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.

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.

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.

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.

Denervation-induced formation of adrenergic synapses in the superior cervical sympathetic ganglion of the rat and the enhancement of this effect by postganglionic axotomy.

A study has been made at the ultrastructural level of the effects of denervation and axotomy on the synapse population of the rat superior cervical ganglion. Superior cervical ganglia were subjected unilaterally to acute (survival, 48 h) or chronic preganglionic denervation (survival, 41-189 days) by cutting the cervical sympathetic trunk; in chronic denervation experiments regeneration of preganglionic nerve fibres into the ganglion was prevented by suturing the proximal (caudal) stump of the trunk into the sternomastoid muscle. In some chronic experiments the preganglionic denervation was combined with simultaneous crush axotomy of the major postganglionic branches of the ganglion, the internal and external carotid nerves (axotomized-denervated ganglia). Control observations were made in contralateral ganglia and in ganglia from normal rats. After excision and before fixation, ganglia were incubated briefly in the presence of 5-hydroxydopamine to label adrenergic vesicles. Chronic denervation caused a statistically significant 12% decrease from control values in the cytoplasmic minor axes of the principal ganglionic neurones; axotomy combined with chronic denervation led to a 6% increase in this dimension, which was not statistically significant. The minor axes of the neuronal nuclei did not differ significantly from control values in either type of experiment. Axotomy combined with denervation led however to a 36% decrease in the incidence of nucleated neuronal profiles per unit area of ganglion. Counts of synapses were made in the various classes of ganglia and their incidence was expressed per nucleated neuronal profile, to permit comparison within and between experiments. Normal and control ganglia showed a high incidence of synapses of preganglionic cholinergic type. Nerve terminal profiles and synapses containing small dense-cored vesicles, as distinct from the efferent synapses of small granule-containing cells, were not found to be present on the principal neurones or their dendrites in these ganglia, despite strong 5-hydroxydopamine labelling of small dense-cored vesicles within cell bodies and dendrites. After acute denervation extremely few residual synapses were found in the ganglion, in areas remote from small granule-containing cells, and these residual synapses were of the cholinergic type. Acute denervation led to the appearance of vacated or isolated postsynaptic densities; such densities were also found, but were fewer in number, in chronically denervated and axotomized-denervated ganglia.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

Extent of survival and vascularization of adult superior cervical sympathetic or nodose ganglia transplanted into the septal nuclei or choroid fissure of adult rats.

Adult superior cervical sympathetic ganglia were auto-transplanted, and adult nodose ganglia were homografted into the septal nuclei or the choroid fissure of adult Wistar rats. At times from 4 h to 9 weeks after operation, the distribution of surviving transplanted neurons was compared with the development of the transplant vascularization, as visualized by transcardial Indian ink filling of the host vascular system. Within 24 h, the ganglionic neurons and Schwann cells of the interior of the transplants in both sites were necrotic. The surviving neurons and Schwann cells formed a shell, occupying those areas of the transplant periphery which were in direct contact with the host circulation. Occasional ink-filled vessels were evident at this time in transplants in the choroid fissure, but there were none in the septal nuclei, where vessels did not appear until the next day. Blood vessels reached the centre of the ganglia by 3-4 days in the choroid fissure and one week in the septal nuclei, the finest diameter capillaries forming last. At longer survivals there was a slow loss of neurons, notable between 1 and 2 months, and leading progressively (especially in the septal transplantation site) to the disappearance of all but a very small number of ganglionic neurons. The general findings were similar for both types of ganglion, and in both sites, but the initial cell loss was much greater for both types of ganglia in the septum (over 90%) as compared with about a 50% loss in the choroid fissure. The initial rapid cell loss was probably a result of ischaemia. The subsequent, slow progressive loss may be associated with failure to make or receive neuronal connections, or the absence of appropriate growth factors.

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.

Increased density of perivascular nerves to the major cerebral vessels of the spontaneously hypertensive rat: differential changes in noradrenaline and neuropeptide Y during development.

Fluorescence and immunohistochemical techniques were used to study the pattern and density of perivascular nerves containing noradrenaline (NA) and neuropeptide Y (NPY) supplying the major cerebral arteries of 4-, 6-, 8- and 12-week-old spontaneously hypertensive rats (SHR) and normotensive Wistar (WIS) controls. Levels of NA and NPY in the superior cervical ganglia were measured. The density of nerves containing NA and NPY was greater in the hypertensive animals at all ages studied. However, the developmental changes in the density of innervation showed similar trends in both SHR and WIS groups. With few exceptions, there was a significant increase in the density of nerves containing NA from 4 to 6 weeks and from 8 to 12 weeks of age. This was in contrast to a low expression, and in some vessels a significant decrease in the number of NPY-containing nerves from 4 to 6 weeks. The density of nerve fibres containing NPY increased significantly in almost all vessels between 6 and 8 weeks of age and then stabilized. Thus there is a differential time course for the appearance of NA and NPY during development. Furthermore, the hyperinnervation of cerebral vessels in SHR by nerves containing NA and NPY precedes the onset of hypertension and associated medial hypertrophy. High-performance liquid chromatography and enzyme-linked immunosorbant assays show that the NA and NPY contents of the superior cervical ganglion do not reflect the changes in innervation pattern seen in the terminal fibres in the cerebral arteries. This tends to support the view that a local neurovascular mechanism is involved in the maintenance of hypertension. The possibility that increase in NPY as well as NA in cerebral perivascular nerves of hypertensive animals is involved in the protection of the blood-brain barrier against oedema and cerebral haemorrhage is raised.

Local blood flow and vascular permeability of autonomic ganglion-transplants in the brain.

The purpose of this study was to determine whether the blood vessels of transplanted neural tissue retain their functional characteristics. Quantitative autoradiography was used to measure local blood flow (F) with iodoantipyrine and the blood-to-tissue transfer constant (K) with alpha-aminoisobutyric acid in superior cervical ganglion (SCG) allografted to the surface of ventricle IV and into the cerebellum of the same rat. The F of the intraparenchymal grafts was slightly lower than that of the intraventricular grafts; F decreased between 1 and 4 weeks in SCG grafts at both sites. The permeability-surface area (PS) product of the microvessels and extraction fraction of AIB were calculated from these results and indicated restricted transvascular passage of the amino acid in both the in situ and grafted SCG. Surface area (S) and average length (L) of the microvessels were determined morphometrically and their permeability (P) was calculated from these data. Although K and PS decreased in the grafts compared to in situ SCG, a comparable decrease in S indicated that P was similar for the microvessels of both in situ and 1-week-old SCG transplants: 3.5-4.3 x 10(-6) cm/s. Between 1 and 4 weeks after transplantation, the P of the microvessels decreased to approximately 1.6-2.3 x 10(-6) cm/s without any change in S. Thus, the blood vessels of SCG grafts within or upon the brain initially retain the functional attributes of in situ SCG microvessels, but the average permeability of the graft microvessels decreases to approximately one half of the initial value by 4 weeks after transplantation.

The nerves to blood vessels supplying blood to nerves: the innervation of vasa nervorum.

Noradrenergic, serotoninergic and peptidergic nerves have been demonstrated in perivascular plexuses of vasa nervorum of sympathetic, parasympathetic and somatic nerve trunks. 5-Hydroxytryptamine-, vasoactive intestinal polypeptide- and substance P-containing fibers were found by immunohistochemistry to variable extents in whole mounts of the epineurium of sciatic, vagus and paravertebral sympathetic chains of rabbits. Innervation increased with age. This suggests an hitherto unsuspected role for these vasoactive substances in normal blood flow to nerves and in the genesis of experimental and human neuropathies.

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.

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.

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.

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).

Evidence for a blood-ganglion barrier in the superior cervical ganglion of the rat.

The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). By light microscopy, peroxidase activity was found in three locations: in the capsule of the ganglion, in the lumina of the blood vessels, and within macrophages. Electron microscopy revealed that virtually all ganglionic blood vessels contained HRP 5 minutes following its administration. The intensity of peroxidase activity declined over the period of 15 minutes. The enzyme was localized on the luminal surface of the endothelial cells, attaching to the glycocalyx. Endothelial microvilli, projecting into the vessel lumen, were also covered with peroxidase. Micropinocytotic vesicles on the luminal surface of the endothelium contained reaction product. Some of these vesicles were free within the cytoplasm of the endothelium but none was observed on the abluminal surface. Peroxidase activity was not detected in the extracellular space even after 15 minutes. The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions; features associated with the blood-brain barrier of the central nervous system and peripheral nerves. It is proposed that these vessels perform a barrier function between the capillary circulation and the superior cervical ganglion.

Development of blood vessels in the sympathetic trunk ganglia of the chick embryo during their histomorphogenesis.

The development of the vascular patterns and the differentiation of the cellular components have been studied in the ganglia of the sympathetic trunk in chicken embryos from the 3rd to the 16th day of incubation. The time and the mode of formation of the extrinsic and intrinsic vascular networks seem to conform to the pattern of growth and differentiation of the nerve cells and to their distribution within the sympathetic ganglia.