Biomedical subjects

B Ulfhake

Publications and source records attributed to B Ulfhake.

At least 55 records · Page 3Linked to original sources

PubMed1992

Reappearance of calcitonin gene-related peptide-like immunoreactivity in the dorsal horn in the long-term dorsal root transected rat.

Calcitonin gene-related peptide (CGRP)-immunoreactive (IR) fibers in the rat dorsal horn superficial laminae vanish almost completely 3 weeks following unilateral dorsal rhizotomy. After a prolonged survival (20 weeks) of dorsal rhizotomy there is, however, a reappearance of CGRP-IR fibers in the corresponding laminae of the dorsal horn. The density of such IR fibres showed a clear gradient with the lowest number found in the midlesion region and an increase in density towards the neighboring, intact segments. In normal as well as lesioned rats, no neurons intrinsic to the dorsal horn contained detectable levels of CGRP-like immunoreactivity (LI). Furthermore, no cells could, by use of in situ hybridization, be demonstrated to contain detectable levels of mRNA encoding for CGRP in the dorsal horn. Based on these findings, we suggest that the CGRP-IR fibers observed following long-term survival of dorsal rhizotomy derive from proliferating collateral branches of primary afferents of neighboring intact segments.

Animals↗

PubMed1992

Anatomy of dendrites in motoneurons supplying the intrinsic muscles of the foot sole in the aged cat: evidence for dendritic growth and neo-synaptogenesis.

Motoneurons (MNs) supplying the intrinsic muscles of the foot sole (IFS) were studied in the aged cat (greater than 15y). Axon conduction velocity of IFS MNs was 30-40% slower in the aged than in young adult cats. IFS MNs that appeared intact during intracellular recordings and labeling with horseradish peroxidase (HRP) were subjected to anatomical investigation of their dendrites. The results were compared with corresponding data from young adult (less than 3y) cats. The average number of dendrites per IFS MN was twelve in both the aged and young adults. However, the branching was significantly more extensive in the aged cat, thus indicating that proliferation of dendritic branches may occur during the later part of life. Topological analysis revealed a significant difference in the frequency distributions of nodal vertices between young adult and aged cats. In the young adult, the dendritic branching pattern was compatible with trees generated by outgrowth from terminal segments, while in the aged there was a clear indication of collateral outgrowth of branches. The dendritic path distance and the length of terminal branches were similar in young adults and aged. The length of preterminal branches was shorter in the aged, while the combined dendritic length of a dendrite was larger compared to young adults. These data are consistent with the topological data, and add further evidence that the proliferation of branches in the aged cat may also take place from preterminal branches. Light microscopic analysis revealed the presence of "growth cone-like" extensions in the dendrites of the aged cats. Such profiles were not encountered in dendrites from young adults. Electron microscopic observations showed that these "growth cone-like" formations were not artifacts and that they were apposed by numerous axonal boutons, of which a number made synaptic contact. A distinct feature of the extensions was their rich content of mitochondria and membranous elements. It was suggested that these "growth cone-like" formations were sites at which novel synaptic connections are established, and that they may represent the initial stage of an outgrowth of new dendritic branches in the aged cat. Local dendritic branch diameter related closely to the amount of dendritic membrane area located distally in both young adults and aged. Curve fitting disclosed that this relationship was quite similar for both age groups, despite concurrent differences in combined dendritic length and branching degree.

Aging↗

PubMed1992

Distribution of enkephalin and its relation to serotonin in cat and monkey spinal cord and brain stem.

The distribution of enkephalin (ENK)-like immunoreactivity (LI) in spinal cord and medulla oblongata of cat and gray monkey (Macaca fascicularis) was studied by use of immunofluorescence and peroxidase antiperoxidase (PAP) techniques. Possible coexistence between ENK- and 5-hydroxytryptamine (5-HT)-LI was also analyzed with double labeling immunofluorescence. Furthermore, in situ hybridization was used to demonstrate cell bodies in the brain stem expressing mRNA encoding for ENK. ENK-immunoreactive (IR) axonal varicosities and fibers were demonstrated throughout the spinal cord gray matter, with the highest density in the superficial dorsal horn, the area around the central canal, the intermediolateral cell column, the sacral parasympathetic nucleus, and in Onuf's nucleus. In the monkey ventral horn, ENK-IR varicose fibers could in some cases be demonstrated in very close apposition to cell bodies. A low degree of co-localization between ENK- and 5-HT-LI was seen in the spinal cord of both species. Still, fibers containing both compounds could as a rule be demonstrated in every section studied. The highest degree of coexistence was encountered in the motor nucleus of the ventral horn. Six weeks after a low thoracic spinal cord transection a decreased staining for ENK-LI was demonstrated in the ventral horn motor nucleus, whereas other parts of the spinal cord appeared unaffected. In the brain stem of cats after colchicine treatment, ENK-LI was found in a majority of the 5-HT-IR cell bodies in the raphe nuclei (nucleus raphe magnus, pallidus and obscurus) and in the lateral reticular nucleus (rostroventrolateral reticular nucleus). In cat not pretreated with colchicine, a few weakly stained ENK-IR cell bodies could be found in the midline raphe nuclei and in the lateral reticular nucleus with the PAP technique. In the monkey brain stem without colchicine treatment, using the PAP technique, heavily stained ENK-IR cell bodies could be seen in the lateral reticular nucleus whereas, as in the cat, only a few, weakly stained ENK-IR cell bodies could be seen in the midline raphe nuclei. Using in situ hybridization technique, ENK mRNA expressing cells were demonstrated in the lateral reticular nucleus while no convincing mRNA signal could be found over cell bodies in the raphe nuclei. It is concluded that part of the ENKergic innervation of the cord in both species derives from supraspinal or suprasegmental levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1992

Expression of GAP-43 mRNA in the adult mammalian spinal cord under normal conditions and after different types of lesions, with special reference to motoneurons.

In situ hybridization histochemistry was used to detect cell bodies expressing mRNA encoding for the phosphoprotein GAP-43 in the lumbosacral spinal cord of the adult rat, cat and monkey under normal conditions and, in the cat and rat, also after different types of lesions. In the normal spinal cord, a large number of neurons throughout the spinal cord gray matter were found to express GAP-43 mRNA. All neurons, both large and small, in the motor nucleus (Rexed's lamina IX) appeared labeled, indicating that both alpha and gamma motoneurons express GAP-43 mRNA under normal conditions. After axotomy by an incision in the ventral funiculus or a transection of ventral roots or peripheral nerves, GAP-43 mRNA was clearly upregulated in axotomized motoneurons, including both alpha and gamma motoneurons. An increase in GAP-43 mRNA expression was already detectable 24 h postoperatively in lumbar motoneurons both after a transection of the sciatic nerve at knee level and after a transection of ventral roots. At this time, a stronger response was seen in the motoneurons which had been subjected to the distal sciatic nerve transection than was apparent for the more proximal ventral root lesion. An upregulation of GAP-43 mRNA could also be found in intact motoneurons located on the side contralateral to the lesion, but only after a peripheral nerve transection, indicating that the concomitant influence of dorsal root afferents may play a role in GAP-43 mRNA regulation. However, a dorsal root transection alone did not seem to have any detectable influence on the expression of GAP-43 mRNA in spinal motoneurons, while the neurons located in the superficial laminae of the dorsal horn responded with an upregulation of GAP-43 mRNA. The presence of high levels of GAP-43 in neurons has been correlated with periods of axonal growth during both development and regeneration. The role for GAP-43 in neurons under normal conditions is not clear, but it may be linked with events underlying remodelling of synaptic relationships or transmitter release. Our findings provide an anatomical substrate to support such a hypothesis in the normal spinal cord, and indicate a potential role for GAP-43 in axon regeneration of the motoneurons, since GAP-43 mRNA levels was strongly upregulated following both peripheral axotomy and axotomy within the spinal cord.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗

PubMed1992

Galanin- and CGRP-like immunoreactivity coexist in rat spinal motoneurons.

We can report, that by the use of indirect immunofluorescence techniques, that rat spinal motoneurons contain galanin-like immunoreactivity (LI). Furthermore, that galanin and calcitonin gene-related peptide (CGRP)-LI coexist in a number of spinal motoneurons. Co-localization could be demonstrated as thoracic, lumbar as well as sacral spinal cord levels in individual neurons by studying adjacent sections each stained by one of the two antisera, as well as by double labelling experiments. Small neurons, within the gamma-motoneuron and interneuron size-range, were also positive for galanin-LI.

Aging↗

PubMed1992

Distribution of calbindin D28k-like immunoreactivity (LI) in the monkey ventral horn: do Renshaw cells contain calbindin D28k-LI?

By use of indirect immunofluorescence and peroxidase-antiperoxidase immunohistochemistry, we show that the monkey (Macaca fascicularis) ventral horn harbors small- to medium-sized neurons in lamina VII as well as a dense network of fibers in laminae IX and VII that contain calbindin D28k (calbindin)-like immunoreactivity. The highest frequency of immunoreactive (IR) cell bodies was found at the levels of the cervical and lumbar intumescences. Furthermore, rostrocaudally oriented calbindin-IR fibers were encountered in the ventral and ventrolateral funiculi throughout the whole length of the cord, with the highest density at cervical and lumbar intumescences. Analysis at the EM level revealed calbindin-IR terminals in contact preferentially with dendrites of variable size and occasionally also large cell bodies, presumably belonging to motoneurons, in the lateral motor nucleus. The location of calbindin-IR neurons, as well as the distribution and ultrastructural characteristics of the calbindin-IR axonal system, makes it highly likely that these neurons are Renshaw cells that mediate recurrent inhibition to motoneurons.

Animals↗

PubMed1992

A parsimonious description of motoneuron dendritic morphology using computer simulation.

Most quantitative descriptions of neuronal dendrite morphology involve tabulations of measurements and correlations among them. The present work is an attempt to extract from such data a parsimonious set of parameters that are sufficient to describe the quantitative features of individual and pooled dendrites, including their statistical variability. A relatively simple stochastic (Monte Carlo) model was devised to simulate branching dendritic trees. The necessary parameters were then derived directly from measurements of 64 completely reconstructed dendrites belonging to six gastrocnemius alpha-motoneurons, labeled by intracellular injection of HRP. Comparison of actual and simulated dendrites was used to guide the process of parameter extraction. The model included only two processes, one to generate individual branches given their starting diameters and the second to select starting diameters for the daughter branches produced at dichotomous branching points. The stochastic process for branch generation was controlled by probability functions for branching (Pbr) and for terminating (Ptrm), together with a constant rate of branch taper. All model parameters were fixed by motoneuron measurements except for branch taper rate, which was allowed to vary within limits consistent with observed taper rates in order to generate the appropriate total number of branches. The simplest model (model 1), in which Pbr and Ptrm depended only on local branch diameter, produced simulated dendrites that fit many, but not all, characteristics of actual motoneuron dendrites. Two additional properties produced significant improvements in the fit: (1) a small but significant dependence of daughter diameters on the normalized starting diameter of the parent branch, and (2) a dependence of Pbr and Ptrm on distance from the soma as well as on local branch diameter. The process of developing this model revealed unsuspected relations in the original data that suggest the existence of fundamental mechanisms for morphological control. The final model succinctly describes a large amount of data and will enable quantitative comparisons between the dendritic structures of different types of neurons, regardless of their relative sizes.

Animals↗

PubMed1991

Postnatal development of cat hind limb motoneurons supplying the intrinsic muscles of the foot sole.

The postnatal development of dendrite anatomy in alpha-motoneurons intracellularly labeled with horseradish peroxidase (HRP), innervating the intrinsic muscles of the sole of the foot (IFS MNs) in the cat, was investigated. The number of dendrites per neuron was about 11 and did not change from birth to adult. The number of branches per dendrite decreased during the same period by 20-25%. The net elimination of dendritic branches appeared to occur at distal branching points, as revealed by topological analysis. The dendritic branching pattern tended to be asymmetric at birth and the net decrease in dendritic branching postnatally did not alter this pattern. The length of preterminal branches (PTB) increased by a factor of 2, while terminal branch (TB) length increased by a factor of 3.3 postnatally. The large increase in TB length was attributed to both longitudinal growth and an apparent lengthening caused by resorption of distal branches during development. Dendritic length in the transverse spinal cord plane increased in parallel with the overall growth of the parent spinal cord segment, while dendritic growth along the rostro-caudal axis exceeded, by about one order of magnitude, dendritic growth in the transverse plane. Average branch diameter doubled from birth to adult. The decrease in branch diameter across branching points did not obey satisfactorily to the 'power rule' of Rall. However, the 1.5 power ratio of daughters-to-parents branch dropped from 1.18 to 1.08 between 3 weeks of age and adult. Tapering was evident in both PTBs and TBs. The rate of taper did not change postnatally. From birth onwards, 'local' branch diameter correlated closely with amount of membrane area and combined length of the dendritic branches located distal to the 'supporting' parent branch. These relations were similar in all age groups and are suggested to be properties intrinsic to the IFS MNs. The local branch diameter also co-varied with the number of distal dendritic branches, but in this case there was a systematic shift in the relationship with increasing postnatal age. It appears that the local diameter in IFS MN dendrites is a key indicator of the size of the distal dendritic arborization.

Animals↗

PubMed1991

Calcitonin gene-related peptide in monkey spinal cord and medulla oblongata.

The distribution of calcitonin gene-related peptide (CGRP)-immunoreactive (IR) fibers and cell bodies was studied in the spinal cord and the medulla oblongata of the grey monkey (Macaca fascicularis) using peroxidase-antiperoxidase (PAP) immunohistochemistry. At all levels of the spinal cord many CGRP-IR motoneurons and fibers were seen in the motor nuclei. In the medulla, CGRP-IR cell bodies were encountered in nucleus raphe obscurus, nucleus raphe pallidus and nucleus raphe magnus, nucleus reticularis lateralis as well as in the area dorsal to the inferior olive. Bulbar motoneurons were much more intensely stained than spinal cord motoneurons, indicating higher levels of CGRP-like immunoreactivity (LI) at the medullary level. The concentration of CGRP-LI measured by radioimmunoassay showed higher levels in the dorsal quadrants as compared to the ventral quadrants, but the dorsal/ventral ratio was lower than has previously been reported from the rat. The present results demonstrate that using the PAP technique CGRP-LI can be visualized in a larger number of spinal cord motoneurons of the monkey than earlier revealed by immunofluorescence. Moreover, the finding supports the view that the CGRP-IR nerve endings in the spinal motor nuclei originate from cell bodies in the medullary raphe nuclei.

Animals↗

PubMed1991

Distribution of 125I-galanin binding sites, immunoreactive galanin, and its coexistence with 5-hydroxytryptamine in the cat spinal cord: biochemical, histochemical, and experimental studies at the light and electron microscopic level.

The distribution of galanin-like immunoreactivity (GAL-LI) in the spinal cord of the cat was studied by use of indirect histochemistry and the peroxidase-antiperoxidase (PAP) technique. In the ventral horn GAL-immunoreactive (IR) axonal fibers and terminals were most frequent in the ventral part of the motor nucleus. The GAL-IR axons also contained 5-hydroxytryptamine (5-HT)-LI, and they disappeared after spinal cord transection. It was concluded that these GAL-IR fibers belong to the serotoninergic bublospinal pathway. In the medulla oblongata from normal cats, scattered GAL-IR cell bodies were encountered within the nucleus raphe obscurus and nucleus raphe pallidus. Electron microscopic observations revealed that the fine structure of the GAL-IR axonal boutons in the motor nucleus was similar to that of 5-HT-IR boutons with a varying number of immunoreactive large dense core vesicles. The postsynaptic element in all cases studied was a dendrite. A dense GAL-IR axonal plexus was found in the superficial laminae I-II of the dorsal horn. Coexistence was found between the GAL- and substance P-LI in fibers within the dorsal horn plexus. Spinal cord transection did not alter the pattern of GAL-LI in the dorsal horn, while the vast majority of GAL-IR axonal swellings disappeared following dorsal root sectioning. Electron microscopic observations in lamina II (substantia gelatinosa) revealed that the GAL-IR axonal terminals could be divided into two main groups. One with small to medium-sized axonal boutons formed synaptic contacts with both dendritic and axonal profiles. The other formed the central axon terminals of glomeruli, suggesting that GAL-LI may be present in C-type primary afferents. Numerous small GAL-IR cell bodies were encountered in laminae II and III. GAL-IR cell bodies were also observed in lamina X. The dorsal root ganglia contained a low but consistent number of small to medium-sized GAL-IR cell bodies, which all contained immunoreactive calcitonin gene-related peptide (CGRP). Following peripheral sciatic nerve transection, the number and the labeling intensity of GAL-IR cell bodies in the corresponding dorsal root ganglia showed a moderate increase. Radioimmunoassay revealed that the concentration of GAL-LI increased along the rostrocaudal axis of the normal spinal cord, and was about three times higher in the dorsal than in the ventral regions. The concentration in the dorsal root ganglia was intermediate to those seen in the corresponding dorsal and ventral cord regions.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

Imaging of fluorescent neurons labelled with fluoro-gold and fluorescent axon terminals labelled with AMCA (7-amino-4-methylcoumarine-3-acetic acid) conjugated antiserum using a UV-laser confocal scanning microscope.

This paper describes the implementation of an ultraviolet (UV) laser (Spectra Physics 171-18 with 3 lines: 334, 351 and 364 nm in UV) as light source for fluorescence confocal scanning microscopy. With this instrument it is possible to use fluorophores not previously available for confocal laser microscopical imaging of fluorophores such as fluoro-gold and AMCA. In the study we show confocal laser microscopical imaging of fluorescent motoneurons labelled by retrograde transport of fluoro-gold and AMCA-fluorescent axon terminals labelled with antisera against immunogenes as thyrotropin-releasing hormone (TRH) and calcitonin gene-related peptide (CGRP). These two fluorophores may be recorded simultaneously or separately by using a filter that suppresses the emission of one of the fluorophores. The described instrument should also be useful in applications involving detection of monoamines by the Falck-Hillarp technique, as well as measurements of cytosolic free calcium by indicators such as Fura-2 and Indo-1. Measurements performed in reflected and fluorescence light indicated that the resolution along the optical axis improved by about 25% when UV (351 nm) is used instead of visible light (514 nm). This figure is close to that expected on theoretical basis. There are, however, also serious problems related to the use of UV excitation. Firstly, objectives must be selected based on their UV transmission properties. Secondly, chromatic aberration may cause a substantial focal shift between illuminating and emitted light, calling for a flexible instrumental design in order to allow for compensation. As shown here, this problem can be circumvented by using reflecting objectives but at a price of lower resolution compared with high-aperture refracting objectives.

Animals↗

PubMed1990

Enkephalin-like immunoreactivity levels increase in the motor nucleus after an intramedullar axotomy of motoneurons in the adult cat spinal cord.

Neuropeptide- and serotonin-like immunoreactivities were studied in the lumbar spinal cord of the cat after a longitudinal incision in the ventral funiculus. This lesion, which accomplishes a central axotomy of motoneurons, was accompanied by increased level of Met-enkephalin-like immunoreactivity in nerve endings in those parts of the motor nucleus (lamina IX) which harbored severed motoneurons. This increase, which was evident in the fluorescence microscope, could be verified photometrically by use of a confocal scanning laser microscope.

Animals↗

PubMed1990

Evidence for coexistence between calcitonin gene-related peptide and serotonin in the bulbospinal pathway in the monkey.

By the use of the indirect immunofluorescence and in situ hybridization techniques, the distribution of calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) and CGRP mRNA was studied in the spinal cord as well as in the midline raphe nuclei and the hypoglossal nucleus in the medulla oblongata of the monkey (Macaca fascicularis). In the spinal cord only a few large neurons in the motor nucleus contained CGRP-LI, while a majority of the neurons in the hypoglossal nucleus contained CGRP-LI. A relatively dense innervation by CGRP-immunoreactive (IR) fibers was also seen close to cell bodies and proximal dendrites of large neurons in the motor nucleus, especially in its ventral part. 5-Hydroxytryptamine (5-HT)-, substance P- and thyrotropin-releasing hormone (TRH)-IR varicosities were also observed in a similar position around large neurons in the motor nucleus. Double labeling disclosed that the majority of CGRP-IR axon terminals also contained 5-HT-LI. Expression of CGRP mRNA was found in neurons in the medullary midline raphe nuclei and in large neurons in the motor nucleus at the cervical spinal cord level. In adjacent sections of the medulla oblongata, CGRP-labeled neurons in the midline raphe nuclei also expressed preprotachykinin mRNA. The present results show that CGRP- and 5-HT-LI coexist in fibers within the motor nucleus of the monkey spinal cord and that this coexistence is probably due to the presence of CGRP in the descending bulbospinal, serotonergic pathway.

Animals↗

PubMed1990

5-Hydroxytryptamine, substance P, and thyrotropin-releasing hormone in the adult cat spinal cord segment L7: immunohistochemical and chemical studies.

The terminal projections of the descending 5-hydroxytryptamine (5-HT) bulbospinal pathway and the coexistence among 5-HT-, substance P (SP)-, and thyrotropin-releasing hormone (TRH)-like immunoreactivities (LI) in fibers innervating the L7 segment in the cat spinal cord were studied quantitatively and semiquantitatively by use of the indirect double-staining immunofluorescence technique. The content of 5-HT, SP, and TRH in different parts of the spinal cord was determined by use of radioimmunoassay (RIA) (SP and TRH) and high-performance liquid chromatography with electrochemical detection (HPLC-ECD) (5-HT). For all three substances studied, immunoreactive (IR) axon terminals were found in all parts of the gray matter, but with clear regional variation in the density of innervation. Thus, all three substances showed a dense innervation in the motor nucleus, particularly in the ventral part of the nucleus, while the superficial dorsal horn was very densely innervated by SP-IR fibers (laminae I and II) and TRH-IR fibers (laminae II and III). In the motor nucleus, the studied substances coexisted to a very high degree, but some 5-HT-IR fibers (about 10%) lacked peptide-LI and some SP-IR fibers (about 10%) lacked 5-HT-LI while virtually all TRH-IR fibers also contained 5-HT-LI. In the superficial dorsal horn (laminae I-III), no coexistence was detected, while other parts of the gray matter displayed various degrees of coexistence in between those found in the motor nucleus and laminae I-III. The quantitative analysis of IR varicosities in the motor nucleus suggested that the unilateral L7 motor nucleus is innervated by about 55-110 x 10(6) 5-HT-IR nerve terminals, which may indicate as many as 4,000 boutons per descending 5-HT cell body in the brain stem only with this restricted projection. When combing these results with the biochemical data, it could be calculated that the concentration of 5-HT in IR varicosities is about 3-6 x 10(-3) M, while the corresponding figures for SP and TRH was 0.3-0.5 x 10(-3) M and 0.1-0.2 x 10(-3) M, respectively. In cats subjected to spinal cord transection at the lower thoracic level, all 5-HT-IR fibers in the L7 segment had disappeared 44 days after the lesion, indicating a strict suprasegmental origin of 5-HT-IR fibers in this segment.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1990

Anatomy of soleus alpha-motoneurone dendrites in normal cats and in cats subjected to chronic postnatal tenotomy or overload of the soleus muscle.

The anatomy of intracellularly HRP-labeled soleus alpha-motoneurone dendrites was studied both in normal adult cats ("normal soleus", NS) and in adult cats which at a postnatal age of 5-7 days had been subjected to chronic tenotomy of either the soleus muscle ("tenotomized soleus", TS), or all the soleus synergists contributing to the achilles tendon ("overloaded soleus", OS). A set of "structural rules" seemed to govern the architecture of normal soleus alpha-motoneurone dendrites. Thus, the dendrites branched dichotomously and the number of daughter branches originating from a preterminal branch was proportional to the diameter of that parent branch. Branch diameter decreased across branching points according to the "3/2 power rule" of Rall (1959). Branching occurred down to a preterminal branch diameter of about 0.8 micron. Through all branch orders there existed a quite precise relation between the diameter of a preterminal branch and the membrane area of its distal dendritic arborization. The average dendritic path distance from soma to termination was not closely related to the diameter of the stem dendrite, since thick stem dendrites rather generated more profusely branched arborizations than thin stem dendrites. As a corollary of these characteristics close relations existed between the dendritic stem diameter on one hand, and the total number of branches, combined dendritic length, total dendritic membrane area and total volume, on the other. In the OS material, the dendrites were not different from those of normal soleus motoneurone dendrites. In the TS material, the dendrites were less branched and had greater dendritic path lengths, although the relations between various size-parameters within the dendrites were not significantly altered compared with normal dendrites. It was concluded that the change in branching pattern was due to a net elimination of dendritic branches following the muscle tenotomy.

Achilles Tendon↗

PubMed1990

Peripheral nerve section induces increased levels of calcitonin gene-related peptide (CGRP)-like immunoreactivity in axotomized motoneurons.

By use of fluorescence immunohistochemistry it is shown that sciatic nerve section in cat and rat induces increased levels of immunoreactive calcitonin gene-related peptide (CGRP) in axotomized motoneurons. In the rat, this effect was clearly seen at 2-5 days postoperatively, but could not be demonstrated after 11-21 days. These findings are discussed in relation to previously proposed roles for CGRP in motoneurons.

Animals↗

PubMed1990

Changes in size and shape during histochemical preparation for light and electron microscopy of neurons intracellularly labelled with horseradish peroxidase.

In this study we show that neurons labelled intracellularly with horseradish peroxidase react differently from surrounding unlabelled neurons in vibratome sections during histological preparations for light and electron microscopy. The diameters and cross-sectional area of the cell bodies of intracellularly horseradish peroxidase-labelled neurons increased by about 6 and 11% respectively, while the surrounding unlabelled neurons decreased by the same amount. Also, the caliber of the proximal dendrites of horseradish peroxidase-labelled neurons increased during the histological preparation while dendritic path lengths remained unchanged. Since the surrounding tissue shrunk, the dendritic path shapes became more tortuous during histological processing. The demonstrated reaction of horseradish peroxidase-labelled neurons is suggested to be caused by the horseradish peroxidase reaction product.

Animals↗

PubMed1990

Computerized quantification of immunofluorescence-labeled axon terminals and analysis of co-localization of neurochemicals in axon terminals with a confocal scanning laser microscope.

The confocal scanning laser microscope (CSLM) offers improved optical resolution and contrast, high photometric precision, and the ability to make optical sections. These benefits were explored for use in quantitative analysis of immunofluorescence-labeled axon terminals. Guidelines were obtained for adjustments of the CSLM parameters. In the present applications, bleaching of the fluorescence did not represent a serious obstacle to analysis with the CSLM. A method was developed to distinguish the background fluorescence from the specific fluorescence labeling. This procedure made way for the development of automated quantification of immunolabeled axon terminals. The automated procedures substantially reduced the man-hour expenditure for analysis and provided highly reproducible quantifications compared with manual methods. The increased resolution and contrast of the CSLM allowed measurements of the fluorescence signal strength of individual axon terminals. The CSLM also allowed detection of co-localized neurochemicals in axon terminals.

Animals↗