudinal dendritic bundle - LF lateral funiculus - PF posterior funiculus - PHA-L Phaseolus vulgaris leucoagglutinin - PVN hypothalamic paraventricular nucleus - SPNs sympathetic preganglionic neurons - TDB transverse dendritic bundle     

Thiopental inhibits glycine receptor function in acutely dissociated rat spinal dorsal horn neurons

Whole-cell patch-clamp was used to assess the modulatory effect of thiopental (Thio) on glycine (Gly) receptor in mechanically dissociated rat spinal dorsal horn neurons. It was found that Thio inhibited the amplitude, accelerated the desensitization and prolonged the deactivation of Gly-induced currents (I_Gly) in a concentration-dependent manner. In addition, a rebound current occurred after washout of the co-application of Gly and Thio in most neurons tested. Moreover, the inhibitory effect of Thio was not the result of cross-inhibition between Gly and GABA_A receptors. Furthermore, taurine-induced currents, a low-affinity agonist for Gly receptors, were also markedly inhibited by Thio in a similar way to I_Gly. These results indicate that Thio suppresses Gly receptor function and suggest that Thio anesthetic actions might not be mediated by Gly receptors. We speculate that the weak muscle relaxation and the limited analgesic effects observed during Thio anesthesia may attribute to its inhibitory effects on Gly receptors.     

Glutamate- and GABA-immunoreactive synapses on sympathetic preganglionic neurons caudal to a spinal cord transection in rats

Spinal cord injury destroys bulbospinal amino acid-containing pathways to sympathetic preganglionic neurons and severely disrupts blood pressure control, resulting in resting or postural hypotension and episodic hypertension. Almost all immunoreactivity for the excitatory amino acid l-glutamate has been reported to disappear from autonomic areas of the cord caudal to a transection, apparently depriving autonomic neurons of their major excitatory input. However, the magnitude of the neurogenic episodic hypertension after cord injury suggests that excitatory inputs to sympathetic preganglionic neurons must still be present. Moreover, the hypotension associated with high spinal injuries may reflect a enhanced role for inhibitory transmitters, such as GABA. This apparent contradiction regarding the presence of glutamate and lack of information about GABA prompted the present investigation. In rats seven days after spinal cord transection, we examined identified sympathetic preganglionic neurons caudal to the injury for the presence of synapses or direct contacts from varicosities that were immunoreactive for the amino acids, l-glutamate and GABA. Adrenal sympathetic preganglionic neurons were retrogradely labelled with cholera toxin B subunit and amino acid immunoreactivity was revealed with post-embedding immunogold labelling. In single ultrathin sections, 46% (98/212) of the synapses or direct contacts on adrenal sympathetic preganglionic neurons were immunoreactive for glutamate and 39% (83/214) were immunoreactive for GABA. Analysis of inputs with the physical disector yielded similar results for the two amino acids. The proportions of glutamatergic or GABAergic synapses on cell bodies and dendrites were similar. When alternate ultrathin sections were stained to reveal glutamate or GABA immunoreactivity, either one or the other amino acid occurred in 78.4% (116/148) of inputs; 4.1% (6/148) of inputs contained both amino acids and 17.5% (26/148) of inputs contained neither.These results demonstrate that nerve fibres immunoreactive for the neurotransmitter amino acids, glutamate and GABA, provide most of the input to sympathetic preganglionic neurons caudal to a spinal cord transection. Synapses containing glutamate and GABA could provide the anatomical substrate for the exaggerated sympathetic reflexes and the low sympathetic tone that result from spinal cord injury.     

支配肺血管的脊髓交感神经中枢定位

在大鼠毁髓模型上,对由脊髓C_7～T_(10)节段发出的交感节前纤维逐节进行电刺激时,发现肺循环阻力(PVR)均有不同程度的升高,但在刺激脊髓C_7～T_4节段时PVR升高最为显著(对照值的28%),明显高于其余各节段电刺激后PVR增加的水平。刺激的脊髓节段愈高,△PVR/△SVR比值也愈大。体循环阻力(SVR)的升高则以低位脊髓节段的电刺激时更明显。提示在大鼠脊髓C_7～T_4节段存在支配肺血管运动的交感神经中枢。     

Confocal imaging of autonomic preganglionic neurons in the spinal cord of the caecilian Typhlonectes natans (Amphibia: Gymnophiona)

Little is known about the spinal sympathetic organization in the caecilian amphibians. We examined for the first time the location of sympathetic preganglionic neurons (SPNs) in the spinal cord using a panel of specific markers expressed in SPNs. The SPNs of anuran amphibians form two cell columns segregated mainly in the lateral and medial marginal areas of the central gray matter. In the caecilian Typhlonectes natans immunoreactivity for galanin and ChAT is found in most laterally arranged neurons lying in spinal segments 2–7. They are encircled by TH- and nNOS-immunoreactive nerve fibers. These neurons might project specifically to a population of adrenergic sympathetic postganglionic neurons in paravertebral ganglia and/or non-adrenergic sympathetic postganglionic neurons in the celiac ganglia. However the segmental restriction and target specificity of the neurons of the species studied are not known. As mucous and granular glands in the dermis may represent one of the peripheral targets of the adrenergic ganglion cells and reflect the prominent preganglionic cell columns, an immunohistochemical study was done also on these glands. Retrograde-tracing studies are, however, needed to study the segmental localization of the preganglionic neurons and their projections to the postganglionic neurons in sympathetic ganglia.     

Thoracolumbar sympathetic preganglionic neurons in the dorsal commissural nucleus of the male rat: an immunohistochemical study using retrograde labeling of cholera toxin subunit B

The cell morphology of sympathetic preganglionic neurons (SPNs) in the dorsal commissural nucleus was studied by the retrograde labeling technique using cholera toxin subunit B (CTb) as a tracer. A small amount of an aqueous solution of CTb was injected unilaterally into the major pelvic ganglion of the male rat. Labeled SPNs were detected immunohistochemically using anti-CTb antiserum. Most of the labeled SPNs were observed in L₁ to L₃, and a very small number in T₁₃. They were observed bilaterally in the sympathetic nuclei, such as the intermediolateral cell column, intercalated nucleus and the dorsal commissural nucleus. A loose network of longitudinally or transversely oriented SPN dendrites was located within the dorsal commissural nucleus itself. The lateral margin of the dorsal commissural nucleus was roughly demarcated by longitudinally oriented dendrites. Together with the dendrites of the SPNs of the intercalated and intermediolateral cell column, laterally oriented dendrites of the dorsal commissural nucleus converged and formed the transverse dendritic bundles in the intermediate zone that connect the dorsal commissural nucleus and the intermediolateral cell column. The transverse dendritic bundles were arranged periodically. The axons of the SPNs in the dorsal commissural nucleus traveled laterally into the transverse dendritic bundles, then turned ventrally near the intermediolateral cell column, and finally entered the ventral funiculus. After rhizotomy of the ventral roots of the upper lumbar cord, labeled SPNs were found only on the side contralateral to the rhizotomy. The dorsal commissural nucleus appears as a compact single cell column, but our results clearly show that this nucleus actually consists of two adjacent parallel columns of cells.     

大鼠脊髓源神经干细胞与运动神经元的差异蛋白质组学

目的 探讨大鼠脊髓源神经干细胞与运动神经元的差异蛋白质组学,寻找出重要的差异蛋白质.方法 采用双向电泳分离两种细胞的蛋白质,用DeCyder软件分析蛋白表达差异,并采用质谱(HPLC-ESI-MS/MS)进行鉴定.结果 脊髓源神经干细胞与运动神经元蛋白质凝胶分析获得1 300余个清晰的蛋白质斑点,在比国产分析的87个差异点中,初步鉴定出44个差异表达蛋白,其中24个在神经干细胞高表达,20个在运动神经元高表达.结论 脊髓源神经干细胞与运动神经元有各自特定的蛋白质表达,某些差异蛋白可能在神经干细胞向运动神经元分化中发挥关键作用.     

Electrophysiological characteristics of vasomotor preganglionic neurons and related neurons in the thoracic spinal cord of the rat: an intracellular study in vivo

Sympathetic preganglionic neurons (SPN) represent the final central neurons in the sympathetic pathways which regulate vasomotor tone; they therefore play a pivotal role in the re-distribution of cardiac output to different vascular beds in response to environmental challenges. While the consensus view is that activity in these neurons is due mainly to supraspinal inputs, the possibility that some activity may be generated intrinsically and modified by synaptic inputs cannot be excluded. Therefore, in order to distinguish between these two possibilities, the electrophysiological properties of cardiovascular-like SPN in the upper thoracic spinal cord of the anesthetized rat were examined and their response to activation of vasodepressor inputs was investigated. Intracellular recordings were made from 22 antidromically identified SPN of which 17 displayed irregular, but maintained, spontaneous activity; no evidence of bursting behavior or pacemaker-like activity was observed. Stimulation of the aortic depressor nerve or a vasodepressor site within the nucleus tractus solitarius (NTS) resulted in a membrane hyperpolarization, decrease in cell input resistance and long-lasting cessation of neuronal firing in SPN including a sub-population which had cardiac-modulated patterns of activity patterns. Recordings were also undertaken from 80 non-antidromically-activated neurons located in the vicinity of SPN; 23% of which fired in phase with the cardiac cycle, with this peak of activity occurring before similar increases in cardiac-modulated SPN. Stimulation of vasodepressor regions of the NTS evoked a membrane hyperpolarization and decrease in cell input resistance in cardiac-modulated but not non-modulated interneurons. These studies show that activity patterns in SPN in vivo are determined principally by synaptic inputs. They also demonstrate that spinal interneurons which exhibit cardiac-modulated patterns of activity are postsynaptically inhibited following activation of baroreceptor pathways. However, the question as to whether these inhibitory pathways and/or disfacilitation of tonic excitatory drive underlies the baroreceptor-mediated inhibition of SPN remains to be determined.     

The release of amino acids synthesised from various compartmented precursors in rat spinal cord slices

Summary [¹⁴C]Glucose and [¹⁴C]acetate have been used to label amino acid pools believed to be localised in neurones and glia, respectively, in small slices of rat spinal cord. The effects of depolarising agents on the efflux of amino acids from these pools were compared and contrasted with their effect on the efflux of exogenous [³H]glutamate. Elevated (50 mM) potassium in the superfusing medium increased the release of glutamate, aspartate and GABA synthesised from either glucose or acetate and that of exogenous glutamate. These increases were not, however, abolished by tetrodotoxin (2 M). Protoveratrine A (10^-4 M), on the other hand, elevated the efflux of glutamate, GABA and possibly aspartate when these amino acids were synthesised from glucose, but not when acetate was the labelled precursor. Furthermore, this effect was abolished by 2 M tetrodotoxin. It is concluded that these techniques point to the existence in slices of spinal cord of neuronal pools of glutamate, GABA and possibly aspartate that may be released as a consequence of neuronal activity, and that these pools probably represent transmitter stores of these amino acids.     

A transient outward rectification in the cat sympathetic preganglionic neuron

Intracellular recordings were made from sympathetic pregangionic neurons of the intermediolateral nucleus, in the slice of the T3 segment of the cat spinal cord. Depolarization to –60 mV from membrane potentials more negative than –75 to –80 mV caused a transient outward rectification which decayed in 0.5–2.0s. The rectification was sensitive to changes in K concentation, was abolished by 4AP (2 mM), and was unaffected by low Ca (0.25 mM), Co (2 mM), Ba (1 mM), TEA (20 mM) or intracellular Cs. These properties suggest that the rectification is due to a transient K-current similar to the A-current described in other neurons.     

The organization of spinal motor neurons in a monotreme is consistent with a six‐region schema of the mammalian spinal cord

The motor neurons in the spinal cord of an echidna (Tachyglossus aculeatus) have been mapped in Nissl‐stained sections from spinal cord segments defined by spinal nerve anatomy. A medial motor column of motor neurons is found at all spinal cord levels, and a hypaxial column is found at most levels. The organization of the motor neuron clusters in the lateral motor column of the brachial (C5 to T3) and crural (L2 to S3) limb enlargements is very similar to the pattern previously revealed by retrograde tracing in placental mammals, and the motor neuron clusters have been tentatively identified according to the muscle groups they are likely to supply. The region separating the two limb enlargements (T4 to L1) contains preganglionic motor neurons that appear to represent the spinal sympathetic outflow. Immediately caudal to the crural limb enlargement is a short column of preganglionic motor neurons (S3 to S4), which it is believed represents the pelvic parasympathetic outflow. The rostral and caudal ends of the spinal cord contain neither a lateral motor column nor a preganglionic column. Branchial motor neurons (which are believed to supply the sternomastoid and trapezius muscles) are present at the lateral margin of the ventral horn in rostral cervical segments (C2–C4). These same segments contain the phrenic nucleus, which belongs to the hypaxial column. The presence or absence of the main spinal motor neuron columns in the different regions echidna spinal cord (and also in that of other amniote vertebrates) provides a basis for dividing the spinal cord into six main regions – prebrachial, brachial, postbrachial, crural, postcrural and caudal. The considerable biological and functional significance of this subdivision pattern is supported by recent studies on spinal cord hox gene expression in chicks and mice. On the other hand, the familiar ‘segments’ of the spinal cord are defined only by the anatomy of adjacent vertebrae, and are not demarcated by intrinsic gene expression. The recognition of segments defined by vertebrae (somites) is obviously of great value in defining topography, but the emphasis on such segments obscures the underlying evolutionary reality of a spinal cord comprised of six genetically defined regions. The six‐region system can be usefully applied to the spinal cord of any amniote (and probably most anurans), independent of the number of vertebral segments in each part of the spinal column.     

大鼠脊髓神经元对福尔马林痛刺激的反应及氯胺酮的调节

目的：研究大鼠脊髓对福尔马林痛刺激的反应及氯胺酮的影响。方法：采用福尔马林致痛模型、c-fos基因免疫组化法和NADPH-d组化技术。SD大鼠30只，分为福尔马林致痛组、痛刺激前和后腹腔注射氯胺酮组及相应对照组，取脊髓切片。结果：(1)痛刺激后，刺激侧脊髓背角出现大量Fos免疫样阳性(FLI)神经元，其中部分为FLI／NOS双标记神经元；(2)痛刺激之前或之后给予氯胺酮，背角各层FLI神经元和FLI／NOS双标记神经元的数量均显著减少。结论：同侧相应脊髓节段的某些神经元参与了化学性致痛信息的传导和调控，氯胺酮通过抑制这些神经元的活动而产生抗伤害作用。此作用与抑制脊髓内NOS阳性神经元的活性有关。     

The distribution of spinal projection neurons in the hypothalamus of the rat,studied with the HRP method

Summary The distribution and number of hypothalamospinal tract (HST) neurons were studied following injections of horseradish peroxidase (HRP) at various levels of the rat spinal cord. The hypothalamus was divided into four areas and one nucleus, that is, the dorsal (DHA), posterior (PHA), medial (MHA) and lateral (LHA) hypothalamic areas and the paraventricular nucleus (PVN).The total numbers of HST neurons labeled with HRP varied according to the injection levels: 6,160 (C₂ injections), 3,808 (T₈), 1,961 (L₁), 919 (L₇) and 13 (S₄). With C₂ injections LHA contained 3,464 neurons, which accounted for 56% of the full number of HST neurons; similarly, PVN, 1,114 (18%); MHA, 865 (14%); DHA and PHA, 817 (12%). With L₇ injections, LHA contained 444 labeled neurons, which accounted for 48% of the total; PVN, 327 (36%); MHA, 71 (8%); DHA with PHA, 77 (8%). As for the rostrocaudal distribution of labeled neurons, there was only a slight difference between the C₂ and L₆ injections in LHA, but no difference was noticed in PVN, DHA nor PHA.The present findings suggest that 70% of HST neurons may project to the cervical and thoracic cords. Although the number of labeled HST neurons decreased as the injection sites were placed caudally, no clearcut topographical arrangement was recognized in terms of the spinal projection levels.Abbreviations AHN anterior hypothalamic nucleus - ARN hypothalamic arcuate nucleus - CI internal capsule - CP cerebral peduncle - DHA dorsal hypothalamic area - DK nucleus of Darkschewitsch - DMN hypothalamic dorsomedial nucleus - EW Edinger-Westphal nucleus - F fornix - FF field of Forel - FR fasciculus retroflexus - HRP horseradish peroxidase - HST hypothalamospinal tract - INS interstitial nucleus of Cajal - LHA lateral hypothalamic area - LHAd dorsal part of the lateral hypothalamic area - LHAv ventral part of the lateral hypothalamic area - LM medial lemniscus - ME median eminence - MHA medial hypothalamic area - MHAd dorsal part of the medial hypothalamic area - MHAv ventral part of the medial hypothalamic area - MMN medial mammillary nucleus - MT mammillothalamic tract - OT optic tract - PHA posterior hypothalamic area - PVN paraventricular nucleus - RCA retrochiasmatic area - RN red nucleus - SMN supramammillary nucleus - SO supraoptic nucleus - VMN hypothalamic ventromedial nucleus - VTA ventral tegmental area - ZI zona incerta     

B-vitamins enhance afferent inhibitory controls of nociceptive neurons in the rat spinal cord

Summary Afferent inhibition of spinal dorsal horn neuronal responses to noxious skin heating was induced by transcutaneous electrical nerve stimulation in pentobarbital-anesthetized rats. Pretreatment with B vitamins significantly enhanced this afferent inhibition, possibly due to an increase in the synthesis rate of inhibitory neurotransmitters in central neurones.     

Nesfatin-1 immunoreactivity in rat brain and spinal cord autonomic nuclei

Nesfatin-1 is one of the peptide products of posttranslational processing of the nucleobindin-2 (NUCB2) gene, suggested to have physiological relevance to suppress food intake and body weight gain in rats. Nesfatin-1-immunoreactive cells have been found in distinct nuclei in the rat brain related to circuitries regulating food intake. Here, we report novel yet undescribed localization of NUCB2/nesfatin-1 at the mRNA and protein level in the rat central nervous system. Immunohistochemical staining revealed the localization of NUCB2/nesfatin-1 in the piriform and insular cortex, endopiriform nucleus, nucleus accumbens, lateral septum, bed nucleus of stria terminalis, central amygdaloid nucleus, medial preoptic area, dorsal raphe nucleus, ambiguus nucleus, ventrolateral medulla and gigantocellular reticular nucleus, as well as Purkinje-cells of the cerebellum. In the spinal cord, nesfatin-1 immunoreactivity (IR) was found in both sympathetic and parasympathetic preganglionic neuronal groups and in the dorsal area X from lower thoracic to sacral segments. The immunohistochemical results were confirmed by RT-PCR in the central amygdaloid nucleus, nucleus accumbens, cerebellum and lumbar spinal cord microdissected by punch technique. The features and distributions of nesfatin-1 IR and mRNA expression in the brain and spinal cord suggest that NUCB2/nesfatin-1 could play a wider role in autonomic regulation of visceral-endocrine functions besides food intake.     

Localization of N-type Ca2+ channels in the rat spinal cord following chronic constrictive nerve injury

Previous studies have shown that spinal L-type, N-type, and P-type Ca²⁺-channel blockers are effective in modulating pain behavior caused nerve injury. In the present work, using the loose ligation of the sciatic nerve model, we characterized the time course of the appearance of tactile and cold allodynia and the corresponding spinal expression of the N-type Ca²⁺ channel α_1B-subunit after nerve ligation. Within 1 week after ligation, the majority of rats developed a unilateral sensitivity to mechanical stimulation (von Frey filaments), as well as sensitivity to cold, which persisted for 30 days. Immunocytochemical analysis of the spinal cord in sham-operated animals for the α_1B-subunit showed a smooth, moderate staining pattern in the superficial laminae I–II, as well as in ventral α-motoneurons. In nerve-ligated animals, an intense, dot-like immunoreactivity in the ipsilateral dorsal horn was observed from 5–20 days after nerve ligation. The most prominent α_1B-subunit upregulation was found in the outer as well as the inner part of lamina II (II_o, II_i), extending from the medial toward the lateral region of the L4 and L5 spinal segments. The behavioral changes which developed after chronic constriction injury directly correlated with the α_1B-subunit upregulation in the corresponding spinal cord segments. These data suggest that upregulation of the spinal α_1B-subunit may play an important role in the initiation and maintenance of pain state after peripheral nerve injury. Electronic Publication