The central termination of sensory fibers from nerves to the gastrocnemius muscle of the rat

Panneton, W. Michael; Gan, Qi; Juric, Rajko

doi:10.1016/j.neuroscience.2005.02.032

Cited by 38 publications

(40 citation statements)

References 71 publications

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“…Macroscopic images of multiple segmental levels of the spinal cord stained for cSNAP-25 are shown in Figures 4A,B. In accordance with the fact that the L5 nerve dominantly innervates the gastrocnemius muscle (23), strong immunoreactivity for cSNAP-25 was observed in the ventral and dorsal horns of the spinal cord at the segmental level of L5 ipsilateral to the peripheral toxin injection site, but also to a lesser extent on the contralateral side. Microscopic observations at higher magnification showed the characteristic localization patterns of cSNAP-25 immunolabeling in the anterior horn (lamina IX) of the spinal cord at L5, where cSNAP-25-immunoreactive products appeared as tiny dots that formed fibrous configurations and were numerously found on the ipsilateral side (Figures 4C,E), but less numerously on the contralateral side (Figures 4D,F).…”

Section: Resultssupporting

confidence: 53%

Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2

et al. 2014

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Because of its unique ability to exert long-lasting synaptic transmission blockade, botulinum neurotoxin A (BoNT/A) is used to treat a wide variety of disorders involving peripheral nerve terminal hyperexcitability. However, it has been a matter of debate whether this toxin has central or peripheral sites of action. We employed a rat model in which BoNT/A1 or BoNT/A2 was unilaterally injected into the gastrocnemius muscle. On time-course measurements of compound muscle action potential (CMAP) amplitudes after injection of BoNT/A1 or BoNT/A2 at doses ranging from 1.7 to 13.6 U, CMAP amplitude for the ipsilateral hind leg was markedly decreased on the first day, and this muscle flaccidity persisted up to the 14th day. Of note, both BoNT/A1 and BoNT/A2 administrations also resulted in decreased CMAP amplitudes for the contralateral leg in a dose-dependent manner ranging from 1.7 to 13.6 U, and this muscle flaccidity increased until the fourth day and then slowly recovered. Immunohistochemical results revealed that BoNT/A-cleaved synaptosomal-associated protein of 25 kDa (SNAP-25) appeared in the bilateral ventral and dorsal horns 4 days after injection of BoNT/A1 (10 U) or BoNT/A2 (10 U), although there seemed to be a wider spread of BoNT/A-cleaved SNAP-25 associated with BoNT/A1 than BoNT/A2 in the contralateral spinal cord. This suggests that the catalytically active BoNT/A1 and BoNT/A2 were axonally transported via peripheral motor and sensory nerves to the spinal cord, where they spread through a transcytosis (cell-to-cell trafficking) mechanism. Our results provide evidence for the central effects of intramuscularly administered BoNT/A1 and BoNT/A2 in the spinal cord, and a new insight into the clinical effects of peripheral BoNT/A applications.

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Section: Resultssupporting

confidence: 53%

Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2

et al. 2014

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“…Therefore, in former studies tissue-dependent differences in spinal LTP induction could not be determined. The GS and SU were selected, because the vast majority of their primary afferents terminate in approximately the same lumbar spinal segments L 3 -L 5 , mainly in segment L 4 (Hoheisel et al 1994;Panneton et al 2005). Therefore, SFPs elicited by C fibers from both nerves could be recorded in the same segment.…”

Section: Discussionmentioning

confidence: 99%

“…In the rat, spinal terminations of muscle C fibers cover larger areas than those of cutaneous C fibers and terminate predominantly in the deep spinal dorsal horn (lamina V), whereas nociceptors from the skin have a denser projection in the superficial dorsal horn (Ling et al 2003;Molander and Grant 1987;Panneton et al 2005).…”

Section: Discussionmentioning

confidence: 99%

High-frequency modulation of rat spinal field potentials: effects of slowly conducting muscle vs. skin afferents

Zhang

Hoheisel

Klein

et al. 2016

Journal of Neurophysiology

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Zhang J, Hoheisel U, Klein T, Magerl W, Mense S, Treede RD. High-frequency modulation of rat spinal field potentials: effects of slowly conducting muscle vs. skin afferents. J Neurophysiol 115: 692-700, 2016. First published November 11, 2015 doi:10.1152/jn.00415.2015 in rat spinal dorsal horn neurons was induced by electrical high-frequency stimulation (HFS) of afferent C fibers. LTP is generally assumed to be a key mechanism of spinal sensitization. To determine the contribution of skin and muscle afferents to LTP induction, the sural nerve (SU, pure skin nerve) or the gastrocnemiussoleus nerve (GS, pure muscle nerve) were stimulated individually. As a measure of spinal LTP, C-fiber-induced synaptic field potentials (SFPs) evoked by the GS and by the SU were recorded in the dorsal horn. HFS induced a sustained increase of SFPs of the same nerve for at least 3 h, indicating the elicitation of homosynaptic nociceptive spinal LTP. LTP after muscle nerve stimulation (HFS to GS) was more pronounced (increase to 248%, P Ͻ 0.05) compared with LTP after skin nerve stimulation (HFS applied to SU; increase to 151% of baseline, P Ͻ 0.05). HFS applied to GS also increased the SFPs of the unconditioned SU (heterosynaptic LTP) significantly, whereas HFS applied to SU had no significant impact on the SFP evoked by the GS. Collectively, the data indicate that HFS of a muscle or skin nerve evoked nociceptive spinal LTP with large effect sizes for homosynaptic LTP (Cohen's d of 0.8 -1.9) and small to medium effect sizes for heterosynaptic LTP (Cohen's d of 0.4 -0.65). The finding that homosynaptic and heterosynaptic LTP after HFS of the muscle nerve were more pronounced than those after HFS of a skin nerve suggests that muscle pain may be associated with more extensive LTP than cutaneous pain.

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“…For example, CGRP reactive fibers persisted in laminae I and V near the spinomedullary border. These fibers probably arose from rostral cervical dermatomes that overlap in the MDH (Stover et al, 1992; Sugimoto et al, 1997); Panneton et al previously have noted primary afferent fibers to these laminae provide only a blurred somatotopy at best (Panneton and Burton, 1981; Panneton, 1991; Panneton et al, 2005a, 2006, 2010c) since numerous peripheral targets provide projections to similar areas of neuropil. Primary afferent fibers in the glossopharyngeal and vagus nerves also invade superficial neuropil of the rostral MDH (Panneton, 1991), including the paratrigeminal nucleus, as well as laminae I and V. Such overlap substantiates that seen in the caudal MDH and spinal dorsal horn, again blurring somatotopy within these laminae.…”

Section: Peptides In the Trigeminal Sensory Complexmentioning

confidence: 99%

Direct reticular projections of trigeminal sensory fibers immunoreactive to CGRP: potential monosynaptic somatoautonomic projections

Panneton

Gan

2014

Front. Neurosci.

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Few trigeminal sensory fibers project centrally beyond the trigeminal sensory complex, with only projections of fibers carried in its sensory anterior ethmoidal (AEN) and intraoral nerves described. Fibers of the AEN project into the brainstem reticular formation where immunoreactivity against substance P and CGRP are found. We investigated whether the source of these peptides could be from trigeminal ganglion neurons by performing unilateral rhizotomies of the trigeminal root and looking for absence of label. After an 8–14 days survival, substance P immunoreactivity in the trigeminal sensory complex was diminished, but we could not conclude that the sole source of this peptide in the lateral parabrachial area and lateral reticular formation arises from primary afferent fibers. Immunoreactivity to CGRP after rhizotomy however was greatly diminished in the trigeminal sensory complex, confirming the observations of others. Moreover, CGRP immunoreactivity was nearly eliminated in fibers in the lateral parabrachial area, the caudal ventrolateral medulla, both the peri-ambiguus and ventral parts of the rostral ventrolateral medulla, in the external formation of the nucleus ambiguus, and diminished in the caudal pressor area. The nearly complete elimination of CGRP in the lateral reticular formation after rhizotomy suggests this peptide is carried in primary afferent fibers. Moreover, the arborization of CGRP immunoreactive fibers in these areas mimics that of direct projections from the AEN. Since electrical stimulation of the AEN induces cardiorespiratory adjustments including an apnea, peripheral vasoconstriction, and bradycardia similar to those seen in the mammalian diving response, we suggest these perturbations of autonomic behavior are enhanced by direct somatic primary afferent projections to these reticular neurons. We believe this to be first description of potential direct somatoautonomic projections to brainstem neurons regulating autonomic activity.

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The central termination of sensory fibers from nerves to the gastrocnemius muscle of the rat

Cited by 38 publications

References 71 publications

Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2

Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2

High-frequency modulation of rat spinal field potentials: effects of slowly conducting muscle vs. skin afferents

Direct reticular projections of trigeminal sensory fibers immunoreactive to CGRP: potential monosynaptic somatoautonomic projections

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