摘要:

AbstractUsing immunocytochemistry we have identified important differences in the distribution of immunoreactive dynorphin and enkephalin cells and terminals in the trigeminal nucleus caudalis and in the spinal dorsal horn of the cat. Dynorphin immunoreactive processes are more closely associated with those regions of cord that process nociceptive information, specifically laminae I and V. Enkephalin neurons and terminals are more widespread. Based on the staining pattern with an antiserum to the octapeptide‐met‐enkephalin‐arg‐gly‐leu, we suggest that the dense enkephalin terminal immunoreactivity in the inner part of the substantia gelatinosa derives from cells in lamina III. There are also significant differences in the anatomical relationship of the two opioid peptides with the organization of parasympatheic autonomic preganglionic neurons. The functional significance of these observations must await physiological analysis; nevertheless, it is almost certain that differences will be found and that these will be important in understanding the mechanisms through which exogenous opiates and a variety of descending control systems exert their effects on spinal cor

ISSN:0092-7317    

DOI:10.1002/cne.902400402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractRetrograde transport of lectin‐HRP conjugate (WGA‐HRP) was used to examine the anatomical organization of long ascending propriospinal neurons (LAPNs) projecting to the cervical enlargement (C5‐T1) and to the upper part of the cervical cord (C3‐4) in cats. Small injections (0.05–1.0 μl) of dilute (1–4%) WGA‐HRP were made into the C5‐T1 or C3‐4 regions. The field potential evoked from stimulation of the superficial radial nerve served to position the micropipette delivering injections. Small and localized populations of labelled LAPNs were found in the dorsal horn (laminae IV‐V), the intermediate zone (dorsal and medial lamina VII), and the ventral horn (ventral lamina VII, laminae VIII and IX). Ventral horn LAPNs projecting to the C5‐T1 region were preferentially located in rostral lumbar regions. Ventral LAPNs projecting to the C3‐4 region were more caudally situated. No regional differences in distribution of dorsal horn and intermediate zone LAPNs were noted in comparing the results of C3‐4 with C5‐T1 injection protocols. It is concluded that the caudally located ventral LAPNs may exert their influence on cervical motor output through C3‐4 propriospinal inter‐neurons. Other LAPNs are considered to exert their effect more directly, either

ISSN:0092-7317    

DOI:10.1002/cne.902400403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractFive intracellularly HRP‐stained Renshaw cells were subjected to light microscopic analysis of the trajectories, branching patterns, and projections of the axonal systems.The cell bodies were located ventrally in lamina VII. In three neurons the axon originated from the cell body and in the remaining two cells from a dendrite. After a 600–870‐μm distance the axons entered the ventral funiculus, where all of them continued rostrally. Two axons also gave off a caudal branch in the funiculus. The diameters of the main axons varied between 2.1 and 10.0 μm.The main axons gave off one to four first‐order collaterals before entering the ventral funiculus and up to three collaterals could be seen to originate from the same node of Ranvier. In the ventral funiculus up to five first‐order collaterals could be traced from the same main axon. The axon collateral trees were often very extensive and daughter branches up to the 22nd order were observed. The distance between two successive branching points varied between 4 and 410 μm. A large number of boutonlike swellings were found along (59%) or at the ends of the collateral branches. At the most, 1,278 swellings originated from a single axon collateral tree. Most of the swellings were located in lamina IX, but they also appeared ventrally and dorsolaterally i

ISSN:0092-7317    

DOI:10.1002/cne.902400404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe cell bodies and dendritic trees of five lumbosacral Renshaw cells of adult cats were studied in the light microscope (LM) after intracellular injection with horseradish peroxidase (HRP).The cell bodies were all located in the ventral part of lamina VII. The dendrites extended up to 0.7 mm from the cell body into the neighbouring parts of laminae VIII and IX as well as into more dorsal parts of lamina VII. The dendritic branching was sparse and about half the dendrites were unbranched. The mean diameter of the cell body was positively correlated to both the combined and mean diameters of the first‐order dendrites. Between four and eight dendrites originated from the cell bodies.The number of dendritic endbranches, the combined dendritic length, the mean dendritic length from the cell body to the termination of the end branches, the distance from the cell body to the termination of the most remote end‐branch, the dendritic surface area, and the dendritic volume all correlated positively with the diameter of the parent first‐order dendrite. The dendritic tapering was somewhat more pronounced in the Renshaw cells than previously observed in α‐ and γ‐motoneurons. The present data are discussed in relation to previous morphological observations on Renshaw cells and α‐ and

ISSN:0092-7317    

DOI:10.1002/cne.902400405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe process of transganglionic transport was used to determine the pattern of primary afferent projections to the spinal cord and brainstem in the pigeon by (1) applying horseradish peroxidase (HRP) to various peripheral nerves in the leg or wing, (2) by injecting HRP‐lectin into feather follicles of the wing or tail, and (3) by injecting HRP‐lectin into various muscles of the leg or wing.In the spinal cord major peripheral nerves were represented heavily throughout the dorsal horn laminae but sparsely in more ventral laminae. The representations of these different nerves tended to be located in different mediolateral regions of the dorsal horn. Cutaneous nerves and feather follicles were represented predominantly in laminae I and II, and different sets of follicles were represented in different mediolateral regions of these laminae. Afferent labelling from muscles of the leg and wing was located in the lateral portion of the dorsal horn, predominantly in laminae I, II, and IV.In the caudal medulla the representation of the leg within the gracile nucleus was medial to and separate from that of the wing within the cuneate nucleus (Cu). The wing representation, however, extended laterally throughout the external cuneate nucleus (CuE) and lateral regions of the descending trigeminal tract. There was less evidence of separation of the limb representations at more rostral medullary levels where they both occupied predominantly CuE. Afferent labelling from cutaneous nerves and feather follicles was distributed lightly throughout Cu and CuE, and from muscles of both limbs primarily throughout CuE. There was also a small but specific projection from the limbs to the nucleus of the solitary tract, and from the wing to the principal sensory trigeminal nucleus.These results are discussed within a comparative context with a view to highlighting the similarities and differences in the pattern of primary afferent central projections in different vertebra

ISSN:0092-7317    

DOI:10.1002/cne.902400406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractRabbit retinae were double labeled to determine the degree of colocalization of glutamic‐acid‐decarboxylase‐like immunoreactivity (GAD‐like IR) and3H‐GABA uptake using light (LM) and electron microscopic (EM) auto‐radiography. Both GAD‐like IR and3H‐GABA uptake were found in amacrine cell bodies in the inner nuclear layer (INL) as well as in cell bodies in the ganglion cell layer (GCL), and throughout the inner plexiform layer. GAD‐like IR was found in 32% of the amacrine cells in the INL, 86% of which also showed3H‐GABA uptake;3H‐GABA uptake was observed in 38% of the amacrine cells. However, only 72% of these cells showed GAD‐like IR. Labeled cells in the GCL were only 10–15% as common as similarly labeled cells in the INL. As in the INI., all GAD‐positive cells in the GCL were double labeled, but only 53% of the cells taking up3H‐GABA were double labeled. We suggest that labeled cells in the GCL were ganglion cells rather than displaced amacrine cells. Cells, in both the INL and GCL, that showed3H‐GABA uptake but no GAD‐like IR had a higher average grain density than double‐labeled cells, indicating that uptake by these cells was specific. The relevance to GABAergic function of3H‐GABA uptake without an indication of GAD‐like IR is yet to be determined. Statistical analysis at the EM level showed that one‐third of the GAD‐positive synaptic terminals of amacrine cells were double labeled after a 4‐month exposure. Longer exposures at the EM level should reveal a higher percentage of GAD‐positive terminals because at the LM level, one‐half of the double‐labeled cell bodies were “lightly” labeled with grains. The high degree of colocalization of GAD‐like IR and3H‐GABA uptake suggests that both markers may be

ISSN:0092-7317    

DOI:10.1002/cne.902400407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTransganglionic labelling of the saphenous nerve in rats with WGA‐HRP revealed the central distribution of its terminals in the lumbar dorsal horn. The terminal field was clearly defined and consistent in rats aged between day 6 and day 90. If, however, the sciatic nerve was sectioned on day 1 of postnatal life, the saphenous terminal field expanded to occupy twice the normal area (measured between the L2 and L4 boundaries). The spread was caudal, medial, and lateral into areas normally occupied by sciatic nerve terminals. This sprouting was very weak if the sciatic nerve was sectioned later in postnatal life, on day 5, and nonexistent if sectioning took place on day 10. Crushing the sciatic nerve on day 1 also triggered the effect but the spread of the terminal field was less than that produced by section of the sciatic nerve. There was no evidence of sprouting from the contralateral intact sciatic nerve. The results demonstrate the necessity of intact afferent input during a critical period of neonatal life in order to maintain the precise somatotopic termination pattern of dorsal root afferent

ISSN:0092-7317    

DOI:10.1002/cne.902400408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractPeripheral nerve section results in depletion of fluoride‐resistant acid phosphatase (FRAP) from the nerve terminals in the dorsal horn of the spinal cord (Schoenen et al., '68) and this has been used in the past to map the termination field of individual nerves (Rustioni et al., '71; Devor and Claman, '80). In the present study we show that a similar central depletion occurs following sciatic nerve section or crush in neonatal rats. Unlike adults, however, the area of depletion is rapidly filled by sprouting of FRAP‐containing afferent terminals from nearby intact peripheral nerves. The sprouting is extensive but never completely fills the depleted area. After nerve crush there is some recovery of FRAP from the sciatic nerve terminals themselves as well as from nearby nerve terminals. The source of recovered FRAP is demonstrated by resectioning or recrushing the nerves. The sprouting occurred when the sciatic was injured on day 1 but failed to take place when the injury was applied on or after day 10.Sciatic nerve section on day 1 also produces marked growth retardation of the ipsilateral dorsal horn gray matter that becomes more apparent as the rat matures. Nerve crush produces a less marked shrinkage that is slower in onset. If the nerve is crushed repeatedly, however, so that regeneration is prevented, the shrinkage is analogous to that following nerve section. No shrinkage occurs if the nerve is cut or crushed on day 10.The results show that separation of the spinal cord from its peripheral input at a critical stage in development results in disruption of the somatotopic organization of the C fibre afferent input to the dorsal horn and in slowing of growth of the dorsal horn gray mat

ISSN:0092-7317    

DOI:10.1002/cne.902400409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractElectron microscopic observation of the distal retina of the turtle,Chelydra serpentinarevealed that photoreceptors contact each other by means of a variety of junctions. The synaptic terminals of the primary and accessory members of a double cone invariably make punctate contact with each other distal to the basal surfaces. This type of contact was only rarely seen between the synaptic terminals of single photoreceptors. Photoreceptor telodendria which emanate from the basal surface of the synaptic terminal and ramify laterally for up to 40 μm in the outer plexiform layer give off branchlets which contact the terminals of both rods and cones. These contacts resemble superficial basal junctions and can be of the “wide‐gap” or “narrow‐gap” type. In cones the branchlets of the telodendria sometimes make a “distal junction” with one of the lateral elements of a synaptic dyad. Gap junctions were not found between the fins radiating from the myoids of adjacent receptors but were seen to occuren passantbetween photoreceptor telodendria in the outer plexiform layer. These junctions, though small, are probably of sufficient size to account for the rod‐rod coupling observed physiologically in this retina.A prominent organelle resembling a synaptic lamella was occasionally seen in processes making contact with photoreceptors. These processes were identified as bipo

ISSN:0092-7317    

DOI:10.1002/cne.902400410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902400401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY