Thoracic sympathetic nuclei ischemia: Effects on lower heart rates following experimentally induced spinal subarachnoid hemorrhage.

BACKGROUND: The neuropathological mechanism of heart rhythm disorders, following spinal cord pathologies, to our knowledge, has not yet been adequately investigated. In this study, the effect of the ischemic neurodegeneration of the thoracic sympathetic nuclei (TSN) on the heart rate (HR) was examined following a spinal subarachnoid hemorrhage (SSAH). METHODS: This study was conducted on 22 rabbits. Five rabbits were used as a control group, five as SHAM, and twelve as a study group. The animals' HRs were recorded via monitoring devices on the first day, and those results were accepted as baseline values. The HRs were remeasured after injecting 0.5 cc of isotonic saline for SHAM and 0.5 cc of autolog arterial blood into the thoracic spinal subarachnoid space at T4-T5 for the study group. After a three-week follow-up with continuous monitoring of their HRs, the rabbit's thoracic spinal cords and stellate ganglia were extracted. The specimens were evaluated by histopathological methods. The densities of degenerated neurons in the TSN and stellate ganglia were compared with the HRs. RESULTS: The mean HRs and mean degenerated neuron density of the TSN and stellate ganglia in control group were 251±18/min, 5±2/mm3, and 3±1/mm3, respectively. The mean HRs and the mean degenerated neuron density of the TSN and stellate ganglia were detected as 242±13/min, 6±2/mm3, and 4±2/mm3 in SHAM (P>0.05 vs. control); 176±19/min, 94±12/mm3, and 28±6/mm3 in the study group (P<0.0001 vs. control and P<0.005 vs. SHAM), respectively. CONCLUSIONS: SAH induced TSN neurodegeneration may have been responsible for low HRs following SSAH. To date this has not been mentioned in the literature.

Ethanol-Induced Cervical Sympathetic Ganglion Block Applications for Promoting Canine Inferior Alveolar Nerve Regeneration Using an Artificial Nerve.

Polyglycolic acid collagen (PGA-C) tubes are bio-absorbable nerve tubes filled with collagen of multi-chamber structure, which consist of thin collagen films. Favorable clinical outcomes have been achieved when using these tubes for the treatment of damaged inferior alveolar nerve (IAN). A critical factor for the successful nerve regeneration using PGA-C tubes is blood supply to the surrounding tissue. Cervical sympathetic ganglion block (CSGB) creates a sympathetic blockade in the head and neck region thus increasing blood flow in the area. To ensure an adequate effect, the blockade must be administered with local anesthetics one to two times a day for several consecutive weeks; this poses a challenge when creating animal models for investigating this technique. To address this limitation, we developed an ethanol-induced CSGB in a canine model of long-term increase in blood flow in the orofacial region. We examined whether IAN regeneration via PGA-C tube implantation can be enhanced by this model. Fourteen Beagles were each implanted with a PGA-C tube across a 10-mm gap in the left IAN. The IAN is located within the mandibular canal surrounded by bone, therefore we chose piezoelectric surgery, consisting of ultrasonic waves, for bone processing, in order to minimize the risk of nerve and vessel injury. A good surgical outcome was obtained with this approach. A week after surgery, seven of these dogs were subjected to left CSGB by injection of ethanol. Ethanol-induced CSGB resulted in improved nerve regeneration, suggesting that the increased blood flow effectively promotes nerve regeneration in IAN defects. This canine model can contribute to further research on the long-term effects of CSGB.

Intermedin enhances sympathetic outflow via receptor-mediated cAMP/PKA signaling pathway in nucleus tractus solitarii of rats.

Direct administration of intermedin (IMD) into the brain elicits cardiovascular effects different from the systemic administration. Nucleus tractus solitarii (NTS) is an important region for the cardiovascular regulation. The present study was designed to determine the effect of IMD on modulating the sympathetic outflow and its related molecular mechanism in the NTS. Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded in anesthetized rats. Site-specific microinjection of IMD (20pmol) bilaterally into the NTS significantly increased RSNA and MAP. IMD-evoked increases of RSNA and MAP were almost abolished by pretreatment with receptor antagonist ADM22-52, an adenylyl cyclase (AC) inhibitor SQ22536, or a protein kinase A (PKA) inhibitor Rp-cAMP. However, pretreatment with another receptor antagonist calcitonin gene-related peptide (CGRP)8-37 did not suppress the increases of RSNA and MAP induced by IMD. Furthermore, IMD increased the cyclic adenosine monophosphate (cAMP) level, which was inhibited by ADM22-52 pretreatment in the NTS. These results suggest that IMD participates in the sympathetic nerve activity and central regulation of the cardiovascular system and a receptor-mediated cAMP/PKA signaling pathway is involved in IMD-induced effects in the NTS.

Macroanatomical investigation of the aorticorenal ganglion in 1-day-old infant sheep.

The aorticorenal gland belongs to the paired splanchnic ganglion, which is the main component of the coeliac plexus. It lies near the renal artery and suprarenal gland. The research was conducted on 13 1-day-old infant sheep - eight males and five females. Based on the conducted studies, it was concluded that the aorticorenal ganglion is characterized by the variable location in relation to the abdominal aorta, renal artery, caudal vena cava and suprarenal gland (holotopy), the thoracic and lumbar segment of the vertebral column (skeletotopy) (between L(1) and L(3)) and also a different shape (elongated, round, triangular, oval) as well as variable length (the aorticorenal ganglion is longer on the left side of the body; 2.72 mm) and distance from the caudal end of the suprarenal gland (longer on the left side of the body; 8.34 mm). With regard to the sex of the animal, the ganglion is the longest on the left side in ewes (3.02 mm), while in rams it is the longest on the right side (2.68 mm). Regarding the division according to sex, the longest segment was observed on the right side in ewes (9.27 mm), and the shortest segment in rams was also on the right side (6.84 mm).

The adult coeliac ganglion: a morphologic study.

The coeliac plexus is located on the sides of the coeliac trunk and nearby the origins of the superior mesenteric and renal arteries. Afferent branches get to this plexus from the vagus nerve, splanchnic nerves and the right phrenic nerve; efferents leave for viscera through periarterial plexuses and the retroportal nerves. The coeliac plexus ganglia - coeliac, superior mesenteric, aorticorenal - are prevertebral ganglia that receive the preganglionic sympathetic fibers brought by the splanchnic nerves from the thoracic spinal cord. For studying the adult coeliac ganglia dissections were performed then pieces were drawn for silver staining by the method of Bielschowsky on blocks and HE stains. The adult coeliac ganglia consist of well-defined ganglionic subunits, of a varying number of neurons with somata ranging from 14 to 48 microns and characteristically involved in extensive dendritic fields. Individual degrees of coalescence may justify the macroscopic appearance of the coeliac ganglion but its structure keeps distinctive subunits.

Considerations on the phrenic ganglia.

UNLABELLED: The phrenic ganglion is described as a small ganglion located at the junction of the right phrenic nerve and branches of the celiac plexus, on the diaphragm. The descriptions of this ganglion are few and incomplete and justify the present study which has been performed macroscopically by dissection and microscopically using silver stained (the method of Bielschowsky) drawn pieces. Dissections of 10 human adult specimens showed one or more ganglia located at the level of the terminal division of the right diaphragmatic artery; these ganglia belong to a trunk linking the right phrenic nerve and the celiac ganglion. In some specimens that nervous trunk was replaced by a ganglionated plexus. That trunk--the diaphragmatic nerve--attaches to a distinctive projection of the celiac ganglion; it may be double, but there is one ganglionated component. No left phrenic ganglia were detected. The macroscopic phrenic ganglia are distributed as follows: the lower to the adrenal gland and the upper to the diaphragm. Microscopically, the ganglia had autonomic characteristics; intrinsic microganglia were also detected within the diaphragmatic nerve. Moreover, periadventitial nervous cells were detected on the right inferior phrenic artery. IN CONCLUSION: (1) the phrenic ganglia seem to be constant structures on the right-hand side; (2) their number is variable--it may be the result of individual fragmentation or coalescence during development; (3) these ganglia may be either adrenal vasomotor or diaphragmatic vasomotor, and functionally belong to the celiac plexus; (4) intrinsic neural and periarterial locations are also possible for macroscopically undetectable populations of autonomic nervous cells.

The phrenic ganglion in man.

During educational dissections we observed a phrenic ganglion on the nerve of the phrenic artery originating from the upper pole of the right coeliac ganglion, which accompanied the right inferior phrenic artery on a female cadaver at the age of 34. In our case the left coeliac ganglion, the inferior phrenic artery, the right and left greater, lesser and least splanchnic nerves were present and normal. However, the left nerve of the phrenic artery and the phrenic ganglion were absent. We consider that this rarely reported neural formation may be of importance for anatomists and clinicians.

Blood supply of the human cervical sympathetic chain and ganglia.

OBJECTIVE: Cadaveric studies of the blood supply to the human cervical sympathetic chain and ganglia are lacking in the English literature. This study seeks to elucidate the gross blood supply of the cervical sympathetic chain so as to avoid surgical disruption of these vessels and thus decrease the risk of vascular insufficieny and subsequent dysfunction of thoracolumbar autonomic outflow to the head and neck. METHODS: Twelve (24 sides) human cadavers (8 male and 4 female) were dissected and their brachiocephalic veins, internal carotid arteries, and vertebral arteries cannulated. Red and blue latex was injected into the arteries and veins respectively. Dissection of the neck was carefully performed and the blood supply of the cervical sympathetic chain identified. RESULTS: The primary arterial supply to the sympathetic chain and ganglia were from superior to inferior the ascending pharyngeal, ascending cervical, thyrocervical trunk, and supreme intercostal arteries. The primary venous drainage of these structures was primarily by direct posterior branches into the internal jugular vein. In addition, we have found an area at the junction of the lower two-thirds and upper one-third of the neck, which is deficient in blood supply (both arterial and venous). CONCLUSIONS: Although sympathetic injury is a rare consequence of cervical operations, the current data should be useful to the surgeon who operates in the cervical region so as to avoid potential complications from disruption of the primary blood supply of the cervical sympathetic chain and ganglia. Also, future techniques of selective iatrogenic disruption of the blood supply to portions of these structures e.g. stellate ganglion may be helpful in treating entities such as hyperhydrosis.

Role of 5-HT3 receptors in activation of abdominal sympathetic C fibre afferents during ischaemia in cats.

1. Activation of abdominal sympathetic afferents during ischaemia reflexly excites the cardiovascular system. We have shown previously that exogenous 5-hydroxytryptamine (5-HT, i.e. serotonin) stimulates abdominal sympathetic afferent nerve endings, and recently have documented increased concentrations of 5-HT in intestinal lymph and portal venous plasma during brief abdominal ischaemia. The present investigation evaluated the role of endogenously produced 5-HT in activation of ischaemically sensitive abdominal sympathetic afferents. 2. Nerve activity of single-unit C fibre afferents innervating duodenum, mesentery, pancreas, portal hepatis, bile duct, gall bladder and jejunum was recorded from the right thoracic sympathetic chain of anaesthetized cats. Ischaemically sensitive C fibre afferents were identified according to their response to 5-10 min of abdominal ischaemia. 3. Intra-arterial injection of 5-HT (20 microg kg-1) increased discharge activity of twelve afferents from 0. 23 +/- 0.05 to 0.96 +/- 0.09 impulses s-1 after an onset latency of 5.7 +/- 1.4 s. Also, 2-methylserotonin (100 microg kg-1, i.a.), a 5-HT3 receptor agonist, stimulated eleven of twelve afferents to significantly increase their discharge activity from 0.25 +/- 0.05 to 0.90 +/- 0.10 impulses s-1 after a latency of 3.3 +/- 0.4 s. Furthermore, intravenous injection of tropisetron (200 microg kg-1), a 5-HT3 receptor antagonist, significantly attenuated the increase in activity of twelve other C fibre afferents during 10 min of abdominal ischaemia from 1.62 +/- 0.18 to 0.94 +/- 0.22 impulses s-1, and eliminated the response of eleven other afferents to 5-HT. 4. Both the 5-HT2 receptor agonist, alpha-methylserotonin (100 microg kg-1, i.a.), and the 5-HT1 receptor agonist, 5-carboxamidotryptamine (100 microg kg-1, i.a.), did not alter the impulse activity of these twelve afferents (0.29 +/- 0.05 to 0.31 +/- 0.06, and 0.26 +/- 0.06 to 0.29 +/- 0.06 impulses s-1, respectively). 5. Treatment with indomethacin (5 mg kg-1, i.v.) in eight different cats did not alter the response of nine C fibre afferents to exogenous 5-HT (0.91 +/- 0. 17 vs. 1.19 +/- 0.25 impulses s-1, P > 0.05). 6. The results suggest that, during mesenteric ischaemia, endogenous 5-HT contributes to the activation of abdominal sympathetic afferents, mainly through direct stimulation of 5-HT3 receptors and that the action of 5-HT on these afferents appears to be independent of the cyclo-oxygenase pathway.

Angioarchitecture of the coeliac sympathetic ganglion complex in the common tree shrew (Tupaia glis).

The angioarchitecture of the coeliac sympathetic ganglion complex (CGC) of the common tree shrew (Tupaia glis) was studied by the vascular corrosion cast technique in conjunction with scanning electron microscopy. The CGC of the tree shrew was found to be a highly vascularised organ. It normally received arterial blood supply from branches of the inferior phrenic, superior suprarenal and inferior suprarenal arteries and of the abdominal aorta. In some animals, its blood supply was also derived from branches of the middle suprarenal arteries, coeliac artery, superior mesenteric artery and lumbar arteries. These arteries penetrated the ganglion at variable points and in slightly different patterns. They gave off peripheral branches to form a subcapsular capillary plexus while their main trunks traversed deeply into the inner part before branching into the densely packed intraganglionic capillary networks. The capillaries merged to form venules before draining into collecting veins at the peripheral region of the ganglion complex. Finally, the veins coursed to the dorsal aspect of the ganglion to drain into the renal and inferior phrenic veins and the inferior vena cava. The capillaries on the coeliac ganglion complex do not possess fenestrations.

Blood flow and autoregulation in somatic and autonomic ganglia. Comparison with sciatic nerve.

We studied blood flow rates along the sciatic nerve and in the superior cervical and L-5 dorsal root ganglia of rats at rest and during reductions and increases in mean arterial pressure induced by partial exsanguination or blood transfusion. Blood flow was measured by the tissue distribution of [14C]iodoantipyrine and autoradiography. At rest, blood flow did not vary along the peripheral nerve, but was two to three times greater in dorsal root and superior cervical ganglia. In peripheral nerve, blood flow increased with increases in blood pressure. In contrast, blood flow in dorsal root and sympathetic ganglia did not vary with changes in pressure. Thus, peripheral nerve cell bodies have greater blood flow than their axons; ganglion blood flow is autoregulated within the range of blood pressure tested. Nerve ganglia appear to be protected against ischaemic stress by autoregulation rather than by a blood flow "safety margin', as in peripheral nerve.

Microvascular organization of sympathetic ganglia, with special reference to small intensely-fluorescent cells.

The vascular organization of sympathetic ganglia has been reviewed in relation to type II small intensely-fluorescent (SIF) cells. These cells are considered to be secretory cells forming large clusters surrounded by fenestrated capillaries. Immunohistochemical studies have revealed the existence of many kinds of peptides, in addition to catecholamines, in type II SIF cells. These transmitters are thought to enter the bloodstream, perfuse the adjacent ganglionic tissue, and modify the synaptic transmission and activity of sympathetic ganglionic neurons. Several authors reported portal-like intraganglionic microcirculation through which type II SIF cells participate in modulation of the principal ganglionic neurons. One large intraganglionic portal sinus located between SIF cells and principal ganglionic neurons was also reported in the inferior mesenteric ganglion. However, some authors claimed that transmitters could be absorbed through numerous capillary anastomoses, without any portal system in the superior cervical ganglion. It is noticed that the number, size, and partition of SIF-cell clusters are variable in different ganglia and different animal species. It is important to interpret the functional and morphological correlates of intraganglionic microcirculation based on the species and location of ganglia.

Differential permeability of blood microvasculatures in various sympathetic ganglia of rodents.

The ultrastructure of capillaries and their permeability to lanthanum ion and horseradish peroxidase (HRP) in various rodent sympathetic ganglia were investigated in this study. Electron microscopic observation revealed that most capillaries surrounding the principal neurons in these ganglia were of the continuous (non-fenestrated) type, while the fenestrated capillaries were consistently associated with the small granule-containing (SGC) cells in rat and hamster superior cervical ganglia and the coeliac-mesenteric ganglia (CMG) complex. Both of the capillaries surrounding the principal neurons and adjacent to SGC cells in various gerbil sympathetic ganglia or in rat and hamster thoracic ganglia were of the non-fenestrated type. After lanthanum perfusion, lanthanum tracer was limited to the blood-vessel lumen but was apparently obstructed by the tight junctions of capillaries. No lanthanum was visible in the extravascular space surrounding the principal neurons of rodent superior cervical and thoracic ganglia. By contrast, lanthanum extravasation was observed in the luminal, abluminal and perivascular surface of capillaries in the CMG complex and near SGC cells in the superior cervical ganglion. Injecting HRP showed that all blood vessels in various sympathetic ganglia were impermeable to HRP. HRP-DAB reaction product was limited to the lumen of capillaries, blocked by tight junctions and obstructed by fenestral diaphragms of fenestrated capillaries close to SGC cells. We conclude that: (1) the capillaries surrounding the principal neurons in rodent superior cervical and thoracic ganglia are more restrictive to HRP and lanthanum ion than those anywhere in the CMG complex or in regions containing SGC cells of superior cervical ganglia; (2) according to the results of lanthanum and HRP experiments, the existence of different blood-barrier properties are present among different rodent sympathetic ganglia or within the same ganglion.

Ogilvie's syndrome from disseminated varicella-zoster infection and infarcted celiac ganglia.

We report a patient who had refractory Hodgkin's disease and who received an autologous bone marrow transplantation and 8 months later developed abdominal pain associated with acute colonic dilation. The course of the patient was rapidly fatal due to a lobar pneumonia. Autopsy revealed signs of disseminated herpesvirus infection with marked hemorrhagic infarction of celiac sympathetic ganglia. This finding supports the hypothesis that denervation caused by virus reactivation and secondary hemorrhage is a main mechanism of acute colonic pseudoobstruction.

Investigation of the blood-ganglion barrier properties in rat sympathetic ganglia by using lanthanum ion and horseradish peroxidase as tracers.

Vascular permeability in various rat sympathetic ganglia, including superior cervical ganglia, thoracic ganglia and the celiac-mesenteric ganglia (CMG) complex, was investigated by using lanthanum and horseradish peroxidase (HRP) as tracers with special attention to the neuronal and small granule-containing (SGC) cell area. After lanthanum perfusion, lanthanum tracer was present within the lumen of blood vessels. No lanthanum depositions were found in the extravascular space surrounding neurons in the superior cervical and thoracic ganglia. By contrast, an accumulation of lanthanum was observed in both luminal, abluminal and subendothelial surface of blood vessels in neuronal and SGC cell areas of the CMG complex and surrounding SGC cells in superior cervical ganglia. Injecting HRP revealed that all blood vessels of various sympathetic ganglia, either in neuronal or in SGC cell areas, were impermeable to HRP. HRP reaction product was limited to the vascular lumen and macrophages. The escape of HRP was obstructed by the junctional complex at intercellular clefts of endothelia and also by the diaphragms of the fenestrated capillaries associated with SGC cells. We conclude that there are different properties in the blood-ganglion barriers among rat sympathetic ganglia: (1) continuous capillaries in superior cervical ganglia and thoracic ganglia provide an efficient blood-ganglion barrier that prevents the penetration of tracers, and (2) capillaries in the CMG complex and in regions of the superior cervical ganglia that contain SGC cells possess a selective blood-ganglion barrier that discriminates between tracers based on their molecular sizes.

Permeation of proteins from the blood into peripheral nerves and ganglia.

We have attempted to resolve apparently conflicting observations of previous investigators regarding the penetration of proteins into peripheral ganglia and nerves of the rat. Horseradish peroxidase, which is largely cleared from the blood and extracellular fluids in less than 30 min, entered all the extracellular spaces of ganglia, including the clefts between glial cells and neurons, but it did not enter the endoneurium. Rhodamine B-conjugated bovine albumin quickly entered sensory and sympathetic ganglia, but its penetration into avascular enteric nervous tissue was arrested at the outer margin of each myenteric and submucosal ganglion. If injected daily for a week, this fluorescent protein was seen also in the endoneurium, but it was still absent from enteric ganglia. The failure to enter enteric ganglia may have been due to the entrapment of aggregates of dye-labelled albumin molecules in the basal lamina that encloses the enteric nervous system. Extracellular endogenous albumin immunoreactivity was seen in all parts of peripheral nerves and in all types of ganglion. Some neuronal perikarya contained albumin-immunoreactive material; the strongest staining was in enteric neurons. Albumin may reach these cell bodies by retrograde axonal transport from peripheral terminals. We conclude that all the extracellular spaces of the rat's peripheral nervous system are accessible to plasma proteins, though diffusion occurs more slowly into the endoneurium than into ganglia.

Ganglia of the cervical part of the sympathetic trunk in the white rat. Sources of blood supply and angioarchitectonics.

Each ganglion of the cervical part of the sympathetic trunk in white rat is supplied by several arteries of diameter of 15--30 micrometers. The arteries arise from three sources: 1) large vessels adjacent to the ganglia, 2) vascular net of connective and muscular tissues surrounding the ganglion, 3) vessels of nerves and interganglionic rami. The vascular network of the cervical sympathetic ganglia was connected with the vascular plexus of the vagus nerve and cervical as well as brachial plexuses.

Microvascularization of the common tree shrew (Tupaia glis) superior cervical ganglion studied by vascular corrosion cast with scanning electron microscopy.

Microvascularization of the superior cervical ganglion (SCG) of the common tree shrew (Tupaia glis) was investigated by the vascular-corrosion-cast technique in conjunction with scanning electron microscopy. It was found that the SCG of the tree shrew is a highly vascularized organ. It receives arterial blood from branches of the external and common carotid arteries which enter the rostral and caudal portions of the ganglion. These arteries give rise to a subcapsular capillary plexus before branching off to form a group of densely packed intraganglionic capillaries. Moreover, the intraganglionic capillaries tend to follow a tortuous course that is essentially parallel to the longitudinal axis of the ganglion, and they form anastomoses with each other. In addition, the intraganglionic capillaries are also connected to a subcapsular capillary plexus. The capillaries of the SCG converge into venules and collecting veins which subsequently drain rostrally and caudally into the systemic veins. However, neither a pattern of blood vessels resembling glomeruli nor a portal-like intraganglionic microcirculation was observed.

Effect of He-Ne laser irradiation on synaptic transmission of the superior cervical sympathetic ganglion in the rat.

The effect of low-power He-Ne laser on synaptic transmission was studied in the superior cervical sympathetic ganglion of Wistar rats. Extracellular and intracellular recordings were made from isolated ganglia before and after laser irradiation. In addition, effects of ganglion irradiation on skin blood flow were observed in in vivo preparations. Irradiation on the isolated ganglion decreased the amplitude of evoked compound action potentials in the extracellular recordings. Intracellular recordings from ganglion cells revealed that the neuronal membrane was hyperpolarized, while threshold potential and latency of response were unchanged. The reduction of skin blood flow during preganglionic nerve stimulation lessened by irradiation on the ganglion. Our results indicate that low-power He-Ne laser depresses sympathetic ganglionic transmission, and hyperpolarization of ganglionic cells takes part in the mechanism of action.

Microvascularization of the rat superior cervical ganglion. A three-dimensional observation.

The three-dimensional image of the microvascularization of the rat superior cervical ganglion (SCG) was examined using the vascular corrosion cast technique in conjunction with scanning electron microscopy. It was found that the rat SCG was a highly vascularized organ. Arteries supplying the ganglion gave rise to a subcapsular capillary plexus before branching off to become intraganglionic capillaries. Two types of intraganglionic capillaries, large and small, were observed throughout the organ. Numerous anastomoses among these capillaries were found before they converged into venules and collecting veins. However, a pattern of blood vessels resembling portal-like intraganglionic microcirculation could not be demonstrated.