The organization of neuronal somata in the first sacral spinal ganglion of the cat (original) (raw)
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Lamellar Arrangement of Neuronal Somata in the Dorsal Root Ganglion of the Cat
Somatosensory & Motor Research, 1985
The retrograde transport of horseradish peroxidase (H RP) was used to study the distribution of perikarya in the dorsal root ganglia (DRGs). lnjections of HRP subcutaneously into a small area of the foreleg, flank, perineum, the central pad of the forepaw, muscles of the foreleg, the wall of the urinary bladder, and mucosa of the rectum resulted in many retrogradely labeled perikarya in one DRG. Labeled perikarya were distributed in the ganglia proximally to distal elongated slabs or columns, especially in cases of subcutaneous injections. A similar slab, or columnar distribution, of HRP-labeled perikarya was noticed when the tracer was injected into the spinal cord preceded by the transection of all dorsal root filaments but one. Perikarya located along the lateral border of the ganglion were labeled through rostra1 filaments, and perikarya distributed along the medial border were labeled through caudal filaments. A segmental somatotopic map has been conceived for the DRG as an intermediate territory between the periphery and the spinal cord.
Experimental Eye Research, 2000
Transganglionic transport of wheatgerm agglutinin conjugated horseradish peroxidase WGA-HRP) was used to reveal the central distribution of terminals of primary afferent fibers from peripheral nerves innervating the hind leg of the rat. In separate experiments the sizes and locations of cutaneous peripheral receptive fields were determined by electrophysiological recording techniques for each of the nerves that had been labeled with WGA-HRP. By using digital image analysis, the sizes and positions of the peripheral receptive fields were correlated with the areas of superficial dorsal horn occupied by terminals of primary afferents from each of these receptive fields. Data were obtained from the posterior cutaneous nerve of the thigh, lateral sural, sural, saphenous, superficial peroneal, and tibial nerves. The subdivisions of the sciatic nerve, the sural, lateral sural, superficial peroneal, and tibial nerves each projected to a separate and distinct region of the superficial dorsal horn and collectively formed a "U"-shaped zone of terminal labeling extending from lumbar spinal segments L2 to the caudal portions of L5. The gap in the "U" extended from L2 to the L3-4 boundary and was occupied by terminals from the saphenous nerve. Collectively, all primary afferents supplying the hindlimb occupied the medial 3/4 of the superficial dorsal horn with terminals from the tibial nerve lying most medially and occupying the largest of all the terminal fields. Afferents from the superficial peroneal lay in a zone between the medially situated tibial zone and the more laterally placed sural zone. Afferents from the posterior cutaneous nerve were located most caudally and laterally. Terminal fields from the posterior cutaneous and saphenous nerves differed from the others in having split representations caused presumably by their proximity to the mid-axial line of the limb. Comparisons between the peripheral and the central representations of each nerve revealed that 1 mm2 of surface area of the superficial dorsal horn serves approximately 600-900 mm2 of hairy skin and roughly 300 mm2 of glabrous skin. The vast majority of terminal labeling observed in the dorsal horn was found in the marginal layer and substantia gelatinosa, suggesting that small diameter afferents have a n orderly somatotopic arrangement in which each portion of the skin surface is innervated by afferent fibers that terminate in preferred localities within the dorsal horn.
Neuronal organization and cell interactions of the cat stellate ganglion
Autonomic Neuroscience, 2002
The functional structure of the cat stellate ganglion (SG) and, in particular, its extra-and intraganglionic connections and neuronal organization, were investigated using histochemical, immunohistochemical, morphological and histological methods. Retrograde axonal transport of horseradish peroxidase was used to determine most of the extraganglionic interactions. Of the targets tested, the most extensive efferent connections of the SG were with the sternocleidomastoid muscle, trachea, esophagus and heart. Neurons of the SG also send a small number of postganglionic efferents to the thyroid and stomach. Furthermore, ganglion cells send axons to the spinal ganglia. Several afferent connections of the SG were determined. Sympathetic preganglionic neurons of segments C8 -T10 of the spinal cord, sensory neurons of C8 -T9 spinal ganglia, intramural ganglia of the thoracic viscera and the reticular formation of the medulla oblongata send their axons to the SG. Intraganglionic interactions of interneurons with principal ganglionic cells were assumed to occur, based on the presence of interneurons immunoreactive to GABA and substance P. GABA-and substance P-immunoreactive fibers located around a small number of postganglionic neurons were also identified. Morphological study revealed asymmetry between the left and right ganglia: the right ganglion is larger than the left and contains more cells. This asymmetry was also reflected in basic structural parameters of neurons, such as average neuronal area and average diameter of cell somata. The present data has been used to develop a scheme for the basic inter-and intraneuronal connections of the cat SG. This ganglion is a true nervous center, with postganglionic neurons, some of which might be performing sensory functions, and interneurons. The ganglion is connected not only with the spinal cord and spinal ganglia, but also with neurons of the intramural ganglia and, by direct links, with efferent neurons of the medulla oblongata. Thus, the SG may play an essential role in viscera-visceral reflexes. D Efferent and afferent connections 1566-0702/02/$ -see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 1 5 6 6 -0 7 0 2 ( 0 1 ) 0 0 3 6 0 -5
Neuroscience Letters, 1998
The topographical distribution of sciatic and femoral nerve sensory neuronal somata in the L4 dorsal root ganglion of the adult rat was mapped after retrograde tracing with one or two of the dyes Fast Blue, Fluoro-Gold, or Diamidino Yellow. The tracers were applied to the proximal transected end of either nerve alone, or from both nerves in the same animal using separate tracers. Three-dimensional reconstructions of the distribution of labelled neurones were made from serial sections of the L4 dorsal root ganglion which is the only ganglion that these two nerves share. The results showed that with little overlap, femoral nerve neurones distribute dorsally and rostrally whereas sciatic nerve neurones distribute medially and ventrally. This finding indicates the existence of a somatotopical organisation for the representation of different peripheral nerves in dorsal root ganglia of adult animals.
Anatomy and Embryology, 1994
The dorsal root ganglia (DRGs) of the rat have a rostrocaudal organization. This organization can most easily be demonstrated in fetal and neonatal rats because the spatial relationships of their DRGs are maintained better in tissue sections than those of mature rats. This review is concerned with the way in which the rostrocaudal organization of the DRGs is generated. Wheat germ agglutinin -horseradish peroxidase/horseradish peroxidase labeling of peripheral nerves of the brachial and lumbar plexuses shows that the position of the somata of the sensory neurons of the labeled nerves can be restricted to rostral or caudal halves of DRGs. Labeling of the thoracic nerve or its branches always results in labeling throughout the entire thoracic DRG. After application of the marker to forelimb nerves, it was observed that whenever a DRG is labeled only partially, its spinal nerve is correspondingly labeled partially as well. These data suggest that the rostrocaudal organization in the DRG is related to the formation of the plexuses. During development nerve fibers can be segmentally labeled, using the subdivision of the DRGs into a rostral and a caudal half to keep together as they find their way through the plexus. Application of label to forelimb skin, hindlimb skin and even thoracic skin can result in labeling of rostral or caudal halves of a DRG. A possible explanation might be that each dermatome can be divided into a skin area innervated by the rostral half of a DRG and a skin area innervated by the caudal half of the same dorsal root ganglion. In the rat, the segmental sensory innervation of muscles during development has not yet been investigated. The question of whether the segmental unit of innervation of a muscle is a whole DRG or half a DRG therefore still remains unanswered.
Brain Research Bulletin, 1989
of spinal cord preganglionic neurons innervating the superior cervical ganglion in the golden hamster. BRAIN RES BULL 22(2) 289-293, 1989.-The retrograde neuronal tracer Fluoro-Gold (FG) was used to determine the location and distribution of preganglionic sympathetic neurons in the spinal cord of the golden hamster. FG was injected unilaterally into the superior cervical ganglia. Labeled neurons were found only ipsilateral to the injection site in segments C8 to TS of which the segments Tl to T3 contained about 98% of the labeled cells. Neurons were found in four regions of the spinal cord: the intermediolateral nucleus (43%), the lateral funiculus (S%), the central autonomic area (1%) and the intercalated region (less than 1%). In the intermediolateral nucleus, cells often were arranged in clusters of which several were seen in each spinal segment. Fluoro-Gold Golden hamster Superior cervical ganglion Spinal cord Sympathetic neurons
Brain Research, 1989
The projections of coarse and fine axons of the glossopharyngeal (IX) nerve upon the caudal two thirds of the nucleus of the tractus solitarius (NTS) were studied in the cat. These afferents convey the chemo-and baroreceptor activities from the carotid receptors. We applied the Fink-Heimer method on brainstem sections, at different survival times, after a petrosal ganglionectomy. A segregation of fine and coarse fibered components was observed. Degeneration of coarse axons was mostly found in the lateral NTS, while fine fiber degeneration was predominant in regions of the medial and commissural NTS. The injection of WGA-HRP in the different NTS divisions demonstrated that the lateral NTS was mainly innervated by the set of largest neurons of the petrosal ganglion and that the medial and the commissural NTS were innervated by the set of smaller neurons of the ganglia. These results were discussed in relation to cytoarchitecture, myeloarchitecture, distribution of normal axons, and known central connectivity of the different NTS divisions. We concluded that coarse and fine visceral afferents of the IX nerve, which includes the afferents of the carotid body and the carotid sinus, represent different afferent populations that project to particular divisions of the NTS and connect to different central pathways.
The Journal of Comparative Neurology, 1991
The spinal accessory nerve has been generally thought to be a cranial nerve with purely motor function, innervating the trapezius and sternocleidomastoid muscles. The present study identified clusters of sensory neurons consistently associated with this cranial nerve in adult rats. Either a single microganglion or several dispersed microganglia were found that adhered to the spinal root of the nerve, to small vessels, or were free within the subarachnoid space. The neurons of the ganglion had axons that joined the spinal root of the nerve proximal to its exit from the skull. Additional branches appeared to have an intracranial distribution within the arachnoid of the brainstem and along its vessels. Several findings suggest that the function of the ganglion is sensory and not autonomic. First, the architectural features of neurons within the ganglion (including their size, pseudounipolar morphology, and the lack of synaptic contacts) are similar to those of neurons in other sensory ganglia. Second, substance P and calcitonin gene-related peptide coexist within neurons of the microganglion, whereas markers for the major transmitters found in autonomic ganglia in rats are absent. Third, the expression of peptides in neurons of the ganglion was sensitive to neonatal capsaicin treatment. Finally, neurons within the ganglion were filled with a retrogradely transported dye after injection of the dye into the cervical spinal cord. Although the function of the ganglion is not known, its features are consistent with a role in nociception from the muscles of the spinal accessory complex, and it may be involved in headaches that have an occipital distribution.
The Journal of Physiology, 1977
The ability ofpreganglionic axons to re-establish their normal pattern of synaptic connexions with superior cervical ganglion cells has been studied after section of the cervical sympathetic trunk. 2. In vivo stimulation ofthe last cervical (C8) and the first seven thoracic ventral roots (T1-T7) 3-4 months after section of the trunk produced endorgan responses similar to those observed in normal animals. 3. The pattern of innervation of individual neurones, determined by intracellular recording of synaptic potentials 4-9 months after cutting the sympathetic trunk, was also similar to that observed in normal neurones. Both normal and re-innervated ganglion cells were contacted by pre
Journal of Comparative Neurology
The organization of neurons in the lumbar enlargement of the rat spinal cord processing information conveyed by group II afferents of hind-limb muscle nerves has been investigated by using cord dorsum and intraspinal field potential recording. Group II afferents of different muscle nerves were found to evoke their strongest synaptic actions in specific segments of the lumbar cord. Group II afferents of quadriceps and deep peroneal nerves evoked potentials mainly at the rostral end of the lumbar enlargement (L1-rostral L3), whereas group II afferents of gastrocnemius-soleus and hamstring nerves evoked their main synaptic actions at the caudal end of the lumbar enlargement (L5). In the central lumbar segments (caudal L3-L4), the largest group II potentials were produced by afferents of tibialis posterior and, to a lesser degree, flexor digitorum longus. Field potentials evoked by group II afferents of quadriceps, tibialis posterior, and flexor digitorum longus were largest in the dorsal horn (up to 600 µV), but also occurred in the ventral horn where they were sometimes preceded by group I field potentials. In contrast, field potentials evoked by group II afferents of gastrocnemius-soleus and hamstring nerves were restricted to the dorsal horn. These results indicate that neurons in different segments of the rat lumbar spinal cord process information from group II afferents of different hind-limb muscles. Furthermore, the topographical organization of group II neuronal systems in the rat is similar in several respects to that in the cat and may therefore represent a general organizational feature of the mammalian spinal cord.