Effects of sciatic nerve crush on the L7 spinal roots and dorsal root ganglia in kittens

The number and size distribution of axons and neurons were examined in the L7 spinal roots and ganglia of kittens 14 to 220 days after early postnatal sciatic nerve crush. The results show that motoraxons in the ventral root as well as axons and perikarya of sensory neurons in the dorsal root remained growth-retarded throughout the examined period. This was most evident in the dorsal root. Both ventral and dorsal roots showed some loss of myelinated axons, but this was only half that previously observed after sciatic nerve resection. Whereas in the dorsal roots and dorsal root ganglia the loss seemed to be nonselective with respect to size, axons in the gamma range were primarily affected in the ventral roots. In the dorsal roots the proportion of unmyelinated axons was comparable with controls but in the ventral roots it was somewhat elevated. In most cases the loss of dorsal root ganglion neurons was relatively greater than the decrease of dorsal root axons.     

Structural changes in kittens' ventral and dorsal roots L7 after early postnatal sciatic nerve transection

The number and size distribution of myelinated and unmyelinated axons were studied in spinal roots L7 of 19 kittens, 8 to 200 days after early postnatal left sciatic nerve transection. Ventral and dorsal roots on the side of transection were compared with corresponding contralateral roots. Three normal kittens were used as additional controls. On the control side the proportion of unmyelinated ventral root axons increased from about 15 to 30% between 3 and 7 months postnatally. In the ventral roots on the lesion side there was a loss of myelinated axons of all sizes (total loss 15 to 25%). The loss seemed to be somewhat greater in the gamma population. The number of unmyelinated ventral root axons increased markedly through sprouting. This increase was similar at different root levels. The persistence of such axonal sprouts in the proximal stump after ventral root division in one kitten indicated that they originate proximally in the ventral root or within the central nervous system. The dorsal roots on the lesion side showed a 30% deficit of both myelinated and unmyelinated axons. Signs of axonal sprouting were not observed. Both in ventral and dorsal roots the size spectra of myelinated axons were markedly shifted to the left on the lesion side due to a growth retardation of larger axons. With respect to the unmyelinated axons the size distribution was expanded toward larger sizes in the ventral roots and remained largely unaltered in the dorsal roots.     

Catecholamine varicosities in cat dorsal root ganglion and spinal ventral roots

Convergence upon reticulospinal neurons which mediate disynaptic, contralateral pyramidal EPSPs to neck motoneurons has been examined in cats with contralateral pyramidal transection at the obex. Conditioning stimuli in the contralateral tectum and ipsilateral mesencephalic tegmentum produced monosynaptic facilitation of the disynaptic pyramidal EPSP, whereas facilitation evoked from the ipsilateral pyramid showed a disynaptic time course. These results show that contralateral pyramidal, tectal and ipsilateral tegmental fibers converge onto common reticulospinal neurons which have direct excitatory connections with neck motoneurons.     

Evidence for spinal origin of neurons synapsing with dorsal root ganglion cells of the cat

The visuotopic structure of primary visual cortex was studied in a group of 7 human volunteers using positron emission transaxial tomography (PETT) and 18F-labeled 2-deoxy-2-fluoro-D-glucose ( [18F]DG). A computer animation was constructed with a spatial structure which was matched to estimates of human cortical magnification factor and to striate cortex stimulus preferences. A lateralized cortical 'checker-board' pattern of [18F]DG was stimulated in primary visual cortex by having subjects view this computer animation following i.v. injection of [18F]DG. The spatial structure of the stimulus was designed to produce an easily recognizable 'signature' in a series of 9 serial PETT scans obtained from each of a group of 7 volunteers. The predicted lateralized topographic 'signature' was observed in 6 of 7 subjects. Applications of this method for further PETT studies of human visual cortex are discussed.     

单侧坐骨神经完全结扎术后Ⅰ型囊泡膜谷氨酸转运体在大鼠腰髓、背根神经节和结扎远侧端神经干内表达的变化

目的　 研究单侧坐骨神经结扎对大鼠腰 4～ 5脊髓节段和相应的背根神经节 (DRGs)内VGluT1样免疫阳性反应产物表达的影响以及VGluT1通过轴浆流向外周转运的情况。 方法　 采用免疫组织化学方法观察单侧坐骨神经结扎后不同时间内腰 4～ 5脊髓节段、DRGs和结扎部位的近、远侧端神经干内VGLuT1样免疫阳性反应强度的变化。结果　 (1)坐骨神经结扎后第 1和第 2天 ,VGluT1样免疫阳性产物在结扎的同侧腰 4～ 5脊髓节段和相应节段的DRGs内未检测到明显变化 ;但自术后第 4天开始 ,可观察到VGluT1样免疫阳性产物的表达在上述部位逐渐减弱 ;VGluT1样免疫阳性产物表达的降低在上述部位所出现的时间和程度相平行。 (2 )结扎后第 1天即可观察到VGluT1样免疫阳性产物在坐骨神经结扎部位近侧端的表达有所升高 ,但自术后第 4天开始逐渐降低 ;而VGluT1样免疫阳性产物在坐骨神经结扎部位远侧端的表达自结扎后第 1天起就逐渐降低 ,至第 4周时已完全消失。结论　 (1)DRG神经元合成VGluT1,并通过轴浆流将VGLluT1向中枢突和周围突运输 ,故腰髓内部分VGluT1样阳性末梢起源于DRG神经元 ;(2 )外周神经的损伤很易影响到DRG神经元内VGluT1的合成     

Selective degeneration of dorsal root ganglia and dorsal nerve roots in methyl mercury-intoxicated rats: a stereological study

The components of the nervous system of rats that are most critically affected by methyl mercury are still a matter of debate. A recent stereological study of rats with typical symptoms resulting from methyl mercury intoxication demonstrated that the morphology of cerebellar granule cells and Purkinje cells were unchanged at the light microscopic level, even though there was pronounced degeneration of myelinated axons in dorsal nerve root nerves. In the present study, unbiased stereological methods were used to quantify morphological changes in the dorsal root ganglion, and dorsal and ventral nerve roots of the rats used in the previous study. The rats were treated with methyl mercury (2 mg daily/kg, per os) for a 19-day period that was followed by a 32-day period without treatment. The means of the total numbers of A-cell and B-cell perikarya in the dorsal root ganglion of the intoxicated rats were reduced by 60% and 24%, respectively. The mean volume of A-cell perikarya in rats of the experimental group was reduced by 22%, whereas the mean volume of B-cell perikarya was the same in the two groups. In the experimental group, the total number of myelinated axons in the dorsal nerve roots was reduced by 60%, whereas no difference was found in the ventral nerve roots. The areas of axon and myelin sheath, dorsal and ventral nerve roots were not affected. This study demonstrates that extensive loss of dorsal root ganglion cells and myelinated axons in dorsal nerve roots precedes light microscopical changes in the ventral nerve roots and the cerebellum of rats intoxicated with methyl mercury. Received: 16 January 1998 / Revised, accepted: 23 February 1998     

A temporal variation in nonneuronal protein synthesis in dorsal root ganglia and nerve and its significance to studies of axonal transport

Protein synthesis and fast axonal transport were studied in vitro using dorsal root ganglia (DRG)-sciatic nerve preparations from the amphibian Xenopus laevis. It was observed that the rate of incorporation of [³H]leucine into protein in DRG and isolated segments of nerve began to increase 9 to 11 h after killing the animal, attaining at 13 to 17 h a maximum of 5- to 10-times preincrease (<9 h) values. At the same time as an increase in the rate of incorporation began, synthesis commenced in DRG and nerve exposed to cycloheximide (125 μg/ml). Whereas cycloheximide reduced fast axonal transport to 1 to 3% of control values in preparations maintained 20 to 24 h in vitro, cycloheximide reduced incorporation in DRG to only 80% of control values. N-terminal labeling studies showed that both the increased incorporation and cycloheximide-insensitive incorporation resulted from protein synthesis. Autoradiographic and incorporation studies indicated that nonneuronal cells situated in the ganglion capsule and perineural sheath of the nerve were responsible for both the increased incorporation and cycloheximide-insensitive synthesis. The findings have implications for the study of axonal transport.     

Changes in cholinergic and opioid receptors in the rat spinal cord,dorsal root and sciatic nerve after ventral and dorsal root lesion

Summary Changes in the distribution of³H-quinuclidinylbenzilate (³ H-QNB),³ H-acetylcholine (³ H-ACh) and³ H-alpha-bungarotoxin (alpha-BTx) binding sites were studied with the use of quantitative in vitro autoradiography in the L4–L6 segments of rats 7 days after ventral L4–L6-rhizotomies and 24 hours after ligation of the dorsal roots L4–L6. The changes in the binding sites of these ligands and of³ H-etorphine binding sites were also studied in the dorsal roots of the rats operated with dorsal root ligation and in the sciatic nerves (around a ligature) in the rats operated with ventral rhizotomy. After ventral rhizotomy³ H-QNB binding sites in the ipsilateral motor neuron area were decreased by about 25% from 100±5 to 73±5 fmol/mg wet weight. After dorsal root ligation³ H-QNB binding sites in the ipsilateral posterior horn were reduced by about 30% from 91±5 to 64±7 fmol/mg wet weight. No significant changes in the binding of the other cholinergic ligands in the spinal cords were observed after the operations. In the dorsal root³ H-alpha-Btx and³ H-etorphine binding sites were higher on the distal side of the ligation (3.5±0.8 and 14±4 fmol/mg wet weight, respectively) than on the proximal side (0.7±0.5 and 2.4±1.2 fmol/mg wet weight, respectively).The same level of³ H-ACh (total, muscarinic and nicotinic) binding was observed on both sides of the ligation. In the sciatic nerve³ H-QNB and total, muscarinic and nicotinic ACh binding sites were higher on the proximal side of the ligation than on the distal side. Except for a small emergence of muscarinic-ACh binding distally to the ligation there were no changes in the number of binding sites in the sciatic nerve after the ventral rhizotomy.Muscarinic antagonist binding sites are probably located on the perikarya of the motor neurons and presynaptically on the primary afferents in the posterior horn and in the dorsal root. Cholinergic agonist binding sites in the spinal cord seem less sensitive to axonal damage than antagonist binding sites. Cholinergic and opioid receptors in peripheral nerves are transported in both anterograde and retrograde directions and their origin seems to be the dorsal root ganglion.     

Cholinergic markers are expressed in developing and mature neurons of chick dorsal root ganglia

The presence of acetylcholinesterase has been reported in chick dorsal root ganglia at early developmental stages although acetylcholine is not known to play a role in these ganglia. Recently, we reported that during development the level of acetylcholinesterase increases continuously and the enzyme becomes gradually expressed in all sensory neurons. These observations prompted the study of the developmental pattern of expression of other cholinergic markers, such as choline acetyltransferase (ChAT) and the high affinity transport mechanism for choline. ChAT activity is barely detectable at early developmental stages (E7) and increases markedly thereafter, with an activity profile similar to that described for acetylcholinesterase. A similar increase in enzyme activity is also observed when ChAT is measured in dorsal root ganglia explants and in dissociated cells in culture. The study of ChAT activity in cultured cells shows an increase over a period of 3 days, thus ruling out the hypothesis that motor fibers, still associated to the ganglia, may represent a possible source of the enzyme. Immunostaining of whole ganglia or cultured cells shows that ChAT immunoreactivity is not restricted to a specific neuronal subpopulation but appears as a common marker of sensory neurons. High affinity choline uptake, blocked by hemicholinium, is present in sensory neurons cultured from E7 dorsal root ganglia. Observations on cultured neurons from later stages (E18) indicate that choline transport is not a transient property of sensory neurons. These observations show a similar pattern of expression of several cholinergic markers during development. Such a pattern is maintained at significant levels also in mature ganglia. © 1994 Wiley-Liss, Inc.     

Neuropathology and blood flow of nerve, spinal roots and dorsal root ganglia in longstanding diabetic rats

Vascular perfusion and neuropathologic evaluation of the lumbar spinal roots and dorsal root ganglia (DRG) were studied in rats with longstanding (duration 12–15 months) streptozotocin-induced diabetes and age- and sex-matched control rats. We also undertook nerve conduction studies including F-wave recordings and measured blood flow in sciatic nerve, DRG, and superior cervical ganglion (SCG). Light microscopically, changes of the myelin sheath in the dorsal and ventral roots and vacuolated cells in the DRG were the major findings, being significantly higher in diabetic rats than in control rats. The effects of the diabetic state on myelin splitting were greater in the dorsal than ventral roots. Electron microscopic studies revealed a gradation of changes in myelin from mild separation to severe ballooning of myelin with relative axonal sparing. DRG cells showed vacuoles of all sizes with cristae-like residues, suggestive of mitochondria. These findings suggest that diabetes mellitus has a dual effect; it accelerates the normal age-related degenerative changes in the spinal roots and DRG, and it also has a selective effect on the sensory neuron. Nerve conduction studies showed markedly reduced conduction velocities in the distal nerve segments and prolonged F-wave latency and proximal conduction time despite the shorter conduction pathway in diabetic rats. Blood flow, which was measured using iodo[¹⁴C]antipyrine autoradiography, was significantly reduced in the sciatic nerves, DRG, and SCG of diabetic rats. We suggest that the combination of hyperglycemia and ischemia results in oxidative stress and a predominantly sensory neuropathy. Received: 26 February 1996 / Revised: 12 June 1996 / Revised, accepted: 13 August 1996     

Exogenous silver in dorsal root ganglia,peripheral nerve,enteric ganglia,and adrenal medulla

Summary Following intraperitoneal (i.p.) or oral administration of silver salts, the anatomic distribution of silver in the peripheral nervous system (PNS) has been studied. The structures examined were dorsal root ganglia, peripheral nerve (N. ischiadicus), enteric ganglia, and adrenal medulla.Four days after an i.p. injection of silver lactate, silver deposits were found in these structures. The silver content remained stable during the observation period (45 days).The localization of silver deposits in the orally treated animals was independent of the administered silver salt (silver nitrate or silver lactate).The silver deposits in neurons and chromaffin cells were located in the cytoplasm. In all organs silver was present in large amounts in connective tissue membranes, macrophage-like cells, vascular basal laminae, and supporting cells. Satellite cells of the dorsal root ganglia were always heavily stained, white less stain was present in Schwann cells of the peripheral nerves.Intracellular deposits were invariably located in lysosomes, whereas extracellular grains were found in connective tissue fibers and basement membranes.     

Non-neuronal cell cultures from dorsal root ganglia of the adult cat: production of schwann-like cell lines

There are several methods available for the production of Schwann cell cultures from fetal or neonatal peripheral nervous tissue. We have investigated methods for producing Schwann cell-rich cultures from adult tissue. Dorsal root gangliafrom normal adult cats were used to initiate explant cultures or subjected to primary dissociation. The resulting cultures were compared in terms of growth, the proportions of fibroblastic and Schwann-like cells in primary cultures and the effects of subculture on the relative frequency of these cell types. We found that excision and transfer of explanted ganglion pieces after 14 days in culture produced a secondary outgrowth rich in small, bipolar, spindle-shaped Schwann-like cells. Subculture of this outgrowth produced secondary cultures of predominantly SChwann-like cells with typical spindle-shaped morphology. The use of antimitotic agents in the media to inhibit fibroblast growth was not observed to be necessary or beneficial with this adult tissue. Primary dissociation of ganglia with enzymes (trypsin or collagenase) and mechanical agitation was even more effective in producing secondary cultures and cell lines that were, by morphological criteria, predominantly or exclusively Schwann-like cells. One of these Schwann-like cell lines, designated GSA, has been carried over 24 subcultures while retaining characteristics Schwann cell morphology. Cells of this line have been examined by scanning and transmission electron microscopy. Karyotype analysis indicates a chromosome complement consistent with the species of origin, a normal cat.     

Regeneration of primary sensory axons into the adult rat spinal cord via a peripheral nerve graft bridging the lumbar dorsal roots to the dorsal column

This study investigated the feasibility of using a peripheral nerve autograft (NAG) to promote and guide regeneration of sensory axons from the caudal lumbar dorsal roots to the rostral dorsal column following a lower thoracic cordotomy in adult rats. After a left hemicordotomy at the T13 vertebra level and ipsilateral L3 and L4 rhizotomies, a peripheral NAG (peroneal nerve) was connected to the distal roots stumps, then implanted into the left dorsal column 10 mm rostral to hemicordotomy site (n = 12). After surgery, all animals of the experimental group experienced complete anesthesia in their left hindlimb. Three months later, a slight response to nociceptive stimulation reappeared in L3 and/or L4 dermatomes in 6 of the 12 experimental animals. None of these animals exhibited self-mutilation. Nine months after surgery, we performed retrograde tracing studies by injecting horseradish peroxidase (HRP) into the left dorsal column 30 mm rostral to the NAG implantation site. In eight animals, we found HRP-stained neurons in the left L3 and/or L4 dorsal root ganglia (DRG). The mean number of HRP-stained neurons per DRG was 71 +/- 92 (range 2-259). In control groups, no HRP-stained neurons were found in L3 or L4 DRG. Histological analysis of the NAG showed evidence of axonal regeneration in all 8 animals with positive retrograde labeling of DRG neurons. However, we did not find a statistical correlation between the number of HRP-stained neurons and the degree of sensory recovery. This study demonstrates that an NAG joining dorsal roots to the dorsal column, thus shunting the original CNS-PNS junction, can support regeneration of central axons from DRG primary sensory neurons into the dorsal column over distances of at least 30 mm despite the inhibitory influence of the CNS white matter.     

Hypoplasia of posterior spinal roots and dorsal spinal tracts with arthrogryposis multiplex congenita

Summary We report a male infant with arthrogryposis multiplex congenita (AMC) who survived for 19 weeks following birth at 36 weeks gestational age. No heritable or acquired cause of neuromuscular disease was found. He manifested joint contractures of upper and lower extremities, diffuse hypotonia requiring ventilatory support, and areflexia; the general examination also showed facial dysmorphisms, and an ichthyotic rash. Pathological examination of the brain and spinal cord revealed severe hypoplasia of dorsal roots and posterior columns, nondecussation of pyramidal tracts, and anterior horns of an unusual configuration: the brain was normal, and the cerebellum contained Purkinje cell heterotopias. Muscle spindles could not be identified. To our knowledge, these spinal cord abnormalities in association with AMC have not been previously reported, thus raising interesting speculations about the possible role of such abnormalities in the pathogenesis of AMC.     

Different types of spinal afferent nerve endings in stomach and esophagus identified by anterograde tracing from dorsal root ganglia

In visceral organs of mammals, most noxious (painful) stimuli as well as innocuous stimuli are detected by spinal afferent neurons, whose cell bodies lie in dorsal root ganglia (DRGs). One of the major unresolved questions is the location, morphology, and neurochemistry of the nerve endings of spinal afferents that actually detect these stimuli in the viscera. In the upper gastrointestinal (GI) tract, there have been many anterograde tracing studies of vagal afferent endings, but none on spinal afferent endings. Recently, we developed a technique that now provides selective labeling of only spinal afferents. We used this approach to identify spinal afferent nerve endings in the upper GI tract of mice. Animals were anesthetized, and injections of dextran‐amine were made into thoracic DRGs (T8–T12). Seven days post surgery, mice were euthanized, and the stomach and esophagus were removed, fixed, and stained for calcitonin gene‐related peptide (CGRP). Spinal afferent axons were identified that ramified extensively through many rows of myenteric ganglia and formed nerve endings in discrete anatomical layers. Most commonly, intraganglionic varicose endings (IGVEs) were identified in myenteric ganglia of the stomach and varicose simple‐type endings in the circular muscle and mucosa. Less commonly, nerve endings were identified in internodal strands, blood vessels, submucosal ganglia, and longitudinal muscle. In the esophagus, only IGVEs were identified in myenteric ganglia. No intraganglionic lamellar endings (IGLEs) were identified in the stomach or esophagus. We present the first identification of spinal afferent endings in the upper GI tract. Eight distinct types of spinal afferent endings were identified in the stomach, and most of them were CGRP immunoreactive. J. Comp. Neurol. 524:3064–3083, 2016. © 2016 Wiley Periodicals, Inc.     

Alteration of P2X3 expression in dorsal root ganglia after sciatic nerve ligation

BACKGROUND: The expressions of P2X3 receptor in dorsal root ganglia (DRG) after different peripheral nerve injuries are diverse. It indicates the different roles of P2X3 in different models-caused neuropathologic pains. OBJECTIVE: To observe the expressions of P2X3 in corresponding DRG after sciatic nerve ligation in rats. DESIGN: Controlled observation experiment. SETTING: Department of Morphology, Hunan Traditional Chinese Medical College; Department of Human Anatomy and Neurobiology, Xiangya Medical College, Central South University. MATERIALS: Thirty-five healthy adult SD rats of clean grade an d either gender, weighing （200±20）g, were involved. According to the random digits table, the involved rats were randomized into 3 groups: normal group (n =5), sham-operated group (n =5) and experimental group (n =25). The experimental group were subdivided into 3,7,14,21,28 days groups according to different surviving time after operation, 5 rats at each time point. Polyclonal rabbit anti-P2X3 antibody (ABCAM company); biotinylated goat anti-rabbit IgG (Zhongshanjingqiao Biotechnical Co., Ltd., Beijing); Motic fluorescence microscope (Motic, Germany). METHODS: The experiments were carried out in the Department of Human Anatomy and Neurobiology, Xiangya Medical College, Central South University from June to December 2006. ① Rats of experimental group were created into models by ligation of right sciatic nerve according to the method of Seltzer et al. Left sciatic nerve was used as self-control. As for rats in the sham-operated group, ligation of sciatic nerve was omitted, but other procedures were the same as those in the experimental group. Rats of normal group were untouched. ② Rats of the normal group and sham-operated group survived for 14 days separately, and those of experimental group survived for corresponding time. After being deeply anesthetized by intraperitoneal injection of over-dose sodium pentobarbital, the rats of experimental group were transcardially perfused. L4–6 corresponding DRG connected to sciatic nerve were taken for preparing transverse sections serially. ③P2X3 expression in L4–6 DRG was detected by immunohistochemistry, immunofluorescence and image analysis techniques. MAIN OUTCOME MEASURES: P2X3 expression in L4–6 DRG of rats in each group. RESULTS: Thirty-five SD rats were involved in the final analysis. ① P2X3 expression in DRG: In normal DRG of rats, there were abundant P2X3 immuno-positive small- and medium-sized primary sensory neurons, especially the small ones, which mostly received the input from C fibers. There were only a few large neurons expressing P2X3. The immuno-positive products mostly were located in the cytoplasm and processes. The expression of P2X3 had a slight but significant decrease in ipsilateral L4–6 DRG 3 days after sciatic nerve ligation, and a decreasing tendency was observed with the elongation of time. At 28 days, the expression had not returned to base line, and still maintained at a low level. ② P2X3 immuno-positive gray scale in DRG: P2X3 immuno-positive gray scale in ipsilateral side L4–6 DRG was 117.74±2.38,129.12±4.86,133.56±3.79,148.75±6.90 and 150.49±5.15, respectively at 3,7,14, 21 and 28 days after sciatic nerve ligation, which was significantly higher than that in the normal group and sham-operated group （105.11±3.52,104.22±5.41,F =78.861,P < 0.05）, also significantly higher than that in the contralateral side （105.53±5.85,108.54±3.70,104.07±4.16,106.55±2.02,106.29±5.19,t =3.48–13.95,P < 0.05）; There were no significant differences when comparing sham-operated group or contralateral side at each time point with normal group (P > 0.05) CONCLUSION: P2X3 is significantly down regulated in L4–6 DRG after sciatic nerve ligation. It may exert certain effects in neuropathic pain.     

Vasoactive intestinal polypeptide identified in the thoracic dorsal root ganglia of the cat

Neurons which exhibited vasoactive intestinal polypeptide (VIP) immunoreactivity were identified with immunohistochemical techniques in the cat thoracic dorsal root ganglia (DRG, T8-T11) injected with colchicine 2 days prior to sacrifice. VIP-positive cells (5-40 cells per section) were small to medium size ranging from 14-41 micron in diameter. VIP-immunoreactivity was weaker in the thoracic DRG exposed to colchicine by topical administration. The neuropeptide could not be detected in the thoracic DRG (T1-T13) in the absence of colchicine. VIP-immunoreactivity was also identified in the superficial laminae (I and II) of the thoracic spinal cord. The findings indicate that VIP in afferent pathways in the cat is distributed more extensively than previously reported and is not restricted only to the lower lumbar and sacral levels of the spinal cord.     

Evidence of substance P immunoreactive neurons in dorsal root ganglia and vagal ganglia projecting to the guinea pig pylorus

The origin of extrinsic substance P fibers in the guinea pig pyloric wall was investigated by combining retrograde axonal tracing and indirect immunofluorescence techniques. After injection of Fast Blue into the pyloric wall labeled cells were found in the T7-T9 dorsal root ganglia and the nodose and jugular ganglia. About 60% of the labeled cells in the dorsal root ganglia contained substance P-like immunoreactivity. After local application of colchicine, a few substance P positive cells were observed in the nodose and jugular ganglia, some of which also contained Fast Blue.