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Gray commissure

About: Gray commissure is a research topic. Over the lifetime, 40 publications have been published within this topic receiving 3224 citations.

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Journal ArticleDOI
TL;DR: Cell number, size, and somatotopic arrangement within the spinal ganglia of the cells of origin of the rat dorsal penile nerve, and their spinal cord projections, were studied by loading the proximal stump of the severed DPN with horseradish peroxidase (HRP).
Abstract: Cell number, size, and somatotopic arrangement within the spinal ganglia of the cells of origin of the rat dorsal penile nerve (DPN), and their spinal cord projections, were studied by loading the proximal stump of the severed DPN with horseradish peroxidase (HRP). The DPN sensory cells were located entirely in the sixth lumbar (L6) dorsal root ganglia (DRG), in which a mean of 468 78 cells per side were observed, measuring 26.7 + 0.8 pm in their longest axis (range 10-65 pm) and distributed apparently randomly within the ganglia. Within the spinal cord, no retrograde label was found, i.e., no motoneurons were labeled, indicating that in the rat the DPN is formed exclusively of sensory nerve fibers. Although labeled fibers entered the cord only through L6, transganglionically transported HRP was evident in all spinal segments examined, i.e., TI3-S2. Labeled fibers projected along the inner edge of the dorsal horn (medial pathway) throughout their extensive craniosacral distribution. However, laminar distribution varied with spinal segment. In the dorsal horn, terminals or preterminal axons were found in the dorsal horn marginal zone (lamina I), the substantia gelatinosa (lamina 111, the nucleus proprius (laminae I11 and IV-the most consistent projection), Clarke's column (lamina VI), and the dorsal gray commissure. In the ventral horn, terminals were found in lamina VII and lamina IX. Label apposed to cell somas and dentrites in lamina VII may represent direct primary afferent projections onto sympathetic autonomic neurons. In lamina IX, labeled terminals delineated the somas and dendrites of cells that appeared to be motoneurons. This is the first description of an apparently monosynaptic contact onto motoneurons by a primary afferent of nonmuscle origin.

104 citations

Journal ArticleDOI
TL;DR: Splanchnic afferent projections to the spinal cord and gracile nucleus were labeled following the application of HRP to the central cut end of the major splanchnic nerve.
Abstract: Splanchnic afferent projections to the spinal cord and gracile nucleus were labeled following the application of HRP to the central cut end of the major splanchnic nerve. Labeled afferent fibers were detected in the ipsilateral dorsal column, in Lissauer's tract (LT), in laminae 1, 5, 7, and 10, and in the dorsal gray commissure at T1-T13 levels of the spinal cord. Afferent projections were not identified in laminae 2-4. Collaterals from LT projected ventrally along the lateral and medial margins of the dorsal horn (called lateral and medial pathways, respectively). Afferents in the lateral pathway formed small bundles, spaced rostrocaudally at intervals of 300-1,000 microns, which passed medially at the base of the dorsal horn into laminae 5, 7, and 10 and to the contralateral spinal cord. Some afferents in the lateral pathway projected to the intermediolateral nucleus where labeled sympathetic preganglionic neurons were located. Afferents in the medial pathway entered the lateral aspect of the dorsal column and projected as a group near the midline rostrally to the medulla. The dorsal column pathway terminated in the ventral gracile nucleus in four or five clusters, each occupying a region ranging in size from 0.01-0.1 mm3 and separated in the rostrocaudal axis by distances of 400-800 microns. These clusters were concentrated in the middle and caudal portions of the nucleus below the obex. A comparison of the present results with those from earlier experiments on the central projections of afferent fibers from the heart, kidney, and pelvic organs demonstrates a consistent pattern of visceral afferent termination in the thoracolumbar and sacral segments of the spinal cord. This is not unexpected, since visceral afferent pathways to different organs perform similar functions, such as the transmission of nociceptive information and the initiation of autonomic reflexes.

97 citations

Journal ArticleDOI
TL;DR: An analysis of vasoactive intestinal polypeptide immunoreactivity (VIP‐IR) and substance P‐IR in the cat spinal cord has revealed marked differences in the distribution of the two peptides.
Abstract: An analysis of vasoactive intestinal polypeptide immunoreactivity (VIP-IR) and substance P-IR in the cat spinal cord has revealed marked differences in the distribution of the two peptides. While substance P-IR was located at all levels of the cord, VIP-IR was most prominent in the sacral segments in Lissauer's tract and lamina I on the lateral edge of the dorsal horn. VIP-IR was also present in the sacral cord in (1) laminae V, VII, and X, (2) a thin band on the medial side of the dorsal horn, (3) the dorsal commissure, (4) the lateral band of the sacral parasympathetic ucleus, and (5) in a few animals in Onuf's nucleus. In other segments of the spinal cord VIP-IR was much less prominent but was present in Lissauer's tract and laminae I, II, and X. Substance P-IR was more uniformly distributed at all segmental levels in laminae I–III, V, VII, and X and in the dorsal commissure. In ventrolateral lamina I of the sacral spinal cord both VIP-IR and substance P-IR exhibited a distinctive periodic pattern in te rostrocaudal axis. The peptides were associated with bundles of dorsoventrally oriented axons and varicosities spaced at approximately 210-μm intervals center to center along the length of the spinal cord. The bundles in lamina I continued into lamina V where they further divided into smaller bundles that extended medially through laminae V and VII. The most prominent bundles of VIP axons passed ventrally from lateral laminae V and VII to enter lamina X and the ventral part of te dorsal gray commissure. On the other hand the maority of substance P axons in lamina V turned dorsally to join wth axons on the medial side of the dorsal horn and to pass into the dorsal part of the dorsal gray commissure. Rostrocaudal VIP axons were present not only in Lissauer's tract but also in dorsolateral lamina I, in the lateral funiculus and in the ependymal cell layer of the central canal. Following unilateral transectionofthe sacral dorsal roots (2 weeks–22 months) the density of VIP axons and terminals was markedly reduced in ipsilateral Lissauer's trat and lateral laminae I and V; however, no change was detected in lamina X. Sacral deafferentation reduced substance P-IR in the dorsal gray commissure and in lateral laminae I and V. It is concluded that VIP-IR and substance P-IR are present at all levels of the cat spinal cord, but that VIP-IR is most prominent in sacral afferent pathways. The distribution of VIP-IR in spinal cord was very similar to the central projections of sacral visceral afferents. These findings are consistent with data from other experiments indicating that VIP may be a transmitter in visceral afferent pathways.

94 citations

Journal ArticleDOI
TL;DR: The results indicate that all parasympathetic preganglionic neurons and their related interneurons which contribute to the innervation of cavernosal tissue bear 5-hydroxytryptamine2C receptors.

93 citations

Journal ArticleDOI
TL;DR: NFF is an FMRF‐NH2‐like peptide with morphine‐modulating effects that is highly concentrated in spinal cords of various mammalian species and there is evidence that NFF participates in the modulation of nociceptive mechanisms.
Abstract: Neuropeptide FF, or F8Famide (Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2; “morphine-modulating peptide”), isolated from bovine brain, is an FMRF-NH2-like peptide with morphine-modulating effects. Neuropeptide FF (NFF) is highly concentrated in spinal cords of various mammalian species. There is evidence that NFF participates in the modulation of nociceptive mechanisms. The present study was aimed at describing the distribution and origin of the neuropeptide-FF-like immunoreactivity (LI) in the rat spinal cord. For distribution studies spinal cord sections from colchicine-treated animals were processed according to the indirect immunofluorescence method. Retrograde fluorescent tracer was injected in the lumbar dorsal spinal cord to study descending NFF-LI-containing spinal pathways. NFF-immunoreactive (ir) cell bodies were detected in the substantia gelatinosa, marginal zone, laminae III, IV, and X at all levels of the spinal cord, and the dorsolateral funiculus, and dorsal gray commissure of the lumbosacral transition zone. NFF-ir fibers and terminals were identified in laminae I-IV and X, dorsolateral funiculus, intermediolateral cell column, dorsal gray commissure, sacral parasympathetic nucleus, and ventral horn. A spinal NFF-LI-containing descending pathway originating in the lamina X neurons was observed, but a supraspinal origin of descending NFF-ir fibers was not identified. According to this study the NFF-LI of the spinal cord is of intrinsic spinal origin. The anatomical distribution supports the concept that the NFF-like peptides have a role in the nociception. They may also be involved in sensory-visceral reflex arcs.

73 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20211
20201
20191
20181
20141
20081