Treatment with 6-hydroxydopamine and colchicine decreases nerve growth factor levels in sympathetic ganglia and increases them in the corresponding target tissues

A two-site enzyme immunoassay was used to determine the nerve growth factor (NGF) contents of sympathetic ganglia and their corresponding target tissues in adult rats. The destruction of sympathetic nerve terminals by 6-hydroxydopamine (6-OHDA) and the blockade of axonal transport by colchicine resulted in a rapid increase in the NGF levels of sympathetically innervated organs and a rapid decrease in the sympathetic ganglia. NGF levels in heart atrium, heart ventricle, submandibular gland, and iris increased 2- to 4-fold 12 hr after injection of 6-OHDA, whereas the NGF contents of stellate and superior cervical ganglia dropped to a minimal level of 3 to 4% of control 24 hr after injection. Twelve hours after treatment with colchicine the NGF levels in sympathetically innervated organs increased 2- to 3-fold, whereas the NGF contents of sympathetic ganglia fell to one-third of control values. The half-lives of NGF in the superior cervical and stellate sympathetic ganglia were 4.5 and 4.8 hr, respectively, as determined by the decrease of NGF content after treatment with 6-OHDA. These results indicate that the synthesis of NGF is normally confined to the innervated target organs with no significant contribution of ganglionic cells. This is consistent with the concept that NGF acts as a retrograde messenger between target organs and innervating sympathetic neurons.     

Sympathetic postganglionic innervation of the cardiac coronary artery in cats

The localization of the sympathetic postganglionic neurons innervating the cardiac coronary arteries of the cat was investigated using retrograde axonal transport with horseradish peroxidase. We found after the enzyme was applied to the main trunk of the right coronary artery, and to the main trunk and the terminal branch of the ventral descending vessels of the left coronary artery, the peroxidase-labeled sympathetic neurons were localized predominantly in the right stellate ganglia, with a few cells in the left stellate ganglia. There were very few labeled cells in the middle cervical, superior cervical, and T4-7 ganglia on both sides. After peroxidase application to the terminal branch of the dorsal descending vessels of the right coronary artery, labeled cells were mainly in the left stellate ganglia, with only a few cells in the right stellate ganglia.     

Differential susceptibility of prevertebral and paravertebral sympathetic ganglia to experimental injury

To investigate the response of selected sympathetic ganglia to experimental injury, neonatal rat pups were treated with either 6-hydroxydopamine (6-OHDA), guanethidine, or antiserum to nerve growth factor (anti-NGF). When examined at one month of age, each of the treatments resulted in a significantly greater loss of neurons and tyrosine hydroxylase activity in paravertebral (superior cervical and stellate) versus prevertebral (superior mesenteric and celiac) sympathetic ganglia. Guanethidine treatment produced the largest differential in neuron loss and tyrosine hydroxylase activity between pre- and paravertebral ganglia. Histologically, the acute phase of guanethidine-induced injury in the superior cervical, paravertebral, ganglia was characterized by a prominent mononuclear cell infiltrate and extensive neuronal degeneration. Minimal histopathologic changes were seen in the superior mesenteric, prevertebral, ganglia of the same animals. Immunolocalization of tyrosine hydroxylase and neuropeptide Y (NPY) in guanethidine-treated animals showed a preferential loss of sympathetic innervation of the extramural mesenteric vasculature with relative sparing of the noradrenergic innervation of Auerbach's myenteric plexus. Differences in the susceptibility of sympathetic ganglia to various insults may underlie the selective and heterogeneous involvement of sympathetic ganglia in clinical and experimental situations.     

The sympathetic trunks of a hibernator, the bat Myotis lucifugus

The sympathetic trunks in Myotis lucifugus are each characterized by three unusually prominent ganglia: the superior cervical, the stellate and a “large lumbar” ganglion. The superior cervical appears to distribute only to the head region. The cervical sympathetic trunk connects with the vagus nerve but not to the cervical spinal nerves. The stellate is the largest of the trunk ganglia. A prominent nerve arising from it follows the vertebral artery. This vertebral nerve connects with the second to the seventh, and sometimes the eighth, cervical spinal nerves. Another prominent branch from this ganglion follows the cervical artery to ramify in the interscapular brown fat pad. The stellate ganglion supplies the brachial plexus directly and via the vertebral nerve. Its branches also supply thoracic viscera important for arousal from hibernation as well as for flight. The large lumbar ganglion contributes very few fibers to abdominal or pelvic viscera but, via the lumbosacral plexus, may affect vasoconstriction in the pelvic wall and posterior extremities. The prominent prevertebral ganglia in the abdomen and pelvis, which include an adrenal-;renal complex, are probably supplied by the tenth thoracic to second lumbar spinal nerves.     

Peptide-containing neurons projecting to the vocal cords of the rat: retrograde tracing and immunocytochemistry

The distribution and origin of neuropeptide Y-, vasoactive intestinal peptide- and calcitonin gene-related peptide-containing nerve fibers and adrenergic (dopamine-beta-hydroxylase-containing) fibers in the rat larynx were studied by retrograde tracing and selective denervations in combination with immunocytochemistry. An injection of the retrograde tracer True Blue to the right vocal cord resulted in the appearance of labelled nerve cell bodies in the ipsi- and contralateral superior cervical and stellate ganglia, the thyroid ganglia, the jugular-nodose ganglionic complexes, in the ipsilateral trigeminal and dorsal root ganglia at levels C2 and C3 and in local tracheal ganglia. Judging from the number of labelled nerve cell bodies, the jugular-nodose ganglionic complexes, dorsal root ganglia and superior cervical ganglia provide the greater part of the vocal cord innervation. Most of the True Blue-labelled nerve cell bodies in the superior cervical and stellate ganglia contained neuropeptide Y. In the thyroid ganglia the majority of labelled nerve cell bodies contained vasoactive intestinal peptide. In the jugular-nodose ganglionic complex and the dorsal root ganglia the majority of the labelled nerve cell bodies stored calcitonin gene-related peptide. Retrograde tracing and denervation studies revealed that all noradrenaline- and the majority of neuropeptide Y-containing nerve fibers emanate from the superior cervical and stellate ganglia. A minor population of neuropeptide Y-containing nerve fibers originate in local tracheal ganglia. The vasoactive intestinal peptide-containing nerve fibers originate in the thyroid ganglion and local tracheal ganglia, whereas calcitonin gene-related peptide-containing nerve fibres emanate from the dorsal root ganglia (C2-C3), the trigeminal ganglia and the jugular-nodose ganglia.     

Secretoneurin-like immunoreactivity in rat sympathetic, enteric and sensory ganglia

Distribution of secretoneurin-like immunoreactivity (SN-LI) was studied in the rat sympathetic ganglia/adrenal gland, enteric and sensory ganglia by immunohistochemical methods. SN-LI nerve fibers formed basket-like terminals surrounding many of the postganglionic neurons of the superior cervical, stellate, paravertebral chain ganglia, coeliac/superior mesenteric and inferior mesenteric ganglia. Postganglionic neurons of the superior cervical and other sympathetic ganglia exhibited low-to-moderate levels of SN-LI. In all these sympathetic ganglia, clusters of small diameter (<10 μm) cells, which may correspond to the small intensely fluorescent (SIF) cells, were found to be intensely labeled. Surgical sectioning or ligation of the cervical sympathetic trunk for 7–10 days resulted in a nearly total loss of SN-LI fibers in the superior cervical ganglia, whereas immunoreactivity in the postganglionic neurons and small diameter cells remained essentially unchanged. In the thoracolumbar and sacral segments of the spinal cord, SN-LI nerve fibers were detected in the superficial layers of the dorsal horn as well as in the intermediolateral cell column (IL_p). Occasionally, SN-LI somata were noted in the IL_p. SN-LI nerve fibers formed a delicate plexus underneath the capsule of the adrenal gland, some of which traversed the adrenal cortex and reached the adrenal medulla. While heavily invested with SN-LI nerve terminals, chromaffin cells seemed to express a low level of SN-LI. In the enteric plexus, varicose SN-LI nerve fibers and terminals formed a pericellular network around many myenteric and submucous ganglion cells; the ganglionic neurons were lightly to moderately labeled. A population of ganglion cells in the dorsal root, nodose and trigeminal ganglia exhibited moderate-to-strong SN-LI. The detection of SN-LI in nerve fibers and somata of various sympathetic ganglia, enteric plexus and adrenal medulla and in somata of the sensory ganglia implies an extensive involvement of this peptide in sympathetic, enteric and sensory signal processing.     

Is CRF a ganglionic transmitter or modulator in the cat sudomotor pathway?

The presence of corticotrophin releasing factor (CRF)-like immunoreactivity distinguishes a subset of cat sympathetic preganglionic neurons which supplies sweat glands. It is abundant in their terminals in the stellate ganglion. We sought first to determine whether this immunoreactivity is due to true CRF, then to test whether CRF plays any role in ganglionic transmission in the cat sudomotor pathway. CRF-immunoreactive material extracted from cat stellate ganglia and hypothalamus were eluted on HPLC at equivalent retention times, slightly less than that of standard sheep CRF. In chloralose-anaesthetised cats, sheep CRF (0.13, 1.3 and 13 μg/kg, i.v.) raised plasma immunoreactive ACTH levels by between 3- and 300-fold. Submaximal stimulus trains delivered to pre- or postganglionic nerves of the right stellate ganglion evoked electrodermal response (EDR, a measure of sweat gland activity) in the right forepaw pad as well as increases in heart rate and blood pressure. Exogenous sheep CRF (dose range 130 ng/kg to 13 mg/kg) given close-arterially to the stellate ganglion in 5 chloralose-anaesthetised cats had no consistent effect on either baseline or preganglionically-evoked EDR. Given i.v. at 13 μg/kg to four further cats, sheep CRF caused no significant change in mean baseline or mean preganglionically-evoked EDP (P > 0.05; CUSUM test). Hexamethonium (10 or 30 mg/kg i.v.) abolished the EDR to preganglionic nerve stimulation (7/7 cats). Increasing preganglionic stimulus voltage, frequency and train duration failed to show any hexamethonium-resistant component of the EDR, although such effects were evident in the cardioaccelerator pathway. We conclude that cat preganglionic sudomotor neurons contain true CRF, although the cat peptide is not identical to that of the sheep. Exogenous CRF had no measurable effect on postganglionic neurons or on ganglionic transmission in the cat sudomotor pathway. Ganglionic transmission in the sudomotor pathway, unlike that to the heart, is entirely nicotinic. The function of CRF in cat sudomotor pathway remains unknown.     

Horseradish peroxidase localization of the sympathetic postganglionic neurons innervating the cat heart

The localization of the sympathetic postganglionic neurons innervating the cat heart has been investigated by using retrograde axonal transport of horseradish peroxidase (HRP). HRP was injected into the subepicardial layers of 4 different cardiac regions. The animals were sacrificed 72-96 h later and fixed by perfusion via the left ventricle. The paravertebral sympathetic ganglia from the superior cervical, middle cervical and stellate ganglia to T10 ganglia were removed and processed for HRP identification. Following injections of HRP into the apex of the heart, the sinoatrial (SA) nodal region and the ventral wall of the right ventricle, we observed that HRP-labeled sympathetic neurons were localized predominantly in the right stellate ganglia, and to a lesser extent, in the right superior and middle cervical ganglia, and left stellate ganglia. Fewer labeled cells were found in the right T4-T6. T8 and T9. After HRP injection into the dorsal wall of the left ventricle, HRP-labeled cells were present mainly in the left stellate ganglia.     

Action of delta 9 tetrahydrocannabinol on the central cardiovascular regulation : mechanism and localization]

Delta9-tetrahydrocannabinol (30-300 mug.kg-1 i.v.) induced in cats and dogs a decrease in blood pressure and heart rate. This decrease appears to be centrally mediated. In fact, the splanchnic and cardiac discharges were reduced in intact animals as well as in debuffered cats ruling out a reflexly mediated action. The mechanism of this central decrease in the sympathetic tone appears to be different from the mechanism of the reduction induced by clonidine or by narcotic analgesics agents. In fact, piperoxan (1 mg.kg-1 i.v.), an alpha adrenoceptor blocking agent, antagonized or reversed the centrally mediated reduction in the sympathetic tone induced by clonidine or L-dopa, but did not change the effects of narcotic analgesic agents and of delta9-tetrahydrocannabinol. Naloxone (30 mug.kg-1 i.v.) prevented or reversed the cardiovascular effects of fentanyl and the reduction in splanchnic discharges induced by this agent, but no change was found after naloxone in the effects of clonidine or delta9-tetrahydrocannabinol. The pressor response to high frequency stimulation of the medulla oblongata was abolished by small doses of delta9-tetrahydrocannabinol. This agent did not reduce the pressor response to stimulation of the posterior hypothalamus induced by supramaximal stimulation and did not alter the hypertensive effect induced by stimulation of the cervical spinal cord. Medulla oblogata appears therefore to be the main site of action.     

Molecular mechanisms of neuroendocrine integration in the central nervous system: An approach through the study of the pineal gland and its innervating sympathetic pathway

In the brain specialized cells known as ‘neuroendocrine transducers’ translate an input of neural activity into a hormonal output, e.g. oxytocin released into the blood stream. Other, more typical neurons make the reverse conversion constituting chemoreceptors which transform the hormonal ‘language’ into changes in their firing rate (‘endocrine - neural’ transduction). ‘Endocrine-endocrine’ transducing events occur at the level of the neurosecrotary cells that translate a hormonal signal into another, different, hormone output. This article reviews the molecular aspects of several neuroendocrine integrative processes in the hypothalamus, the pineal gland and the cervical sympathetic pathway. The discussed results indicate that the pineal gland and its innervating sympathetic neurons located in the superior cervical ganglia constitute an easy-to-manipulate model system for the study of basic neuroendocrine mechanisms because: (i) receptors for various hormones exist in the mammalian pineal and sympathetic ganglia; (ii) the pattern of pineal steroid metabolism resembles that of the neuroendocrine hypothalamus; (iii) pineal estrophilic and androphilic receptors as well as the pattern of steroid metabolism are modulated by the sympathetic nerves; (iv) neuronal activity in the cervical sympathetic pathway is modified by hormone treatment at preganglionic, ganglionic and postganglionic sites.     

Histopathological examination of chemo-sympathectomy in cats

In recent decades, there has been an increase in both the number of sympathectomy techniques, as well as the surgical findings of sympathetic anatomy. Currently the advanced technique of C-arm guided percutaneous thoracic chemo-sympathectomy is widely used for the treatment of palmar hyperhidrosis. However, a better understanding of chemical agents in sympathectomy is required. In this study, chemo-sympathectomy was performed in cats, using alcohol, glycerol and various concentrations of phenol, to determine the chronic neurotoxic effects of these chemical agents on the stellate ganglia. The stellate ganglia of 24 cats were exposed under endotracheal general anesthesia, then injected with about 0.02 ml of absolute alcohol, glycerol and phenol (10%, 25%, 50%, and 75% concentration) solutions, respectively. The stellate ganglia were taken for histological examination three weeks after the chemical injection. The results showed that the degenerative changes in the cytoplasm and nucleus of ganglionic cells and intercellular tissue were moderate and relatively moderate after the injection of alcohol and glycerol, respectively. Meanwhile, the stellate ganglia revealed mild, relatively moderate, serious and extremely serious degeneration after injection of 10%, 25%, 50%, and 75% phenol, respectively. In conclusion, we recommend a high concentration of phenol, in the least volume, as a chemical agent for clinical injection in the upper thoracic sympathetic ganglion.     

Distribution of neuropeptide-like immunoreactivity in intact and chronically decentralized middle cervical and stellate ganglia of dogs

Neuropeptide-like immunoreactivity to antisera raised against Leu- and Met-enkephalin, vasoactive intestinal peptide (VIP), neuropeptide Y (NPY) and substance P (SP) have been studied immunohistochemically in middle cervical and stellate ganglia of dogs. To investigate the relationship of the peptides to one another as well as to preganglionic and postganglionic neurons, intact and chronically decentralized middle cervical and stellate ganglia were studied. Ganglia were processed for immunohistochemistry in unoperated dogs and in dogs two weeks after unilateral ganglionic decentralization. The immunoreactivity for each peptide had a characteristic distribution in the ganglia. These distributions differed from one another and from the distribution of cardiac postganglionic sympathetic neurons. Camera lucida drawings of peptide distributions were made to compare different peptides and counts were made to determine the percentages of cells immunoreactive for a given peptide. The results demonstrated that enkephalin-like immunoreactivity in axons was present in both the stellate and middle cervical ganglia, but was heaviest in the caudal 2/3 of the stellate ganglia. Enkephalin-like immunoreactive fibers formed pericellular baskets around stellate ganglion neurons. VIP-like immunoreactive cell bodies and processes were distributed sparsely, but widely, in the stellate ganglia and to a lesser extent in the middle cervical ganglia. One of two commercial antisera to SP resulted in immunoreactive staining of cell bodies and processes in the stellate ganglia. SP-like immunoreactivity in neurons represented about 10% or less of the cells in the stellate ganglia. At least 80-85% of the neurons in the stellate and middle cervical ganglia were immunoreactive for NPY antisera. Decentralization eliminated enkephalin-like immunoreactive staining in the middle cervical and stellate ganglia, but not the VIP-, NPY- and SP-like immunoreactive staining of neurons in these ganglia. In summary, the enkephalin-like immunoreactive axons in the thoracic autonomic ganglia appear to be derived from extrinsic neurons, most likely from preganglionic spinal neurons. VIP-, SP- and NPY-like immunoreactivity were not significantly affected by decentralization. The results provide anatomical evidence for substrates related to neuropeptidergic synaptic mechanisms in thoracic autonomic ganglia.     

Calbindin-D28k immunoreactivity in sympathetic ganglionic neurons during development

Expression of CB in the sympathetic ganglia was investigated by immunohistochemistry. The distribution of CB immunoreactivity was studied in the superior cervical ganglion (SCG), stellate ganglion (SG) and celiac ganglion (CG) from rats and cats of different ages (newborn, 10-day-old, 20-day-old, 30-day-old, two-month-old, six-month-old). We observed that the percentage of CB-immunoreactive (IR) neurons decreased during early postnatal development in rats and cats. In all studied ganglia of both species, the percentage of CB-IR neurons was high in newborn and 10-day-old animals and significantly decreased up to 30 days of life. In rats of all ages, the largest percentage of CB-IR neurons was observed in the SG compared to the SCG and CG. In the cat sympathetic ganglia, the number of CB-IR neurons decreased more rapidly during the first two months of life, and only scattered CB-IR neurons were found in the sympathetic ganglia of two-month-old and six-month-old cats. In cats, the highest percentage of CB-IR neurons was observed in the SG, while the lowest percentage was found in the CG. The difference in size between CB+ and CB- neurons equally changed during development. Finally, the changes in the size and percentages of CB-IR neurons were complete in rats at the first month of life, and in cats at the end of the second month.     

The role of vasopressin in the pressor response to bilateral carotid occlusion

Exogenous arginine vasopressin (AVP) has been shown to interact with the arterial baroreflex control of renal sympathetic nerve activity. In addition, we have shown that both AVP and the sympathetic nervous system (SNS) contribute to the pressor response to interruption of cardiopulmonary vagal afferents. This study examined the role and interaction of AVP and the SNS in the pressor response to a reduction of carotid sinus afferent activity by bilateral carotid occlusion (BCO). In addition the role of the area postrema (AP) in mediating the interaction between AVP and the SNS was examined. In aortic denervated conscious dogs, BCO increased mean arterial pressure 51.7 +/- 3.1 mm Hg. Specific vascular (V1) AVP antagonist D(CH2)5Tyr(Me)AVP did not alter the response to BCO (delta 50.8 +/- 7.9 mm Hg). Subsequent ganglionic blockade abolished the response to BCO (delta -10 +/- 3.8). When ganglionic blockade was induced in the absence of AVP antagonist, BCO increased MAP 25.0 +/- 2.8 mm Hg. AVP antagonist following ganglionic blockade eliminated the pressor response to BCO (delta -6.7 +/- 5.1). There was an interaction between AVP and the SNS such that the contribution of one system to the hemodynamic response was greater in the absence of the other system. Ablation of the AP abolished the interaction between reflexly released AVP and the SNS which was observed in intact dogs. These data demonstrate that both AVP and the SNS contribute to the pressor response to BCO. Reflexly released AVP appears to limit the reflex activation of the SNS. The interaction of endogenous AVP and the arterial baroreflex involves the AP. The results are consistent with the hypothesis that vasopressin interacts centrally to limit a reflex increase in sympathetic outflow and thus modulate the pressor response to BCO.     

Evidence for a sympathetic component in motor branches of the facial nerve: a horseradish peroxidase study in the cat

The retrograde transport of horseradish peroxidase (HRP) was used to examine the location of sympathetic ganglion cells with axons in facial motor branches of the cat. Large numbers of HRP-labeled neurons were observed in the rostro-anterior part of the superior cervical ganglion. In addition, some labeled neurons were found in the cervical sympathetic trunk, the accessory cervical, middle cervical and stellate ganglia.     

Specific angiotensin II binding sites in the rat stellate and superior cervical ganglia

Angiotensin II binding sites were localized and quantified in rat stellate and superior cervical ganglia by quantitative autoradiography using 125I-Sar1-angiotensin II as a ligand. Both ganglia possess a single class of angiotensin II binding sites. High concentrations of binding sites were localized in the areas rich in principal ganglion cells. These binding sites might mediate the facilitatory action of angiotensin II on the ganglionic transmission.     

Selective pharmacological blockade of parasympathetic and enteric ganglia.

The blocking effects of two newly synthetized compounds, diisopropyldecylammonium iodide (IEM-1194) and 2,2,6,6-tetramethyldecylpiperidinium chloride (IEM-1559), on insulin- and pentagastrin-induced gastric secretion in chronic dogs, on stress-induced changes in gastric mucosa in rats, on vagus-induced effects in heart and intestine, on arterial blood pressure and on synaptic transmission through isolated ciliary and superior cervical ganglia in cats were studied. The effects observed were compared with those produced by hexamethonium (C6), a conventional ganglionic blocking agent. Both IEM-1194 and IEM-1559 inhibited gastric secretion and acid output for a much longer time than C6 did and effectively protected gastric mucosa against stress-induced erosions and hemorrhages. IEM-1194 blocked the vagus-induced decrease in heart rate and increase in duodenal motility for a longer time than did C6 and also, in contrast to C6, did not reduce the arterial blood pressure. The blockade of synaptic transmission through isolated ciliary and superior cervical ganglia produced by IEM-1194 and IEM-1559 was characterized by lower EC50 and was more prolonged than that produced by C6. In addition, both IEM-1194 and IEM-1559 were more potent blocking agents in ciliary ganglion than in superior cervical ganglion. It is suggested that IEM-1194 and IEM-1559 are selective blocking agents for parasympathetic and enteric ganglia versus sympathetic ganglia.     

A general pattern of CNS innervation of the sympathetic outflow demonstrated by transneuronal pseudorabies viral infections

Pseudorabies virus (PRV) injections of various sympathetic ganglia and the adrenal gland were made in rats. These produced immunohistochemically detectable retrograde viral infections of ipsilateral sympathetic preganglionic neurons (SPNs) and transneuronal infections of the specific sets of second order neurons in the spinal cord and brain that innervate the infected SPNs. Five cell groups in the brain appear to regulate the entire sympathetic outflow: the paraventricular hypothalamic nucleus (PVH), A5 noradrenergic cell group, caudal raphe region, rostral ventrolateral medulla, and ventromedial medulla. In addition, local interneurons in laminae VII and X of the spinal cord are also involved. Other CNS areas also became transneuronally labeled after infections of certain sympathetic ganglia, most notably the superior cervical and stellate ganglia. These areas include the central gray matter and lateral hypothalamic area. The zona incerta was uniquely labeled after stellate ganglion infections. The cell body labeling was specific. This specificity was demonstrated in the PVH where the neurons of the parvocellular PVH that form the descending sympathetic pathway were labeled in a topographic fashion. Finally, we demonstrate that the retrograde transneuronal viral cell body labeling method can be used simultaneously with either neuropeptide transmitter or transmitter synthetic enzyme immunohistochemistry.     

Spinal origin of sympathetic preganglionic neurons in the rat

The segmental distribution of sympathetic preganglionic neurons (SPNs) and dorsal root ganglion cells (DRGs) was studied after Fluoro-gold injections into the major sympathetic ganglia and adrenal gland in rats. A quantitative assessment of the segmental and nuclear locations was made. Four general patterns of innervation were apparent: (1) a large number of SPNs (1000–2000/ganglion) innervate the sympathetic ganglia which control head or thoracic organs and a relatively small number of SPNs (100–400/ganglion) innervate the sympathetic ganglia controlling the gut, kidney, and pelvic organs; this difference in density of innervation probably relates to the level of fine control that can occur in these end organs by the SPNs; (2) the reverse pattern is seen in the DRG labeling where a large number of DRGs were labeled after Fluoro-gold injections into the preaortic ganglia (celiac, superior, and inferior mesenteric) and a small number were labeled after injections into the cervical sympathetic ganglia; (3) the intermediolateral cell column is the main source of SPNs except for the inferior mesenteric ganglion which is innervated predominantly by SPNs originating in the central autonomic nucleus (75%); the lateral funiculus is a source of SPNs mainly for the cervical sympathetic ganglia; and (4) each sympathetic ganglion and the adrenal gland receives a multisegmental SPN and DRG input with one segment being the predominant source of the innervation. The adrenal gland shows an intermediate position in terms of the density of SPN input (800 cells) and dorsal root input (300 cells); it has a widespread segmental input (T₄-T₁₂) with the T₈ segment being the major source.