RNA Sequencing Reveals Novel Transcripts from Sympathetic Stellate Ganglia During Cardiac Sympathetic Hyperactivity

Cardiovascular disease is the most prevalent age-related illness worldwide, causing approximately 15 million deaths every year. Hypertension is central in determining cardiovascular risk and is a strong predictive indicator of morbidity and mortality; however, there remains an unmet clinical need for disease-modifying and prophylactic interventions. Enhanced sympathetic activity is a well-established contributor to the pathophysiology of hypertension, however the cellular and molecular changes that increase sympathetic neurotransmission are not known. The aim of this study was to identify key changes in the transcriptome in normotensive and spontaneously hypertensive rats. We validated 15 of our top-scoring genes using qRT-PCR, and network and enrichment analyses suggest that glutamatergic signalling plays a key role in modulating Ca2+ balance within these ganglia. Additionally, phosphodiesterase activity was found to be altered in stellates obtained from the hypertensive rat, suggesting that impaired cyclic nucleotide signalling may contribute to disturbed Ca2+ homeostasis and sympathetic hyperactivity in hypertension. We have also confirmed the presence of these transcripts in human donor stellate samples, suggesting that key genes coupled to neurotransmission are conserved. The data described here may provide novel targets for future interventions aimed at treating sympathetic hyperactivity associated with cardiovascular disease and other dysautonomias.

Chronic lead exposure enhances the sympathoexcitatory response associated with P2X4 receptor in rat stellate ganglia

Chronic lead exposure causes peripheral sympathetic nerve stimulation, including increased blood pressure and heart rate. Purinergic receptors are involved in the sympathoexcitatory response induced by myocardial ischemia injury. However, whether P2X4 receptor participates in sympathoexcitatory response induced by chronic lead exposure and the possible mechanisms are still unknown. The aim of this study was to explore the change of the sympathoexcitatory response induced by chronic lead exposure via the P2X4 receptor in the stellate ganglion (SG). Rats were given lead acetate through drinking water freely at doses of 0 g/L (control group), 0.5 g/L (low lead group), and 2 g/L (high lead group) for 1 year. Our results demonstrated that lead exposure caused autonomic nervous dysfunction, including blood pressure and heart rate increased and heart rate variability (HRV) decreased. Western blotting results indicated that after lead exposure, the protein expression levels in the SG of P2X4 receptor, IL-1β and Cx43 were up-regulated, the phosphorylation of p38 mitogen-activated protein kinase (MAPK) was activated. Real-time PCR results showed that the mRNA expression of P2X4 receptor in the SG was higher in lead exposure group than that in the control group. Double-labeled immunofluorescence results showed that P2X4 receptor was co-expressed with glutamine synthetase (GS), the marker of satellite glial cells (SGCs). These changes were positively correlated with the dose of lead exposure. The up-regulated expression of P2X4 receptor in SGCs of the SG maybe enhance the sympathoexcitatory response induced by chronic lead exposure.

Effects of local cardiac denervation on cardiac innervation and ventricular arrhythmia after chronic myocardial infarction

Background

Modulation of the autonomic nervous system (ANS) has already been demonstrated to display antiarrhythmic effects in patients and animals with MI. In this study, we investigated whether local cardiac denervation has any beneficial effects on ventricular electrical stability and cardiac function in the chronic phase of MI.

Methods

Twenty-one anesthetized dogs were randomly assigned into the sham-operated, MI and MI-ablation groups, respectively. Four weeks after local cardiac denervation, LSG stimulation was used to induce VPCs and VAs. The ventricular fibrillation threshold (VFT) and the incidence of inducible VPCs were measured with electrophysiological protocol. Cardiac innervation was determined with immunohistochemical staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). The global cardiac and regional ventricular function was evaluated with doppler echocardiography in this study.

Results

Four weeks after operation, the incidence of inducible VPC and VF in MI-ablation group were significantly reduced compared to the MI dogs (p<0.05). Moreover, local cardiac denervation significantly improved VFT in the infarcted border zone (p<0.05). The densities of GAP43 and TH-positive nerve fibers in the infarcted border zone in the MI-ablation group were lower than those in the MI group (p<0.05). However, the local cardiac denervation did not significantly improve cardiac function in the chronic phase of MI, determined by the left ventricle diameter (LV), left atrial diameter (LA), ejection fraction (EF).

Conclusions

Summarily, in the chronic phase of MI, local cardiac denervation reduces the ventricular electrical instability, and attenuates spatial heterogeneity of sympathetic nerve reconstruction. Our study suggests that this methodology might decrease malignant ventricular arrhythmia in chronic MI, and has a great potential for clinical application.

Inflammatory and apoptotic remodeling in autonomic nervous system following myocardial infarction

Background

Chronic myocardial infarction (MI) triggers pathological remodeling in the heart and cardiac nervous system. Abnormal function of the autonomic nervous system (ANS), including stellate ganglia (SG) and dorsal root ganglia (DRG) contribute to increased sympathoexcitation, cardiac dysfunction and arrythmogenesis. ANS modulation is a therapeutic target for arrhythmia associated with cardiac injury. However, the molecular mechanism involved in the pathological remodeling in ANS following cardiac injury remains to be established.

Methods and results

In this study, we performed transcriptome analysis by RNA-sequencing in thoracic SG and (T1-T4) DRG obtained from Yorkshire pigs following either acute (3 to 5 hours) or chronic (8 weeks) myocardial infarction. By differential expression and weighted gene co-expression network analysis (WGCNA), we identified significant transcriptome changes and specific gene modules in the ANS tissues in response to myocardial infarction at either acute or chronic phases. Both differential expressed genes and the member genes of the WGCNA gene module associated with post-infarct condition were significantly enriched for inflammatory signaling and apoptotic cell death. Targeted validation analysis supported a significant induction of inflammatory and apoptotic signal in both SG and DRG following myocardial infarction, along with cellular evidence of apoptosis induction based on TUNEL analysis. Importantly, these molecular changes were observed specifically in the thoracic segments but not in their counterparts obtained from lumbar sections.

Conclusion

Myocardial injury leads to time-dependent global changes in gene expression in the innervating ANS. Induction of inflammatory gene expression and loss of neuron cell viability in SG and DRG are potential novel mechanisms contributing to abnormal ANS function which can promote cardiac arrhythmia and pathological remodeling in myocardium.

Sympathetic nerve fibers and ganglia in canine cervical vagus nerves: localization and quantitation

BACKGROUND

Cervical vagal nerve (CVN) stimulation may improve left ventricular ejection fraction in patients with heart failure.

OBJECTIVES

To test the hypothesis that sympathetic structures are present in the CVN and to describe the location and quantitate these sympathetic components of the CVN.

METHODS

We performed immunohistochemical studies of the CVN from 11 normal dogs and simultaneously recorded stellate ganglion nerve activity, left thoracic vagal nerve activity, and subcutaneous electrocardiogram in 2 additional dogs.

RESULTS

A total of 28 individual nerve bundles were present in the CVNs of the first 11 dogs, with an average of 1.87±1.06 per dog. All CVNs contain tyrosine hydroxylase-positive (sympathetic) nerves, with a total cross-sectional area of 0.97±0.38 mm(2). The sympathetic nerves were nonmyelinated, typically located at the periphery of the nerve bundles and occupied 0.03%-2.80% of the CVN cross-sectional area. Cholineacetyltransferase-positive nerve fibers occupied 12.90%-42.86% of the CVN cross-sectional areas. Ten of 11 CVNs showed tyrosine hydroxylase and cholineacetyltransferase colocalization. In 2 dogs with nerve recordings, we documented heart rate acceleration during spontaneous vagal nerve activity in the absence of stellate ganglion nerve activity.

CONCLUSIONS

Sympathetic nerve fibers are invariably present in the CVNs of normal dogs and occupy in average up to 2.8% of the cross-sectional area. Because sympathetic nerve fibers are present in the periphery of the CVNs, they may be susceptible to activation by electrical stimulation. Spontaneous activation of the sympathetic component of the vagal nerve may accelerate the heart rate.

Effect of chronic forced running on gene expression of catecholamine biosynthetic enzymes in stellate ganglia of rats

The sympathoneural system has a profound influence on the heart function. Sympathetic neurons are the major contributors to the huge rise of circulating noradrenaline (NA) level in response to stressful stimuli. Treadmill training in rats is forced exercise which has the propensity to induce both psychological and physical stress. The aim of this study is to examine how chronic forced running (CFR) affects the expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT)) and cAMP response element-binding (CREB) in stellate ganglia, as well as the concentrations of catecholamines, adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in the plasma of rats. Also, we investigated how the additional acute immobilization stress changes the mentioned parameters. The rat training program consisted of 12 weeks running on a treadmill (20 m/min, 20 min/day). We found that CFR increases TH and DBH mRNA and protein levels in stellate ganglia, which is followed by increased NA concentration in the plasma. CFR reduces the level of PNMT mRNA, while the level of PNMT protein remains unchanged in stellate ganglia. The increased expression of TH and DBH genes positively correlates with the expression of CREB in stellate ganglia and with plasma ACTH level, while reduced level of PNMT mRNA in stellate ganglia correlates with reduced plasma CORT level. The additional acute immobilization stress increased gene expression of catecholamine biosynthetic enzymes in stellate ganglia, as well as catecholamines, ACTH and CORT levels in the plasma. The results presented here suggest that the continuous increase of the noradrenaline biosynthetic enzyme expression in stellate ganglia due to CFR may play a role in growing risk of cardiovascular diseases.

Acute myocardial infarction induces bilateral stellate ganglia neural remodeling in rabbits

INTRODUCTION

Myocardial infarction (MI) results in cardiac nerve sprouting in the myocardium. Whether or not similar neural remodeling occurs in the stellate ganglia (SGs) is unknown. We aimed to test the hypothesis that MI induces bilateral SG nerve sprouting.

METHODS

Acute MI was created by coronary artery ligation in rabbits (n=12). Serum nerve growth factor (NGF) level was measured by enzyme-linked immunosorbent assay. The hearts and bilateral SGs were harvested for immunohistochemistry after 1 week in six rabbits and after 1 month in six rabbits. Immunostaining for tyrosine hydroxylase (TH), growth-associated protein 43 (GAP43), choline acetyltransferase (ChAT), and synaptophysin (SYN) was performed to determine the magnitude of nerve sprouting. Tissues from six normal rabbits were used as controls. Nerve density was determined by computerized morphometry.

RESULTS

Myocardial infarction results in increased serum NGF levels at 1 week (1519.8±632.2 ng/ml) that persist up to 1 month (1361.2±176.3 ng/ml) as compared to controls (89.6±34.9 ng/ml) (P=.0002 and P=.0001, respectively). Immunostaining demonstrated nerve sprouting and hyperinnervation in both SGs after MI. The nerve densities (μm(2)/ganglion cell) in SG 1 week after MI and 1 month after MI and those in control groups, respectively, were as follows: GAP43: 278±96, 225±39, and 149±57 (P=.01); SYN: 244±152, 268±115, and 102±60 (P=.02); TH: 233±71, 180±50, and 135±68 (P=.047); ChAT: 244±100, 208±46, and 130±41 μm(2)/cell (P=.01).

CONCLUSIONS

Myocardial infarction increases serum NGF levels and induces nerve sprouting and hyperinnervation in bilateral SGs for at least 1 month after MI. The hyperinnervation includes both adrenergic axons and cholinergic axons in the SG.

Prions in the peripheral nerves of bovine spongiform encephalopathy-affected cattle

With the use of increasingly sensitive methods for detection of the abnormal isoform of prion protein (PrPSc) and infectivity in prion diseases, it has recently been shown that parts of the peripheral nervous system (PNS) of bovine spongiform encephalopathy (BSE)-affected cattle may become infected. It has been reported that prions spread to the central nervous system (CNS) via the PNS in sheep scrapie, but the pathogenesis of BSE in cattle is less well understood. To determine whether parts of the PNS other than those implicated directly in the hypothetical pathogenetic spread of agent from the intestine to the CNS become involved before or after the CNS is affected, PrPSc distribution was investigated by a highly sensitive Western blotting technique in dorsal root ganglia, stellate ganglion, phrenic, radial and sciatic nerves, adrenal gland and CNS of cattle that were inoculated orally with BSE-affected brain and culled sequentially. In experimentally BSE-affected cattle, PrPSc was first detected in the CNS and dorsal root ganglia; subsequently, PrPSc accumulation was detected in the peripheral nerve trunks. PrPSc was also detected in the adrenal glands of cattle that showed clinical signs. No PrPSc was detected in the PNS of BSE-negative cattle. This study shows that, with respect to dorsal root ganglia, a paravertebral sympathetic ganglion and the somatic nerves examined, PrPSc is detected in the PNS during the disease course at the same time as, or after, it accumulates in the CNS.

Intractable cryptogenic frontal lobe epilepsy in a patient with MURCS association

The MURCS association is a rare, nonrandom association of müllerian duct aplasia, renal aplasia and cervicothoracic somite dysplasia. The etiology is unknown. Although it is usually a sporadic disorder, familial cases with uterovaginal anomalies have been reported. Occasionally, it may be accompanied by abnormalities involving various other organs or systems. Malformations related to the central nervous system are very rare and the presence of seizures has not been reported previously. We present a 26-year-old female with MURCS association who had late onset, drug resistant partial seizures presumably originating in the frontal lobe.

Circadian variations of stellate ganglion nerve activity in ambulatory dogs

BACKGROUND

The presence of circadian variations in sympathetic outflow from the stellate ganglia is unclear.

OBJECTIVES

The purpose of this study was to continuously record stellate ganglion nerve activity (SGNA) in ambulatory dogs.

METHODS

We performed continuous 24-hour left (N = 3) or bilateral (N = 3) SGNA recordings in normal ambulatory dogs using implanted Data Sciences International transmitters. We also performed simultaneous ECG recording (n = 5) or simultaneous ECG and blood pressure recordings (n = 1).

RESULTS

The total duration of continuous ambulatory recording averaged 41.5 +/- 16.6 days. Five dogs had persistent stable recording, and one dog developed hardware malfunction in week 3. SGNA was followed immediately (<1 second) by heart rate and blood pressure elevation and a reduced standard deviation of consecutive activation cycle length (SDNN) from 236 +/- 93 ms to 121 +/- 51 ms (P = 0.007). Heart rate correlated significantly with SGNA. When there was a sudden increase of SGNA, the sudden increase occurred bilaterally in 90% of the episodes. Both heart rate and SGNA showed statistically significant (P <.01) circadian variation. Nadolol (20 mg/day for 5 days) reduced average heart rate from 99 +/- 8 bpm at baseline to 88 +/- 9 bpm (N = 6, P = .001) but did not significantly alter SGNA. Immunohistochemical staining of the stellate ganglia showed tyrosine hydroxylase-positive ganglion cells and nerves at the recording site.

CONCLUSION

There is a circadian variation in sympathetic outflow from canine stellate ganglia. Circadian variation of SGNA is an important cause of circadian variations of cardiac sympathetic tone.

A novel technique for experimental stellate ganglion block in rats

A stellate ganglion block (SGB) is routinely performed in a clinical setting for the treatment of sympathetically maintained pain syndromes. However, the cardiovascular effects of SGB have not been well defined. The purpose of the present study was to develop a new technique of SGB in a rat model. Our new technique of SGB is a posterior percutaneous approach and uses the cartilaginous process of the C7 spinous process as a landmark. Twenty-six Sprague-Dawley female rats were divided into six groups. Group I (n = 4) underwent right sided SGB, Group II (n = 5) underwent left-sided SGB, and Group III (n = 5) underwent bilateral SGB using bupivacaine 0.25%. Three additional sham groups (n = 4 in each group) served as controls to each of the three treatment groups. Ipsilateral eyelid droop (ptosis) was observed in all animals that underwent SGB with bupivacaine. Heart rate decreased significantly for up to 45 min after bilateral SGB compared with control groups. However, this value did not change in rats after unilateral SGB. In 9 additional rats, we evaluated the accuracy of SGB by injecting methylene blue to stain the right (n = 3), left (n = 3), and bilateral SGB (n = 3). At autopsy, 11 of 12 SG were stained post-methylene blue injection. We conclude from our study that our new approach, posterior percutaneous SGB is a reliable technique that can be used for further studies.

IMPLICATIONS

We describe a new technique for stellate ganglion block in rats that may be used in future studies to investigate the role of cervical sympathetic nervous system (especially the stellate ganglion) in regulating sympathetically maintained pain and myocardial function.

The anatomical rationale for an upper limb sympathetic blockade: preliminary report

Stellate ganglion blockade (SGB) has long been considered pivotal in the diagnosis, determination of prognosis and management of chronic regional pain syndrome (CRPS) by sympathectomy. To date a variety of SGB techniques have been described. An inaccurate SGB may mislead clinicians and deny patients a potentially beneficial procedure. In order to obtain a predictable and readily reproducible blockade of the upper limb, a modified anterior technique was evaluated. This modified sympathetic block was performed in 10 adult cadavers (n=19 sides). Toluidine blue solution (10 ml) was injected and, following median sternotomy, the extent of spread of dye was evaluated. In one cadaver a dual block using both the modified and the standard techniques was performed. Proximal spread to the seventh cervical vertebra was noted in all blocks; distal spread extended to the neck of the third rib (n=3), neck of the fourth rib 7 (n=15) and neck of the seventh rib (n=1). Medial spread was greater than lateral spread and extended to the vertebral bodies (vagus nerve was also stained) while lateral spread in all cases "blocked" lower roots of the brachial plexus and was consistently noted beyond the usual location of the nerve of Kuntz. This modified technique demonstrated that the lower cervical ganglia and proximal thoracic sympathetic trunk were consistently stained. It should be noted that the spread was sufficiently lateral to block the nerve of Kuntz. The pitfalls of this technique aside, we suggest that this technique be reserved for therapeutic purposes, particularly when sympathectomy is not possible.

Effect of β-Adrenoceptor Blockade on Cardiac Activity in Rats during Postnatal Ontogeny

Electrical stimulation of the right stellate ganglion produces a positive chronotropic effect in 21-, 56-, and 100-day-old rats. The response of the heart rate to suprathreshold stimulation increased from the 21st to 100th day. By contrast, during beta-adrenoceptor blockade the heart rate response decreased. The data suggest that the role of beta-adrenoceptor in the regulation of cardiac chronotropic function increased with age.

A model of myocarditis

Myocarditis was induced by synergic interactions of serotonin- and cholinergic nerve fibers during potentiation of vagal inhibition of cardiac activity by stimulation of the stellate ganglion. Thus modeled myocarditis was associated with increased content of serotonin and decreased concentrations of acetylcholine and catecholamines in the myocardial tissue. Blockade of 5HT3(S3) receptors in autonomic ganglia and 5HT1,2(S1,2) receptors in the myocardium improved myocardial contractility and reduced the severity of myocarditis.

[Enzyme and chemical characteristics of neurocytes of cervicothoracic ganglion of deafferented albino rats]

The influence of chemical deafferentation (capsaicin 50 mg/kg in dose) on age-related reorganisations of cervicothoracic ganglion neurocytes was studied. Disturbance of normal age dynamics of neurocyte area, change of neurocyte choline esterase and monoaminooxidase activity and ganglionic choroid plexus density within 6 months following neonatal administration of capsaicine were discovered. The changes were maximally manifested on d 30. Metric and histochemical parameters did not stabilise completely within observation terms.

Expression of vasoactive intestinal polypeptide and calcitonin gene-related peptide in human stellate ganglia after acute myocardial infarction

Using the method of indirect immunofluorescence the distribution of vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) was investigated in autopsy specimens of human stellate ganglia following acute myocardial infarction (AMI). The dramatic increase of both VIP- and CGRP-immunoreactivities in principal ganglionic neurons as well as of calcitonin gene-related peptide in perineuronal nets was revealed. It was concluded that hypoxia and myocardial ischaemia following AMI are the main inducing factors for activation of both vasoactive regulatory neuropeptide synthesis. The upregulation of VIP and CGRP expression in sympathetic ganglionic neurons may provide regulatory and trophic support to the ischaemic heart.

Distribution of vasoactive intestinal polypeptide-, calcitonin gene-related peptide-, somatostatin- and neurofilament-immunoreactivities in sympathetic ganglia of human fetuses and premature neonates

The distribution patterns of vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), somatostatin (SOM) and neurofilament (NF) immunoreactivities (IR) were studied in the stellate ganglia of human fetuses and neonates at 24-26 weeks gestation. Sizeable populations with some quantitative variations of VIP-, CGRP- and SOM immunoreactive nerve cells were detected in all ganglia studied. In marked contrast, neurofilament expression was down-regulated. The upregulation of VIP, CGRP and SOM expression suggested their inductor effect on growth and differentiation neurons as well as on the development of their neurotransmitter properties. The main neuropeptides-inducing factor of sympathetic ganglia in human prenatal ontogenesis may be considered as a relative hypoxia.

Upregulation of vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) expression in stellate ganglia of children with congenital cardiovascular lesions

The distribution patterns of vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) immunoreactivities (IR) in stellate ganglia of human neonates and infants with congenital heart and vascular lesions were investigated by the method of indirect immunohistochemistry. The results demonstrated upregulation of VIP and CGRP expression in principal ganglionic neurons independently of the type of lesion. It is suggested that the activation of neuropeptide synthesis in stellate ganglia is a compensatory reaction of ganglionic neurons in response to congenital cardiovascular lesions, in regulation of heart contractility, and as a trophic influence on the ischemic myocardium. Hypoxia is the main inducing factor for the upregulation of VIP and CGRP expression in sympathetic neurons.

Lack of neurotrophin-4 causes selective structural and chemical deficits in sympathetic ganglia and their preganglionic innervation

Neurotrophin-4 (NT-4) is perhaps the still most enigmatic member of the neurotrophin family. We show here that NT-4 is expressed in neurons of paravertebral and prevertebral sympathetic ganglia, i.e., the superior cervical (SCG), stellate (SG), and celiac (CG) ganglion. Mice deficient for NT-4 showed a significant reduction (20-30%) of preganglionic sympathetic neurons in the intermediolateral column (IML) of the thoracic spinal cord. In contrast, neuron numbers in the SCG, SG, and CG were unchanged. Numbers of axons in the thoracic sympathetic trunk (TST) connecting the SG with lower paravertebral ganglia were also reduced, whereas axon numbers in the cervical sympathetic trunk (CST) were unaltered. Axon losses in the TST were paralleled by losses of synaptic terminals on SG neurons visualized by electron microscopy. Furthermore, immunoreactivity for the synaptic vesicle antigen SV2 was clearly reduced in the SG and CG. Levels of catecholamines and tyrosine hydroxylase immunoreactivity were dramatically reduced in the SG and the CG but not in the SCG. Despite this severe phenotype in the sympathetic system, blood pressure levels were not reduced and displayed a pattern more typical of deficits in baroreceptor afferents. Numbers of IML neurons were unaltered at postnatal day 4, suggesting a postnatal requirement for their maintenance. In light of these and previous data, we hypothesize that NT-4 provided by postganglionic sympathetic neurons is required for establishing and/or maintaining synapses of IML neurons on postganglionic cells. Impairment of synaptic connectivity may consequently reduce impulse flow, causing a reduction in transmitter synthesis in postganglionic neurons.

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.

Nerve sprouting and sudden cardiac death

The factors that contribute to the occurrence of sudden cardiac death (SCD) in patients with chronic myocardial infarction (MI) are not entirely clear. The present study tests the hypothesis that augmented sympathetic nerve regeneration (nerve sprouting) increases the probability of ventricular tachycardia (VT), ventricular fibrillation (VF), and SCD in chronic MI. In dogs with MI and complete atrioventricular (AV) block, we induced cardiac sympathetic nerve sprouting by infusing nerve growth factor (NGF) to the left stellate ganglion (experimental group, n=9). Another 6 dogs with MI and complete AV block but without NGF infusion served as controls (n=6). Immunocytochemical staining revealed a greater magnitude of sympathetic nerve sprouting in the experimental group than in the control group. After MI, all dogs showed spontaneous VT that persisted for 5.8+/-2.0 days (phase 1 VT). Spontaneous VT reappeared 13.1+/-6.0 days after surgery (phase 2 VT). The frequency of phase 2 VT was 10-fold higher in the experimental group (2.0+/-2.0/d) than in the control group (0.2+/-0.2/d, P<0.05). Four dogs in the experimental group but none in the control group died suddenly of spontaneous VF. We conclude that MI results in sympathetic nerve sprouting. NGF infusion to the left stellate ganglion in dogs with chronic MI and AV block augments sympathetic nerve sprouting and creates a high-yield model of spontaneous VT, VF, and SCD. The magnitude of sympathetic nerve sprouting may be an important determinant of SCD in chronic MI.

Signs of sympathetic denervation associated with a thoracic melanoma in a horse

Sympathetic denervation in a 20-year-old, gray, Thoroughbred-Percheron gelding was manifested by cutaneous hyperthermia and sweating over the right side of the body, demarcated by a line from the withers to the elbow and extending cranially. There was cutaneous hyperthermia over the right side of the head, but other signs of Horner's syndrome (sweating, ptosis, miosis, enophthalmos) were not present. The pattern of cutaneous hyperthermia and sweating was consistent with sympathetic denervation localized to the cervicothoracic ganglion, and thoracic radiographs revealed increased density in the craniodorsal thorax. Cytologic evaluation of a sample of pleural effusion revealed mesothelial cells containing melanin and cells suggestive of melanocytes or melanoblasts. Treatment with oral cimetidine and intrapleural cisplatin was not successful. A necropsy was not performed, but the clinical findings supported a diagnosis of thoracic melanoma involving the cervicothoracic ganglion.

[Age-related changes in the autonomic ganglia]

Ultrastructure of vegetative ganglions (neck-thoracic, intracardial and intestinal) of Wistar and SHR rats, 26-28 months of age was studied electron-microscopically. The most pronounced changes were found in the neck-thoracic ganglions where, apart from lipofuscin deposits, lamellar bodies were frequently found. Redistribution of neuromediators in the neuron body and an increase of the neuroactive substances release into the intercellular space of the ganglion occur with age. The data on possible postsynaptic influence on the presynapse by means of neuromediators are presented. Nissl bodies hypertrophy was observed in the neck-thoracic and intracardial ganglions of old SHR rats.

The importance of thrombus organization and stellate cell phenotype in collagen I gene expression in human, coronary atherosclerotic and restenotic lesions

OBJECTIVES

Collagen synthesis is one of the major mechanisms of primary atherosclerotic plaque growth and is likely to be similarly important in restenosis. The patterns of collagen gene expression in human restenosis and associations with thrombosis/hemorrhage have not been described.

METHODS

Using human coronary artery samples obtained via the atherectomy catheter, we compared primary plaques (40 specimens) and restenotic lesions (41 specimens) for type I collagen gene expression using immunocytochemistry (SPI.D8 antibody to type I procollagen, an intracellular precursor of mature collagen) with subsequent computer image analysis.

RESULTS

Scattered positive cells were identified in specific, non-random patterns. According to logistic regression analyses, type I procollagen gene expression seems to be more closely associated with certain morphological features (organized thrombus, microvessels, regions enriched with stellate cells) than with belonging to a primary vs. a restenotic sample. However, there may be a tendency for restenotic tissue to have slightly higher numbers of type I procollagen-positive cells than primary lesion tissue.

CONCLUSIONS

Symptomatic primary and restenotic lesions exhibit similar patterns of type I collagen gene expression. Plaque microvessels and thrombi/hemorrhages (common features of both kinds of advanced lesions) might stimulate collagen synthesis equally well irrelevant to the nature of the lesion.

Noradrenergic hyperinnervation in the heart of stroke-prone spontaneously hypertensive rats (SHRSP)

Noradrenergic (NA) nerve fiber density was investigated in the subepicardium and myocardium of ventricles in stroke-prone spontaneously hypertensive rats (SHRSP) and was compared with that of normotensive Wistar Kyoto (WKY) rats. Fluorescent NA nerve fibers in the subepicardium of the right and left ventricles of both strains at the ages of 10, 30, 60, 90, and 180 days were examined by the glyoxylic acid method. NA nerve fibers in the myocardium of the right and left ventricles and the ventricular septum of both strains at the ages of 30, 90, and 180 days were also examined in a similar manner. The density of NA nerve fibers was measured by quantitative image analysis. The distribution pattern of NA nerve fibers in the entire subepicardium of ventricles of both strains showed a meshwork pattern throughout the examination period. In sections of the myocardium, NA nerve fibers were distributed between heart muscle cells and around blood vessels in both strains at all ages examined. The densities of NA nerve fibers in the subepicardium of the ventricles of SHRSP were significantly higher than those of WKY rats at all ages examined except for the subepicardium of the left ventricle at 90 days of age. The densities in the myocardium of the right ventricle in 30- and 90-day-old SHRSP were significantly higher than those in WKY rats. The ratios of NA nerve fiber density of SHRSP to that of WKY rats were greater in the subepicardium of the right and left ventricles, except at 90 days of age, and in the myocardium of the right ventricle of younger animals as compared with older ones. NA hyperinnervation in the subepicardium and myocardium of the ventricles of SHRSP may be a primary change of the heart before the onset of hypertension and may be caused by hyperfunction of the stellate ganglia.

Pathologic alterations in pre- and postsynaptic elements in aged mouse sympathetic ganglia

Dysfunction of the sympathetic autonomic nervous system is an increasingly recognized, although poorly understood, complication of increasing age in experimental animals and man. In this study of young adult (4-6 months old) and aged (12-24 months old) mice we have examined the ultrastructural appearance of perikarya, dendritic processes, preterminal axons, and synapses in selected sympathetic ganglia as well as the three-dimensional structure of the dendritic arborizations of principal sympathetic neurons using intracellular injections of Lucifer Yellow. Ultrastructural examination demonstrated numerous markedly enlarged presynaptic terminal axons and synapses which distorted the contours of perikarya and dendrites of neurons within the prevertebral celiac/superior mesenteric and paravertebral superior cervical and stellate sympathetic ganglia of aged mice. Dilated preterminal axons had the distinctive ultrastructural appearance of neuroaxonal dystrophy, a pathologic process described in a wide variety of clinical and experimental entities. Dystrophic axons were identical in ultrastructural appearance in young and old animals, differing only in frequency. A distinctive type of ultrastructural alteration, characterized by markedly distended neurites containing numerous vacuoles, was confined to the superior cervical ganglia and also increased in frequency with aging. Although many intraganglionic vacuolated processes disappeared with surgical interruption of the cervical sympathetic trunk, which contains the preganglionic axons innervating the superior cervical ganglia, others persisted. In addition, the presence in some processes of admixed ribosomes, lipofuscin, or continuity with the cell body indicated that numerous neuritic alterations within aged sympathetic ganglia were likely of dendritic origin. Intracellular injections of Lucifer Yellow into principal sympathetic neurons demonstrated that the dendritic arborizations of the celiac/superior mesenteric ganglia neurons of young adult mice were significantly more complex and extensive than those of the superior cervical ganglia. Sympathetic neurons of aged superior cervical ganglia, but not superior mesenteric ganglia, appeared significantly smaller with regard to total dendritic length, extent, and branching when compared to those of young animals. In the aged superior cervical ganglia, short, stunted dendritic processes also exhibited large, focal, often multiple, swellings, a phenomenon infrequently observed in the superior cervical ganglia of young animals. The celiac/superior mesenteric ganglia of aged or young adult mouse failed to exhibit comparable dendritic swellings.

Evidence that the agent of equine grass sickness may reach neurons by retrograde axonal transport

Sera from acute and chronic cases of natural grass sickness or normal horses were injected into the parotid salivary gland of ponies. This gland receives its sympathetic innervation from the ipsilateral cranial cervical ganglion. None of the ponies showed any local or systemic signs of illness. After one week the cranial cervical ganglia, stellate and coeliaco-mesenteric ganglia were removed for histological study. Pathological changes were found only in the cranial cervical ganglion ipsilateral to a parotid salivary gland which had received an injection of grass sickness serum. Four out of five batches of test sera from cases of acute natural grass sickness were associated with chromatolytic changes in neurons; the remaining batch of serum produced no abnormalities. The most severe chromatolytic changes were induced by two samples obtained from horses whose signs of grass sickness had been present for less than 12 hours. A serum sample from a chronic case of grass sickness of three weeks duration did not produce chromatolysis but was associated with a moderately severe inflammatory infiltrate and neuronophagia in the ipsilateral cranial cervical ganglion. One batch of serum was size fractionated to separate components with molecular weights above or below 30 kDa. Only the fraction containing components above 30 kDa induced chromatolytic changes.

Leporine dysautonomia: further evidence that hares suffer from grass sickness

The recently described dysautonomia of hares has many similarities to equine grass sickness, particularly when the autonomic ganglia of affected hares and horses are compared by light microscopy. This study shows that the ultrastructural findings are also similar, with a loss of ribosomes from the rough endoplasmic reticulum and distension of its cisternae; the Golgi apparatus is not recognisable in affected neurons. Membranous stacks were identified in autonomic neurons of affected hares, a feature not characteristic of equine grass sickness but often found in feline dysautonomia. Staining with wheat germ agglutinin, a lectin recognising Golgi membranes, showed a lack of reactivity in affected neurons again suggesting a lack of a normal Golgi apparatus.

Hypertrophy of stellate ganglion cells in hypertensive, but not hyperactive, rats

The dendritic complexity of peripheral autonomic neurons is positively matched with the size of the target they innervate, apparently by trophic interactions with the target (D. Purves, W. D. Snider, and J. T. Voyvodic. Nature Lond. 336: 123-128, 1988). We have asked whether the vascular hypertrophy associated with hypertension is accompanied by dendritic hypertrophy of sympathetic ganglion cells. To do this, we examined the morphology of stellate ganglion cells in the spontaneously hypertensive rat (SHR), its normotensive control Wistar-Kyoto rat (WKY), and two new strains derived from the SHR that independently express the hypertensive phenotype of the SHR (WKHT) and the behavioral hyperactivity present in the SHR (WKHA). Cells were examined by intracellular staining with horseradish peroxidase in in vitro preparations of the ganglia. Carotid arterial wall size was also examined. Significant hypertrophy of both the carotid arterial wall and stellate ganglion cell dendrites was observed in the two hypertensive strains (SHR and WKHT) but not in either of the normotensive strains (WKY and WKHA). This increased total dendritic length of stellate ganglion cells associated with hypertension provides a greater target area for preganglionic innervation that may result in hyperinnervation of these cells.

Antibodies to fibronectin bind to plaques and other structures in Alzheimer's disease and control brain

Antibodies to fibronectin (Fn) bind not only the basal lamina in Alzheimer's disease brain, but also crystal-like formations in the grey matter, senile plaques, a subset of neuronal perikarya, and large highly processed stellate formations which were both neurofilament and glial fibrillary acidic protein (GFAP) negative and which were identified at a lower frequency in non-demented control brains.

Morphometric study of the superior cervical and stellate ganglia of spontaneously hypertensive rats during the prehypertensive stage

To compare the functional state of the superior cervical (SCG) and stellate sympathetic ganglia (SG) of spontaneously hypertensive rats (SHR) with those of age-matched normotensive Wistar Kyoto rats (WKY), ganglion cell volume and area occupied by ganglion cells relative to each whole ganglionic area were morphometrically examined using the Texture Analyse System (TAS) in rats at 0, 10 and 30 days of age. The weight of each ganglion relative to animal weight was also measured. The ganglion cell volume and the relative area of ganglionic cells in both ganglia of SHR were significantly larger (P less than 0.05) than those of age-matched WKY at ages 0 and 10 days after birth. The relative ganglionic weights of SHR were significantly larger (P less than 0.01) compared with those of WKY at all ages examined, except for SG at 0 days after birth. These results show that the relative volume of sympathetic ganglion cells is greater in both SCG and SG of SHR than that of WKY, suggesting that hyperfunction of sympathetic ganglia occurs at the prehypertensive stage as a primary factor in the development of hypertension in SHR.

Long QT syndrome associated with inflammatory degeneration of the stellate ganglia

A well-studied case of intermittent long QT syndrome in a 21-year-old female is presented. Electrophysiologic investigation repeated three times revealed changing sinoatrial and atrioventricular dysfunction and nonsustained ventricular tachycardia. The patient died 29 months after first hospitalization in a stage of electromechanical dissociation after runs of torsade de pointes although she had been treated with repeated anti-inflammatory therapy as well as high doses of propranolol. Postmortem examination demonstrated active inflammation of stellate ganglia. Myocardium appeared normal.

Studies on the pathogenesis of heart lesions in dogs infected with pseudorabies virus

Pseudorabies virus was inoculated by various routes into dogs to determine the relationship of pseudorabies virus to the development of heart lesions. Electrocardiograms and serum samples for lactate dehydrogenase isoenzymes were taken twice daily. Transitory and persistent arrhythmias were a consistent finding. Heart lesions were noted within each of the inoculated groups. These changes varied from severe multifocal areas of hemorrhage and myocardial degeneration to small zones of myolysis. A ganglioneuritis of the stellate ganglia and autonomic ganglia within the heart were also consistent findings. Herpes-like viral particles were found by electron microscopy in various autonomic ganglia and in myocardial endothelial cells. No viral particles were found in myocardial cells. Significant increases in lactate dehydrogenase-1 were noted. It was concluded that fatal arrhythmias resulted from pseudorabies virus infections in the dog after the occurrence of myocardial and ganglionic lesions.

Pathologic changes in the cardiac conduction and nervous system in sudden coronary death

The arrhythmogenic substrates for sudden coronary death were studied in 13 autopsied hearts and in 2 left stellate ganglia (surgically excised). Diffuse or segmentary obstruction of nutritional arteries accounted for acute ischemic injury of the conduction system, which was the underlying cause of high-risk bradycardic arrhythmias in one-third of the cases. However, in one-quarter of the cases the survival of anoxia-resistant subendocardial specialized fibers was probably responsible for reentrant lethal tachycardic arrhythmias. In other cases, early infarct damage could have fatal arrhythmias of either type. Intrinsic and/or extrinsic neuropathologic changes, unbalancing the autonomic action on the heart, were often seen to participate in the arrhythmogenic features of sudden coronary death.

[Histometric characteristics of capillary-glio-neurocytic relationships of cervicothoracic (stellate) ganglia of cats during experimental isadrine-induced myocardial necrosis]

Focal myocardial necrosis in cats (Felis domestica) was provoked by means of threefold subcutaneous administrtion of isadrin at a rate of 10 mg bw. Cervicothoracic nodes of the boundary sympathetic trunk normally and experimentally were subjected to morphologic and histometric analysis (after 3 hours, 3--7 days and 2 weeks). The presence of foci of myocardial necrosis was supported by electrocardiography data and histologic examination of the myocardium. Histometric analysis of the cervicothoracic nodes revealed shifts in the microcirculatory channel and in the neurocytic-glial complexes. A correlation was revealed between the time course of electrocardiography data on focal myocardial necrosis and consistently developing time-dependent histopathologic changes in the cervicothoracic nodes which are specific for them in acute metabolic myocardial necroses.

Dysautonomia in Parkinsonism: a clinicopathological study

Necropsy studies were done on six patients with idiopathic paralysis agitans, one with multiple system atrophy including features of Parkinsonism, and one control. Autonomic functions had been evaluated during life to a varying degree. Intra-arterial blood pressure studies were carried out on two patients with paralysis agitans (cases 4 and 6) and the one with multiple system atrophy (case 7). Lewy bodies with or without cell loss were seen in the sympathetic ganglia of five cases of paralysis agitans. Three of these had orthostatic hypotension and the severity of the lesion approximately correlated with the degree of hypotension. It is concluded that the lesions of the sympathetic ganglia may play a major role in the production of orthostatic hypotension in idiopathic paralysis agitans.