Lamina specific postnatal development of PKCγ interneurons within the rat medullary dorsal horn

Protein kinase C gamma (PKCγ) interneurons, located in the superficial spinal (SDH) and medullary dorsal horns (MDH), have been shown to play a critical role in cutaneous mechanical hypersensitivity. However, a thorough characterization of their development in the MDH is lacking. Here, it is shown that the number of PKCγ‐ir interneurons changes from postnatal day 3 (P3) to P60 (adult) and such developmental changes differ according to laminae. PKCγ‐ir interneurons are already present at P3‐5 in laminae I, IIo, and III. In lamina III, they then decrease from P11–P15 to P60. Interestingly, PKCγ‐ir interneurons appear only at P6 in lamina IIi, and they conversely increase to reach adult levels at P11–15. Analysis of neurogenesis using bromodeoxyuridine (BrdU) does not detect any PKCγ‐BrdU double‐labeling in lamina IIi. Quantification of the neuronal marker, NeuN, reveals a sharp neuronal decline (∼50%) within all superficial MDH laminae during early development (P3–15), suggesting that developmental changes in PKCγ‐ir interneurons are independent from those of other neurons. Finally, neonatal capsaicin treatment, which produces a permanent loss of most unmyelinated afferent fibers, has no effect on the development of PKCγ‐ir interneurons. Together, the results show that: (i) the expression of PKCγ‐ir interneurons in MDH is developmentally regulated with a critical period at P11‐P15, (ii) PKCγ‐ir interneurons are developmentally heterogeneous, (iii) lamina IIi PKCγ‐ir interneurons appear less vulnerable to cell death, and (iv) postnatal maturation of PKCγ‐ir interneurons is due to neither neurogenesis, nor neuronal migration, and is independent of C‐fiber development. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 102–119, 2017     

The calcium binding proteins calbindin,parvalbumin, and calretinin have specific patterns of expression in the gray matter of cat spinal cord

Calcium binding proteins (CBPs) regulate intracellular levels of calcium (Ca²⁺) ions. CBPs are particularly interesting from a morphological standpoint, because they are differentially expressed in certain sub-populations of cells in the nervous system of various species of vertebrate animals. However, knowledge on the cellular regulation governing such cell-specific CBP expression is still incomplete. In this work on the L7 segment of the cat spinal cord, we analyzed the localization and morphology of neurons expressing the CBPs calbindin-28 KD (CB), parvalbumin (PV), and calretinin (CR), and co-expressing CB and PV, CB and CR, and PV and CR. Single CBP-positive (⁺) neurons showed specific distributions: (1) CB was present in small neurons localized in laminae I, II, III and X, in small to medium size neurons in laminae III–VI, and in medium to large neurons in laminae VI–VIII; (2) PV was present in small size neurons in laminae III and IV and in medial portions of laminae V and VI, medium neurons and in lamina X at the border with lamina VII, in medium to large neurons in laminae VII and VIII; (3) CR labeling was detected in small size neurons in laminae I, II, III and VIII, in medium to large size neurons in laminae I and III–VII, and in small to medium size neurons in lamina X. Double labeled neurons were a small minority of the CBP⁺ cells. Co-expression of CB and PV was seen in 1 to 2% of the CBP⁺ cells, and they were detected in the ventral and intermediate portions of lamina VII and in lamina X. Co-localization of CB and CR was present in 0.3% of the cells and these cells were localized in lamina II. Double labeling for PV and CR occurred in 6% of the cells, and the cells were localized in ventral part of lamina VII and in lamina VIII. Overall, these results revealed distinct and reproducible patterns of localization of the neurons expressing single CBPs and co-expressing two of them. Distinct differences of CBP expression between cat and other species are discussed. Possible relations between the cat L7 neurons expressing different CBPs with the neurons previously analyzed in cat and other animals are suggested.     

去甲肾上腺素在脊髓背角的镇痛机制

疹髓背角浅层是传递和调制外周伤害性信息的关键部位。起源于脑干的去甲肾上腺素（NA）能纤维终止脊髓背角,它们释放的NA具有抑制初级传入末梢释放谷氨酸和P物质、增加Ⅱ层（胶状质）抑制性神经活性物质释放的作用。此外,形态学研究提示NA可能直接抑制Ⅰ/Ⅲ层向丘脑传递伤害性信息的投射神经元。NA可能通过以上途径,实现对外周伤害性信息传递的调制而发挥镇痛作用。     

Ultrastructural study of neurotensin immunoreactivity in the superficial laminae of the dorsal horn of the rat

Neurotensin immunoreactivity was identified in cell bodies, dendrites, spines, axons, terminals and varicosities in superficial laminae of rat spinal cord with the electron microscope. Unlabeled terminals synapsed with neurotensin-immunoreactive cell bodies, dendrites and spines. Presynaptic terminals contained round or pleomorphic vesicles and generally made symmetrical contacts with medium-sized neurotensin-containing dendrites in outer lamina II, and asymmetrical or symmetrical contacts with large and small dendrites and spines in inner lamina II. Neurotensin immunoreactive axons were unmyelinated, and their terminals were presynaptic to unlabeled dendrites and spines in laminae I and II. Terminals contained small, round, clear vesciles (31 nm) and occasional large granular vesicles (78 nm). Contacts in outer lamina II were evenly distributed among dendrites of various sizes and spines, whereas the majority of labeled terminals in inner lamina II made contacts onto small dendrites and spines. These findings indicate that neurotensin effects in rat spinal cord are mediated by axodendritic synapses, and that neurotensin cells at the inner and outer borders of lamina II contact dendrites of efferent neurons or other interneurons in the dorsal horn.     

Ulex europaeus agglutinin-I binding to dental primary afferent projections in the spinal trigeminal complex combined with double immunolabeling of substance P and GABA elements using peroxidase and colloidal gold

Ulex europaeus agglutinin I (UEA-I) is a plant lectin with an affinity for L-fucosyl residues in the chains of lactoseries oligosaccharides associated with medium- and smaller-diameter dorsal root ganglion neurons and their axonal processes. These enter Lissauer's tract and terminate within the superficial laminae of the spinal cord overlapping projections known to have a nociceptive function. This implies that the surface coatings of neuronal membranes may have a relationship with functional modalities. The present investigation further examined this concept by studying a neuronal projection with a nociceptive function to determine whether fucosyl-lactoseries residues were incorporated in its primary afferent terminals. Transganglionic transport of horseradish peroxidase (HRP) following injection into tooth pulp chambers was employed to demonstrate dental pulp terminals in the trigeminal spinal complex, while peroxidase and fluorescent tags were used concomitantly to stain for UEA-I. Double immunolabeling for substance P (SP) and gamma-aminobutyric acid (GABA) using peroxidase and colloidal gold allowed a comparison of the distribution of a known excitatory nociceptive transmitter with that of UEA-I binding in specific subnuclei. Synaptic interrelationships between UEA-I positive dental pulp primary afferent inputs and specific inhibitory terminals were also examined. SP immunoreactivity occurred in laminae I and outer lamina II (IIo) of subnucleus caudalis (Vc) and in the ventrolateral and lateral marginal region of the caudal half of subnucleus interpolaris (Vi), including the periobex area in which Vi is slightly overlapped on its lateral aspect by cellular elements of Vc. The adjacent interstitial nucleus (IN) also showed an intense immunoreactivity for this peptide antibody. UEA-I binding displayed a similar distribution pattern in both Vc and Vi, but extended into lamina IIi and the superficial part of Lamina III in Vc. Dental pulp terminals were found to have a comparable distribution; however, many extended into the dorsal portion of the caudal half of Vi and the ventromedial quadrant of rostral Vi. Electron-microscopic analysis showed that transganglionically labeled dental pulp terminals contained ovoid, complex membrane-bound vacuoles laden with transported HRP. The preterminal axon and synaptic membranes of those dental pulp terminals located in zones of Vc and Vi displaying an affinity for UEA-I were usually characterized by a patchy, electron-dense coating of the peroxidase tag. SP was demonstrated ultrastructurally with Protein-A colloidal gold (3-nm particles), whereas GABA immunoreactivity was revealed by the avidin-biotin-peroxidase method.(ABSTRACT TRUNCATED AT 400 WORDS)     

Ulex europaeus Agglutinin-I Binding to Dental Primary Afferent Projections in the Spinal Trigeminal Complex Combined with Double Immunolabeling of Substance P and GABA Elements Using Peroxidase and Colloidal Gold

Ulex europaeus agglutinin I (UEA-I) is a plant lectin with an affinity for L-fucosyl residues in the chains of lactoseries oligosaccharides associated with medium and smaller-diameter dorsal root ganglion neurons and their axonal processes. These enter Lissauer's tract and terminate within the superficial laminae of the spinal cord overlapping projections known to have a nociceptive function. This implies that the surface coatings of neuronal membranes may have a relationship with functional modalities. The present investigation further examined this concept by studying a neuronal projection with a nociceptive function to determine whether fucosyl-lactoseries residues were incorporated in its primary afferent terminals. Transganglionic transport of horseradish peroxidase (HRP) following injection into tooth pulp chambers was employed to demonstrate dental pulp terminals in the trigeminal spinal complex, while peroxidase and fluorescent tags were used concomitantly to stain for UEA-I. Double immunolabeling for substance P (SP) and γ-aminobutyric acid (GABA) using peroxidase and colloidal gold allowed a comparison of the distribution of a known excitatory nociceptive transmitter with that of UEA-I binding in specific subnuclei. Synaptic interrelationships between UEA-I positive dental pulp primary afferent inputs and specific inhibitory terminals were also examined.

SP immunoreactivity occurred in laminae I and outer lamina II (II_o) of subnucleus caudalis (Vc) and in the ventrolateral and lateral marginal region of the caudal half of subnucleus interpolaris (Vi), including the periobex area in which Vi is slightly overlapped on its lateral aspect by cellular elements of Vc. The adjacent interstitial nucleus (IN) also showed an intense immunoreactivity for this peptide antibody. UEA-I binding displayed a similar distribution pattern in both Vc and Vi, but extended into lamina II; and the superficial part of Lamina III in Vc. Dental pulp terminals were found to have a comparable distribution; however, many extended into the dorsal portion of the caudal half of Vi and the ventromedial quadrant of rostral Vi.

Electron-microscopic analysis showed that transganglionically labeled dental pulp terminals contained ovoid, complex membrane-bound vacuoles laden with transported HRP. The preterminal axon and synaptic membranes of those dental pulp terminals located in zones of Vc and Vi displaying an affinity for UEA-I were usually characterized by a patchy, electron-dense coating of the peroxidase tag. SP was demonstrated ultrastructurally with Protein-A colloidal gold (3-nm particles), whereas GABA immunoreactivity was revealed by the avidin—biotin—peroxidase method. This combined approach labeled a variety of simple axodendritic to large complex scalloped dental terminals which contained SP and were shown to have a UEA-I affinity. In addition, many of the larger terminals formed contacts with GABA-ergic dendrites and received inputs from GABA-ergic synapses. These complexes were most concentrated in lamina II_o of Vc and the ventrolateral zone of Vi. Many terminals in laminae II_i; and III with a UEA-I-positive surface coating failed to bind with the antiserum for SP, indicating that other transmitters may colocalize with UEA-I and suggesting that absolute correlations between specific oligosaccharide plasmalemmal coatings and functional modalities should be approached with caution. Further studies employing antisera to different transmitters are currently underway to better define the relationship between transmitter localization and anatomical substrates within this circuitry. These studies should eventually provide additional clues about relationships between functional properties and oligosaccharide coatings of primary afferent projections.     

Experimental morphological study of primary afferent terminals at the base of the dorsal horn of the cat spinal cord

The distribution and ultrastructure of primary afferent terminals in the gray matter of the cervical and lumbar regions of the cat spinal cord were studied by the experimental degeneration method of Fink and Heimer. Most preterminals of primary afferents were shown to be concentrated in the region of the intermediate nucleus of Cajal (central part of Rexed's laminae VI–VII), in the substantial gelatinosa (laminae II–III), and in the nucleus proprius of the dorsal horn (central and medial parts of lamina IV). Fewer are found in the region of the motor nuclei. The number of degenerating axon terminals in the lateral parts of laminae IV and V differed: 31.5 and 0.4% respectively of all axon terminals. Many terminals of primary afferents in lamina IV contribute to the formation of glomerular structures in which they exist as terminals of S-type forming axo-axonal connections with other terminals. These results are in agreement with electrophysiological data to show that interneurons in different parts of the base of the dorsal horn differ significantly in the relative numbers of synaptic inputs formed by peripheral afferents and descending systems.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 5, No. 4, pp. 406–414, July–August, 1973.     

Neural organization of the lamina neuropil of the larva of the tiger beetle (Cicindela chinensis)

Six neural elements, viz., retinular axons, a giant monopolar axon, straight descending processes (type I), lamina monopolar axons (type II), processes containing clusters of dense-core vesicles (type III), and processes coursing in various directions with varicosities (type IV), have been identified at the ultrastructural level in the lamina neuropil of the larval tiger beetle Cicindela chinensis. Retinular axons make presynaptic contact with all other types of processes. Type I and II processes possess many pre-and postsynaptic loci. Type II processes presumably constitute retinotopic afferent pathways. It remains uncertain whether type I processes are lamina monopolar axons or long retinular axons extending to the medullar neuropil. Type III processes may be efferent neurons or branches of afferent neurons contributing to local circuits. A giant monopolar axon extends many branches throughout the lamina neuropil; these branches are postsynaptic to retinular axons, and may be nonretinotopic and afferent. Type IV processes course obliquely in the neuropil, being postsynaptic to retinular axons, and presynaptic to type I processes.     

GABA immunoreactivity in the human cerebellar cortex: a light and electron microscopical study

The distribution of gamma-aminobutyric acid (GABA) in surgical samples of human cerebellar cortex was studied by light and electron microscope immunocytochemistry using a polyclonal antibody generated in rabbit against GABA coupled to bovine serum albumin with glutaraldehyde. Observations by light microscopy revealed immunostained neuronal bodies and processes as well as axon terminals in all layers of the cerebellar cortex. Perikarya of stellate, basket and Golgi neurons showed evident GABA immunoreactivity. In contrast, perikarya of Purkinje neurons appeared to be negative or weakly positive. Immunoreactive tracts of longitudinally- or obliquely-sectioned neuronal processes and punctate elements, corresponding to axon terminals or cross-sectioned neuronal processes, showed a layer-specific pattern of distribution and were seen on the surface of neuronal bodies, in the neuropil and at microvessel walls. Electron microscope observations mainly focussed on the analysis of GABA-labelled axon terminals and of their relationships with neurons and microvessels. GABA-labelled terminals contained gold particles associated with pleomorphic vesicles and mitochondria and established symmetric synapses with neuronal bodies and dendrites in all cortex layers. GABA-labelled terminals associated with capillaries were seen to contact the perivascular glial processes, basal lamina and endothelial cells and to establish synapses with subendothelial unlabelled axons.     

Synaptic patterns in the dorsal lateral geniculate nucleus of the monkey

Summary Synaptic junctions are found in all parts of the nucleus, being almost as densely distributed between cell laminae as within these laminae.In addition to the six classical cell laminae, two thin intercalated laminae have been found which lie on each side of lamina 1. These laminae contain small neurons embedded in a zone of small neural processes and many axo-axonal synapses occur there.Three types of axon form synapses in all cell laminae and have been called RLP, RSD and F axons. RLP axons have large terminals which contain loosely packed round synaptic vesicles, RSD axons have small terminals which contain closely packed round vesicles and F axons have terminals intermediate in size containing many flattened vesicles.RLP axons are identified as retinogeniculate fibers. Their terminals are confined to the cell laminae, where they form filamentous contacts upon large dendrites and asymmetrical regular synaptic contacts (with a thin postsynaptic opacity) upon large dendrites and F axons. RSD axons terminate within the cellular laminae and also between them. They form asymmetrical regular synaptic contacts on small dendrites and on F axons. F axons, which also occur throughout the nucleus, form symmetrical regular contacts upon all portions of the geniculate neurons and with other F axons. At axo-axonal junctions the F axon is always postsynaptic.Supported by Grant R 01 NB 06662 from the USPHS and by funds of the Neurological Sciences Group of the Medical Research Council of Canada. Most of the observations were made while R. W. Guillery was a visiting professor in the Department of Physiology at the University of Montreal. We thank the Department of Physiology for their support and Mr. K. Watkins, Mrs. E. Langer and Mrs. B. Yelk for their skillful technical assistance.     

Glutamatergic components of the retrosplenial granular cortex in the rat

The ultrastructural characteristics, distribution and synaptic relationships of identified, glutamate-enriched thalamocortical axon terminals and cell bodies in the retrosplenial granular cortex of adult rats is described and compared with GABA-containing terminals and cell bodies, using postembedding immunogold immunohistochemistry and transmission electron microscopy in animals with injections of cholera toxin- horseradish peroxidase (CT-HRP) into the anterior thalamic nuclei. Anterogradely labelled terminals, identified by semi-crystalline deposits of HRP reaction product, were approximately 1 μm in diameter, contained round, clear synaptic vesicles, and established asymmetric (Gray type I) synaptic contacts with dendritic spines and small dendrites, some containing HRP reaction product, identifying them as dendrites of corticothalamic projection neurons. The highest densities of immunogold particles following glutamate immunostaining were found over such axon terminals and over similar axon terminals devoid of HRP reaction product. In serial sections immunoreacted for GABA, these axon terminals were unlabelled, whereas other axon terminals, establishing symmetric (Gray type II) synapses were heavily labelled. Cell bodies of putative pyramidal neurons, containing retrograde HRP label, were numerous in layers V–VI; some were also present in layers I–III. Most were overlain by high densities of gold particles in glutamate but not in GABA immunoreacted sections. These findings provide evidence that the terminals of projection neurons make synaptic contact with dendrites and dendritic spines in the ipsilateral retrosplenial granular cortex and that their targets include the dendrites of presumptive glutamatergic corticothalamic projection neurons.     

Ultrastructural parameters of GABA-ergic and non-GABA-ergic synaptic contacts on neurons of the catsubstantia nigra

Nigrothalamic neurons were identified in the reticular part of thesubstantia nigra using labelling by the retrograde axonal transport of horseradish peroxidase. Nine parameters of the synaptic contacts (n=195) were analyzed, including the size and shape of terminals and size and type of synaptic vesicies. Sixty-six percent of axon terminals studied formed symmetric contacts and contained large polymorphic vesicles (group I). Two-thirds of these synapses were located on the distal dendrites, while one-third was distributed on the perikarya and proximal dendrites. Synapses of group II (29% of all synapses analyzed) exhibited asymmetric contacts and contained round agranular vesicles. Among these synapses, 79% were located on the distal dendrites, 19% were located on the proximal dendrites, and only 2% were located on the neuronal perikarya. Axon terminals of group III (5% of total population) exhibited symmetric contact and contained small polymorphic vesicles. High-resolution immunogold EM histochemistry indicated that 63% of the group-I axon terminals were GABA-positive. The majority of synapses on the labelled nigrothalamic neurons (21 contacts of 25) belonged to group I. Among these 21 synapses, 19 were axo-somatic and mostly GABA-positive. Within group II, 30% of synapses showed slightly expressed GABA-positivity.Neirofiziologiya/Neurophysiology, Vol. 27, No. 2, pp. 147–157, March–April, 1995.     

Morphological and functional organization of ON and OFF pathways in the adult newt retina

Morphological and functional organization of ON and OFF pathways in the adult newt retina were examined by intracellular recording and staining techniques and immunohistochemistry. Synaptotagmin immunoreactivity discriminated three broad bands within the IPL: the distal band (sublamina I), the middle band (sublamina II) consisting of two dense punctate bands (sublaminae II(a) and II(b)), and proximal band (sublamina III). The Lucifer-yellow labeled OFF amacrine and ganglion cells send their processes mainly in sublamina I and/or II(a) where OFF bipolar cells extend their axon terminals, while ON amacrine and ganglion cells send their processes in sublamina III and/or II(b) where ON bipolar cells extend their axon terminals. Processes of ON-OFF amacrine and ganglion cells ramify broadly in the whole thickness of the IPL. Many bipolar cells responded to light spot with a transient hyperpolarization at both light onset and offset. They are probably subtypes of ON bipolar cells, because their axon terminals branch mainly in sublaminae III and/or II(b), although a few cells ramified the axon at both sublaminae II(a) and III. Two immunohistochemical markers for bipolar cells, PKC and RB-1, identified axon terminals in sublaminae III and/or II(b). From the ramification pattern of axon terminal, they are probably subtypes of ON bipolar cells. ChAT-ir amacrine cells ramified their dendrites in either sublamina I or II(b). Altogether, present studies support the general idea of segregation of ON and OFF pathways in sublaminae a and b of the IPL.     

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.     

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.     

Preproenkephalin-like immunoreactive and calcium-binding proteins-like immunoreactive double-labelled neurons in the spinal trigeminal nucleus caudalis of the rat

Immunofluorescence histochemical double-staining for preproenkephalin (PPE) and calbindin-D28k (CB), calretinin (CR) or parvalbumin (PV) were performed in the spinal trigeminal nucleus caudalis (Vc) of the rat. Neuronal cell bodies exhibiting PPE-like immunoreactivity were present in all laminae of the Vc, with a higher concentration in lamina II. Most of the CB-, CR- and PV-like immunoreactive neurons were located in lamina II, and some of them were also found in laminae I and III of the Vc. Some PPE-like immunoreactive neurons also showed CB-, CR-, or PV-like immunoreactivities. CB/PPE, CR/PPE and PV/PPE double-labelled neurons were mainly observed in lamina II. The percentages of CB/PPE double-labelled neurons in the total numbers of the CB- and PPE-like immunoreactive neurons were 3.5–1.5% and 3.3–15.7%, respectively. Of all CR- and PPE-like immunoreactive neurons, 4.7–13.5% and 3.7–14.2% showed both CR- and PPE-like immunoreactivities. The ratios of PV/PPE double-labelled neurons in all PV- and PPE-like immunoreactive neurons were 9.7–28.1% and 2.1–8.7%, respectively. The present results indicate that some enkephalinergic neurons in the Vc of the rat also contain calcium-binding proteins.     

神经激肽-1(NK-1)受体介导福尔马林诱发的大鼠脊髓c-fos表达

本文用Ｆｏｓ作为背角伤害性反应神经元活动的一个标志物,结合免疫细胞化学和神经药理学方法,观察了速激肽受体拮抗剂对福尔马林诱发的脊髓ｃ－ｆｏｓ原癌基因表达的影响。一侧大鼠后肢跖部皮下注射福尔马林,仅在同侧脊髓背角有ｃ－ｆｏｓ表达。Ｆｏｓ阳性神经元最密集分布于Ｉ层和Ⅱ层背侧的内侧部,中等量分布于Ⅳ层和Ｖ型,少量定位于Ⅱ层腹侧部、Ⅲ、Ⅵ和Ⅹ层。若预先在一侧大鼠后肢跖部皮下注射福尔马林前,鞘内给予神经激肽     

Immunocytochemical research on mediators of centrifugal visual neurons in lampreys (Lampetra fluviatilis)]

The aim of this study has been to investigate different neuroactive substances in the lamprey centrifugal visual neurons (CVN) by combining axonal tracing methods and immunocytochemistry. The CVN somata are immunonegative to antibodies recognizing FMRF-amide, LH-RH, 5 HT and TH, but immunopositive to an anti-GABA antiserum (GABA+) in a proportion of 40%. In the retina, the GABA+ axon terminals mainly synapse upon GABA+ and GABA- amacrine cell bodies and dendrites, and on dendrites of GABA- ganglion cells.     

Effects of systemic administration of strychnine, L-allylglycine, bicuculline and picrotoxin on the transsynaptic neural destruction in the medullary dorsal horn following transection of the rat inferior alveolar nerve

Adult rats underwent unilateral transection of the inferior alveolar nerve and subsequent intraperitoneal injection of strychnine (1 mg/kg, 3-23 days) at various posttransectional intervals. When they were sacrificed at 18-30 days posttransectionally, many pyknotic neuronal cell bodies were observed in plastic embedded toluidine blue-stained 1 micron-thick sections of the medullary dorsal horn. They were mostly found in the dorsal part of the dorsal horn ipsilateral to the neurotomy and were more abundant in laminae I/II than in laminae III/IV. Similar pyknotic neurons were found after 1 or 2 days of L-allylglycine administration (55.7 mg/kg/day) at a posttransectional interval of 20 days. Unlike those observed after strychnine treatment, the pyknotic neurons after L-allylglycine treatment were evenly distributed throughout laminae I-IV of the dorsal half of the medullary dorsal horn. Twenty-three days of bicuculline (2 mg/kg/day) or picrotoxin (0.5 mg/kg/day) treatment at an interval of 7 days did not yield pyknotic neurons. The results are discussed in the light of intrinsic synaptic circuitry of the dorsal horn.     

The colocalization of neurotransmitters in the presynaptic boutons of inhibitory synapses in the lamprey spinal cord]

Using the electron microscopy immunocytochemistry, the GABA and glycine immunoreactivity was studied in presynaptic axon terminals of the spinal cord central gray in the lamprey Lampetra fluviatilis. All immunopositive presynaptic terminals contacting motoneurones or non-identified post-synaptic profiles were divided into only GABA- (44%), only glycine-immunopositive terminals (26%), and both GABA- and glycine-containing terminals (30%). The glycine-immunopositive axon terminals contained flattened synaptic vesicles. Large dense core vesicles were co-localised with conventional synaptic vesicles in 74% of GABA-containing presynaptic terminals.