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C E Hulsebosch

Publications and source records attributed to C E Hulsebosch.

At least 55 records · Page 3Linked to original sources
PubMed1991

Differential effects on sensory nerve processes and behavioral alterations in the rat after treatment with antibodies to nerve growth factor.

Published work on the effects of antibodies to nerve growth factor (ANTI-NGF) treatment on rats has shown an increase in the number of unmyelinated central processes of dorsal root ganglia (DRG) neurons (31). This increase is interpreted to be sprouting of the central projections of the DRG neurons. To test for sprouting of the peripheral DRG projections, we quantitated the number of peripheral DRG processes in the peripheral nerves of ANTI-NGF-treated compared to untreated rats, following selective surgery to eliminate motor and sympathetic nerve fibers. We report the numbers of peripheral DRG processes in an NGF-deprived environment decrease by 48% compared to untreated controls and the decrease is selective for the unmyelinated fiber population. Since the majority of the unmyelinated population is nociceptive, two nociceptive behavioral measures, one reflexive (tail flick) and one nonreflexive (paw or skin pinch), were performed and demonstrated decreased responses in the ANTI-NGF-treated compared to untreated and preimmune-treated rats. These data suggest a directional effect, primarily on the unmyelinated sensory population which results in altered nociceptive behavior, induced by the suppression of one endogenous factor, NGF. Furthermore, it is important to note that the centrally directed sensory processes project to a central nervous system environment and the peripherally directed processes are in a peripheral nervous system environment. Thus, a single molecule may have different effects on directional growth of a neuronal population that may be related to the interactions available in the substrate of the environment.

Animals↗
PubMed1991

Intraspinal sprouting of calcitonin gene-related peptide containing primary afferents after deafferentation in the rat.

The occurrence of sprouting in the spinal cord in response to denervation has been a subject of debate. To test for sprouting of primary afferent fibers after denervation, rats were unilaterally deafferented for 35 days (chronic side) by dorsal rhizotomies performed from T2 to T8 and T10 to L5, thus isolating or sparing the T9 root. The contralateral T9 root was spared by a similar surgery 5 days (acute side) prior to sacrifice. The survival time on the chronic side presumably allows intraspinal sprouting of T9 primary afferents to occur whereas the time on the acute side does not. To test for sprouting of primary afferents, it is necessary to identify these nerve processes. Calcitonin gene-related peptide (CGRP) immunoreactivity has been localized to a subpopulation of primary afferent nerve processes and their terminals within the dorsal horn. Therefore, immunohistochemical methods were used to determine the distribution of CGRP immunoreactivity in laminae I and II on both sides of the spinal cord. Using image analysis, there was an increase of 153 to 704% in the density of CGRP immunoreaction product on the chronic side compared to the acute side in the spared segment. This difference is statistically significant. Furthermore, the increased density on the chronic side extended two segments cranial and two segments caudal to the spared root segment. No difference was found in the laminar distribution between sides. These data support the hypothesis of primary afferent sprouting following spinal cord denervation.

Animals↗
PubMed1990

In vivo recovery of Schwann cell-neuronal interactions altered by nerve growth factor suppression in the rat.

Recovery of Schwann cell-neuronal interactions altered by suppression of endogenous nerve growth factor (NGF) with antibodies to NGF (anti-NGF) was determined by morphometric analysis of unmyelinated and myelinated sensory fibers in the T9 dorsal roots in 3 groups of animals: (1) rats one week after cessation of anti-NGF treatment (anti-NGF + 1WK), (2) rats given antibodies to NGF (anti-NGF) and (3) untreated same age littermates (UNTR). The results indicate that (1) recovery of normal myelination begins within one week of cessation of anti-NGF treatment for small caliber fibers and (2) the observed results of anti-NGF treatment on Schwann cell-neuronal interactions were due to anti-NGF treatment and were not an indirect effect of a general diseased state.

Animals↗
PubMed1990

Denervation-induced intraspinal synaptogenesis of calcitonin gene-related peptide containing primary afferent terminals.

The purpose of the present study is to provide evidence that chronic spinal denervation leads to an increase in numbers of synaptic terminals from a specific population of primary afferent fibers. Rats were unilaterally deafferented for 35 days (chronic denervation) by dorsal rhizotomies performed from T2 to T8 and T10 to L5, which isolates or spares the T9 root. The contralateral T9 root was spared by similar surgery 5 days (acute denervation) prior to sacrifice. The survival time on the chronic side presumably allows sprouting of T9 primary afferents to occur, whereas the time on the acute side does not. The terminals were labeled with calcitonin gene-related peptide (CGRP), which is a compound that labels a specific population of primary afferent fibers and terminals, and stereological methods were used to determine the numbers of immunolabeled terminals in laminae I and IIo on the chronic and acute sides of the T9 spinal cord. The findings are that the chronic side had approximately twice as many terminals as the acute side. This difference is statistically significant. These findings are compatible with the hypothesis that chronic denervation leads to synaptogenesis from surviving primary afferent fibers.

Animals↗
PubMed1990

Schwann cell-neuronal interactions in the rat involve nerve growth factor.

To gain some insight into possible functions of nerve growth factor (NGF), we suppressed the endogenous levels of NGF in newborn rats by subcutaneous injections (3 microliters/g body weight) of rabbit antibodies to purified mouse beta-NGF (ANTI-NGF). Fiber and axonal areas and perimeters were measured for unmyelinated and myelinated sensory fibers in T9 dorsal roots (DR) in three groups of animals: 1) ANTI-NGF treated littermates, 2) preimmune sera treated littermates (PREIMM), and 3) untreated littermates (UNTR). In some rats, fibers in ventral roots (VR) were measured and, in other rats, sensory processes in peripheral nerves (PN) were measured following radical ventral rhizotomy. The only outer area and perimeter measurements that were statistically different were those in the ventral root (P less than 0.013 and P less than 0.043, respectively). However, myelin thickness was significantly thinner in the dorsal roots of the ANTI-NGF group than in the dorsal roots of the UNTR and PREIMM groups (P less than 0.000009 and P less than 10(-6), respectively). Myelin thickness in the ventral roots of the ANTI-NGF group was also statistically thinner than that in the UNTR group (P less than 0.001). There were no statistically significant differences when comparing the UNTR group to the PREIMM group. In the peripheral nerves studied, there was no significant change in the myelin thickness between the ANTI-NGF and UNTR groups of animals. These results indicate that Schwann cell-neuronal interactions are altered by the inactivation of NGF, and that 1) the central processes of sensory fibers are affected and not the peripheral processes and 2) motor fiber myelination is altered.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Computerized ultrastructural analysis of the shape of the active synaptic zones in rat spinal cord.

Active synaptic zones are cytoplasmic specializations that indicate where synaptic transmission occurs. We have used computerized three-dimensional reconstructions from serial ultrathin sections to define certain features of the geometry of these zones in mammalian spinal cord. Our main finding is that the active zones in the dorsal portion of the spinal cord can be placed in one of two categories with respect to curvature: (1) uncurved or slightly curved and (2) very curved. The very curved category is associated with simple axodendritic type synapses in which the axonal terminal arises from primary afferent fibers.

Animals↗
PubMed1989

Changes in dorsal horn synaptic disc numbers following unilateral dorsal rhizotomy.

The present study estimates the numbers of synaptic discs and numbers of degenerating synaptic terminals in laminae I-IV of the rat S2 dorsal horn ipsi- and contralateral to unilateral dorsal rhizotomy. These data allow us to estimate the loss of synapses of primary afferents and to correlate this loss with the rate of axon disappearance in the proximal stump of a transected S2 dorsal root. Our first findings are that 47% of the ipsilateral synapses and 27% of the contralateral synapses disappear within a day following unilateral rhizotomy. Conclusions are that the predominant synaptic population in this part of the rat spinal cord is of primary afferent origin and that there is an extensive bilateral projection of the dorsal root fibers. The contralateral projection is confirmed by the appearance of numerous degenerating terminals on the contralateral side. We also find that synaptic loss and appearance of degenerating terminals occur relatively synchronously in laminae I-IV. Finally we find that the time course of the synaptic loss correlates primarily with the disappearance of unmyelinated fibers in the proximal stump of the transected dorsal root.

Animals↗
PubMed1989

Penetration of IgGs into the neuraxis of the neonatal rat.

The permeability of the mammalian blood-brain barrier to macromolecules during prenatal and postnatal development is a controversial issue. We tested the possible access of xenogeneic antibodies to the neuraxis by examining neural tissue of neonatal rats 48 h after intraperitoneal injection of rabbit IgGs, using a modification of the peroxidase-antiperoxidase (PAP) technique. The results of the present study indicate diffuse immunoreactivity for rabbit IgGs in the parenchyma in all regions of the neuraxis in neonatal rats. This work suggests that immunoglobulins, both maternal and isogeneic, may affect the nervous system during prenatal and postnatal development.

Animals↗
PubMed1989

Time course of penetration of xenogeneic IgG into the central nervous system of the neonatal rat: an immunohistochemical and radionuclide tracer study.

We investigated the penetration of rabbit IgG into the brain and spinal cord of newborn rat pups and compared them to mature rats using immunohistochemical and radionuclide techniques. Following intraperitoneal injection with rabbit IgG and perfusion fixation at various intervals, rabbit IgG was found to penetrate into the parenchyma of the neuraxis of neonatal rats and to establish much higher concentrations than was found in mature rats. Immunohistochemical studies revealed no evidence of significant extravasation of serum proteins from the vasculature. For any given survival interval studied, there was no significant difference in appearance and intensity of immunohistochemical staining or the amount of radiolabeled IgG measured between different areas of the brain and spinal cord. Electrophoresis of radioactive proteins extracted from the brains of neonatal rats injected with radiolabeled IgG confirmed that IgG penetrates into the brain parenchyma as the whole molecule. These results validate the use of systemically administered rabbit IgG for studies of brain development in neonatal rats. They also have implications for the pathogenesis of congenital central nervous system anomalies in which maternal autoimmune IgG may affect brain development after being transferred to the fetus or neonate.

Animals↗
PubMed1988

Numbers of synapses in laminae I-IV of the rat dorsal horn.

The present study determines numerical densities (NVsyn) and total numbers of synaptic discs in laminae I-IV of the rat S2 dorsal horn. Previous methods for NVsyn have the advantage of being relatively simple, but these assume that the discs are round, flat, and of uniform size. In our material, serial reconstructions indicate that these assumptions are not met. Accordingly we use a stereological method that is not as dependent on these assumptions. This method is to divide the surface density of the discs by the mean surface area of a disc (NVsyn = SVsyn/Ssyn). We refer to this as a reconstruction method because synaptic discs are reconstructed from serial sections. We also calculate numerical densities by several previously used standard methods, and the findings are similar but not identical. We find that numerical density and total synaptic numbers are smallest in lamina I, and densities and total numbers are not significantly different when lamina II is compared to laminae III and IV. Thus the intense labeling of terminals with certain compounds that characterize lamina I and II does not imply an increase in total synaptic numbers or in synaptic density. In addition there is a general increase in synaptic densities and numbers as one proceeds from lamina I to lamina IV. Another point is that the numerical density of synapses in the dorsal horn is approximately that of the cerebral cortex. These data will serve as a basis from which to judge the effects of denervations and other manipulations that purportedly change synaptic numbers.

Animals↗
PubMed1988

Intraspinal sprouting after administration of nerve growth factor antibodies to neonatal rats.

Previous observations show that neonatal removal of nerve growth factor results in an increased number of fine dorsal root axons in the adult animal. The present study shows that the same treatment results in 49% more axons in the adult tract of Lissauer, which is an area of spinal white matter that contains predominantly fine primary afferent axons. These data are consistent with the idea that postnatal removal of NGF leads to increased numbers of fine primary afferent axons which then pass into the white matter of the spinal cord and there make synaptic contacts. If so, this would be a useful preparation for studies on the mechanisms by which newly formed sensory axons can be induced to enter the spinal cord postnatally.

Animals↗
PubMed1987

Intraspinal sprouting of rat primary afferents after deafferentation.

To test intraspinal sprouting of primary afferent fibers, unilateral chronic, followed by contralateral acute, dorsal rhizotomies were done 3 segments above and below a spared segment (T9) in rats. Following perfusion with 4% paraformaldehyde, T9 spinal cord segments were frozen, sectioned and reacted by a modified Gomori procedure for fluoride-resistant acid phosphatase (FRAP) enzyme activity, a marker for primary afferent terminals. As determined by light microscopy, there was greater and extended FRAP reaction product in laminae I and II on the chronically denervated side than on the contralateral acutely denervated side. These data support the hypothesis of axonal sprouting and synaptogenesis of primary afferent fibers after spinal cord deafferentation.

Afferent Pathways↗
PubMed1987

Persistence of anti-NGF induced dorsal root axons: possible penetration into the mammalian spinal cord.

Neonatal rats were given daily injections of antisera to nerve growth factor protein (anti-NGF) for a period of 1 month and then allowed to survive 17 more months. The number of neurons in dorsal root ganglia (DRG) and axons in the dorsal root (DR) were determined in the anti-NGF rats and compared to similar numbers from untreated littermates. We found a 32% decrease in DRG neuron number and 32 and 34% increases in myelinated and unmyelinated DR fibers, respectively, in the anti-NGF rats. The sensory cell bodies in the anti-NGF rats were on the average 23% larger than in the normal rats. We conclude that in an NGF deprived environment a population of DRG neurons dies, principally the small neurons, and in response the surviving neurons emit extra processes which persist for most of the life of the rat. This suggests that the anti-NGF induced axons enter the spinal cord and synapse.

Animals↗
PubMed1987

In vivo ANTI-NGF induces sprouting of sensory axons in dorsal roots.

Newborn rats were given subcutaneous injections of antibodies to mouse beta -NGF (ANTI-NGF) daily for 1 month. The number of neurons in T4-T6 dorsal root ganglia (DRG) and the numbers of myelinated and unmyelinated axons in the dorsal roots of the same segments were counted in the ANTI-NGF animals and in normal littermates. The ANTI-NGF rats had 38% fewer neurons in thoracic ganglia but 17% more myelinated and 40% more unmyelinated fibers than their untreated littermates. Dorsal root ganglion cells also have a larger average size in the ANTI-NGF animals, which we interpret as a disproportionate loss of small cells. These data are interpreted as showing that some dorsal root ganglion cells, principally small ones, die when endogenous NGF is inactivated, and that the remaining cells emit more processes than normal. Thus, removal of NGF has what appears to be a paradoxical effect, a reduction in dorsal root ganglion cell numbers but an increase in dorsal root axon numbers. The relation of myelin thickness to fiber diameter is also altered, with small fibers being more thinly myelinated in the ANTI-NGF group. Thus, Schwann cell-neuronal interactions are also affected by inactivation of NGF.

Animals↗
PubMed1986

Axon and neuron numbers after forelimb amputation in neonatal rats.

It seems a paradox that more primary sensory neurons are lost but recovery is better after peripheral nerve injury in neonates as compared to adult mammals. A possible explanation is that surviving neurons sprout in the neonate. To test this, forelimbs in neonatal rats were amputated, which caused the death of many primary sensory neurons. The number of neurons in the dorsal root ganglia, and the number of myelinated and unmyelinated fibers in the dorsal and ventral roots were determined on the amputated and contralateral normal sides. On the amputated side, soma loss in the ganglia was 30%, and the fiber numbers were decreased by 16% in the dorsal root and increased by 20% in the ventral root. These data are compatible with the hypothesis that there is axonal branching or sprouting from surviving sensory neurons. In addition, morphometric analyses showed a changed myelin-axon relationship for central processes of sensory cells whose distal processes have been cut.

Amputation, Surgical↗
PubMed1986

Numbers of rat dorsal root axons and ganglion cells during postnatal development.

The present study demonstrates that T4 and S2 rat dorsal root axons decrease significantly from birth to adulthood with almost all of the decrease occurring in the first two weeks of life. Dorsal root ganglion cell numbers do not change during this time period. This is thus an example of postnatal axon elimination not associated with death of the cells that give rise to the axons. Presumably this regressive process is important in the formation of the normal adult nervous system. In addition, these findings raise the possibility that certain types of neonatal denervation may increase adult axon numbers by stopping a regressive process, the loss of axons, rather than initiating a progressive process, the formation of new axons.

Animals↗
PubMed1985

Sexual dimorphism in the numbers of neurons in the pelvic ganglia of adult rats.

The major pelvic ganglion in the adult rat differs in neuron number in the two sexes. The female pelvic ganglion has 5892 +/- 797 (mean +/- S.D.) neurons while the male contains 14,654 +/- 936. This sexual dimorphism in neuronal numbers in the autonomic nervous system is of interest because it suggests that endogenous hormone levels during development may have an influence on numbers of neurons in the adult pelvic ganglion.

Animals↗