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Coronary distending pressure and delayed myocardial ischemia.

The role of blood pressure alterations in the delayed onset of myocardial ischemia following sympathetic stimulation was studied in seven anesthetized dogs. In the presence of coronary stenosis, stimulation of the left stellate ganglion produced significant increases in heart rate and mean aortic pressure, but not in mean coronary blood flow or intracoronary pressure. Following cessation of stimulation, heart rate and aortic pressure returned to control levels over a 1- to 2-minute period. During this time, there was a progressive coronary vasoconstriction, as indicated by a significant fall in coronary arterial flow and intracoronary pressure. When the hypertensive response to stellate stimulation was prevented by controlled exsanguination, the coronary vasoconstriction was not delayed but occurred during stimulation. In the second phase of experiments, the aorta was constricted so as to raise systemic pressure to the peak level achieved during stimulation. Elevation of systemic pressure consistently restored coronary arterial blood flow and intracoronary pressure to the control values. By contrast, induction of hypertension by restimulation of the stellate ganglion failed to reverse the delayed coronary vasoconstriction. We conclude that delayed myocardial ischemia results from the imbalance between coronary distending pressure and an alpha-adrenergically mediated vasoconstrictor activity that persists following cessation of sympathetic nervous system stimulation.

Animals↗

Orexin neurons project to diverse sympathetic outflow systems.

The viral transneuronal labeling method was used to demonstrate that orexin-containing neurons of the lateral hypothalamic area (LHA) are linked via multisynaptic connections to different sympathetic outflow systems. Two different types of transneuronal tracing experiments were performed: single- and double-virus studies. In the first series of experiments, Bartha pseudorabies virus (PRV), a retrograde transneuronal tracer, was injected into single sympathetic targets, viz., stellate ganglion, adrenal gland, celiac ganglion, and kidney. Six to 7 days post-injection, orexin (hypocretin) neurons were transneuronally labeled. In a second set of experiments, the double-virus tracing method was used to determine whether single orexin LHA neurons are linked to two different sympathetic outflow systems. Two isogenic forms of Bartha PRV were used that differed by a single gene. beta-Galactosidase Bartha PRV was injected into the stellate ganglion and green fluorescent protein Bartha PRV into the adrenal gland of the same rat. The reverse placement of viral injections was made in another set of rats. In both paradigms, some orexin LHA neurons were transneuronally labeled with both viruses, indicating that they are capable of modulating multiple sympathetic outflow systems. These findings raise the possibility that orexin LHA neurons regulate general sympathetic functions, such as those that occur during arousal or the fight-or-flight response.

Adrenergic Fibers↗

Effect of interference current on forearm vascular resistance in asymptomatic humans.

BACKGROUND AND PURPOSE: Several case reports suggest that transcutaneous application of interference current (IC) produces physical blockade of sympathetic vasoconstrictor fibers in peripheral nerves. To test this theory, we studied the effects of IC on forearm vascular resistance in asymptomatic humans. SUBJECTS: One man and four women, aged 21 to 44 years (mean = 33, SD = 12), served as subjects. METHODS: We measured forearm blood flow during IC applications over the left stellate ganglion. Forearm vascular resistance was calculated by dividing mean arterial pressure by forearm blood flow. RESULTS: Interference current did not alter flow (mean = 5.6 [SD = 1.0] versus 6.2 [SD = 1.1] mL/100 mL/min) or resistance (mean = 15.4 [SD = 3.1] versus 13.8 [SD = 2.4] units). When sympathetic outflow was augmented using lower-body suction, IC again failed to alter flow or resistance. CONCLUSION AND DISCUSSION: Interference current applied over the stellate ganglion does not alter forearm hemodynamics in asymptomatic individuals. These findings challenge the concept that IC can block sympathetic vasoconstrictor impulses in peripheral nerves.

Adrenergic Fibers↗

Coronary blood flow changes following activation of adrenergic receptors in the conscious dog.

The role of coronary vascular adrenergic receptors in changing coronary flow was studied in dogs instrumented to measure left circumflex artery blood flow (CBF), mean coronary artery blood pressure (CBP), and heart rate (HR). Norepinephrine (NE), isoproterenol (IP), and phenylephrine (PH) were injected into the left circumflex artery before and after selective intracoronary alpha- and beta 1- or combined beta 1- and beta 2-receptor blockade. NE, IP, and PH did not alter CBP (112 +/- 6 mmHg). In addition, IP and PH did not affect HR (103 +/- 4 beats/min). NE increased HR to 150 +/- 6 beats/min, which was eliminated by blocking beta 1-receptors with atenolol and by removing the left stellate ganglion. IP increased CBF from 65 +/- 9 to 115 +/- 16 ml/min (mediated by both beta 1- and beta 2-receptors). PH caused an alpha-receptor-mediated coronary vasoconstriction (42 +/- 5 ml/min), which was potentiated by beta 1- and beta 2-receptor blockade. NE caused a biphasic flow response. CBF initially increased to 117 +/- 14 ml/min (mediated predominantly by beta 1-receptors) followed by a prolonged decrease to 54 +/- 7 ml/min (mediated by alpha-receptors). Removing the left stellate ganglion did not affect the CBF response to NE. These data indicate that PH directly stimulates coronary alpha-receptors and IP stimulates myocardial beta 1- and coronary beta 2-receptors. NE also stimulates myocardial cells causing a reflex that increases HR and indirectly increases CBF. The vasoconstriction to NE and PH was not evident after pentobarbital anesthesia, whereas the coronary vasodilation and increase in HR to NE was still present.

Animals↗

Forearm sympathetic withdrawal and vasodilatation during mental stress in humans.

1. In humans, mental stress elicits vasodilatation in the muscle vascular beds of the forearm that may be neurally mediated. We sought to determine the extent to which this vasodilatation is due to sympathetic withdrawal, active neurogenic vasodilatation, or beta-adrenergically mediated vasodilatation. 2. We simultaneously measured forearm blood flow and muscle sympathetic nerve traffic to the forearm during mental stress in humans. In a second study, we measured forearm blood flow responses to mental stress after selective blockade of alpha-adrenergic neurotransmission in one forearm. In a final study, we measured forearm blood flow responses to mental stress after unilateral anaesthetic blockade of the stellate ganglion, alone or in combination with selective beta-adrenergic receptor blockade of the forearm. 3. During mental stress, muscle sympathetic nerve activity decreased from 5113 +/- 788 to 1509 +/- 494 total integrated activity min-1 (P < 0.05) and forearm vascular resistance decreased from 96 +/- 29 to 33 +/- 7 mmHg (dl of tissue) min ml-1 (P < 0.05). Considerable vasodilation was still elicited by mental stress after selective blockade of alpha-adrenergic neurotransmission. Vasodilatation also occurred during mental stress after stellate ganglion blockade. This dilatation was reduced by selective blockade of beta-adrenergic receptors in the forearm. 4. Our results support a role for both sympathetic withdrawal and beta-adrenergic vasodilatation as the major causes of the forearm vasodilatation during mental stress in humans.

Adolescent↗

Reflex sympathetic dystrophy: alternative modalities for pain management.

For the patient presenting with early symptoms (< 6 months) I usually start treatment with a dose pack of methylprednisolone, analgesics, and daily occupational/physical therapy for 2 weeks (Fig. 2). If they do not respond within the first week, I add stellate ganglion blocks and acupuncture to the treatment regimen. For patients presenting with established chronic pain, I immediately start them on a dose pack of methylprednisolone for 1 to 2 weeks, a nonsteroidal anti-inflammatory such as indomethacin, 50 mg 3 times a day for 10 days and then switch to 75 mg twice daily until there is a response. Amitriptyline is helpful for sleep and depression and also has a beneficial effect on blood flow. Calcium channel blockers (nifedipine) may help improve peripheral circulation by its effect on vascular smooth muscle. In this patient group, I almost always start stellate ganglion blocks on the first visit. I have the patient try at least 2 blocks before deciding whether or not blocks are helpful. Many patients will not respond to the first block, but will start to respond after the second block. If the blocks are helping, I recommend 3 blocks a week, every other day for 3 weeks. Patients get the most benefit from their blocks if they have occupational or physical therapy immediately following the block. Surgical sympathectomy may be helpful but only in patients who have responded to sympathetic blockade.

Acupuncture Therapy↗

Long QTc and torsades de pointes in human immunodeficiency virus disease.

Three patients with human immunodeficiency virus (HIV) infection presented with QT, prolongation (> 440 ms) and torsades de pointes. We sought to evaluate the etiology of the long QT syndrome in these patients without previously identified causes for QT, prolongation, and determine the prevalence among patients with HIV infection. The three index patients underwent: (1) left stellate ganglion block; (2) beta-blocker challenge; and (3) electrocardiographic stress testing. QTc interval was measured before and after intervention. We undertook a retrospective analysis of prevalence of QTC prolongation among all patients with computerized ECGs over a 6-month period at one institution and compared it to the prevalence in hospitalized patients with HIV disease. Thirty-four thousand one hundred eighty-one patients with computerized ECGs were screened for QTc prolongation. Forty-two hospitalized patients with HI disease had computerized ECG during the same 6-month period. In the three index patients, the QTc failed to shorten with left stellate ganglion blockade, beta-blocker challenge, or stress testing, suggesting an acquired form of the long QT syndrome in these patients with HIV disease. None had previously recognized acquired causes of QT, prolongation. Mexiletine hydrochloride was useful in preventing recurrences of torsades de pointes. We observed a 7.0% prevalence of QT, prolongation among all patients screened. Hospitalized patients with HIV disease (n = 42) during this same period, demonstrated an increased prevalence of QT, prolongation (28.6%, P = 0.002). Patients with HIV disease have a significantly higher prevalence of QTc prolongation than a general hospital-based population, may have an unrecognized acquired form of the long QT syndrome, and are at risk for torsades de pointes.

Adult↗

Plasma concentrations of bupivacaine in celiac plexus block.

BACKGROUND AND OBJECTIVES: Following stellate ganglion block, systemic absorption of local anesthetics is rapid. Pharmacokinetic data for local anesthetics following other blocks, such as celiac plexus blocks, are lacking. METHODS: Plasma concentrations of bupivacaine in venous blood samples following celiac blocks were measured in 10 patients using a high-performance liquid chromatography technique; 40 mL plain bupivacaine 0.25% was administered. RESULTS: Celiac plexus block resulted in maximum plasma concentrations of 0.7-2.5 mg/L bupivacaine (mean, 1.5 +/- 0.6 mg/L). In 3 of 10 patients plasma concentrations above 2 mg/L occurred. The maximum concentrations were reached 10-30 minutes after the injection (17 +/- 8 minutes). No clinical signs of central nervous system toxicity occurred. All patients showed hemodynamic stability following the blocks. CONCLUSIONS: Maximum plasma concentrations of bupivacaine occur rather late following celiac blocks compared to stellate ganglion or intercostal blocks. The rather high plasma concentrations of bupivacaine indicate the need for appropriate clinical monitoring.

Adult↗

Differential effects of clonidine and reserpine treatment on neuropeptide Y content in some sympathetically innervated tissues of the guinea-pig.

The effects of treatment with reserpine and/or the selective alpha 2-adrenoreceptor agonists clonidine and oxymetazoline on tissue levels of neuropeptide Y (NPY)-like immunoreactivity (-LI) and noradrenaline (NA) were studied in the guinea-pig. Clonidine treatment was associated with an increase in the levels of NPY-LI in the right atrium in a time- and dose-dependent manner. A significant (45%) elevation of the right atrial content of NPY-LI was present 2 h after administration of clonidine (50 micrograms kg-1 s.c.). After 24 h of repeated clonidine treatment the atrial levels of NPY-LI had increased by 95%. Following chronic clonidine treatment for two weeks, however, the right atrial NPY levels were similar to those in control animals. The corresponding cell-body content of NPY-LI in the stellate ganglion, remained unaffected by clonidine treatment. The levels of NPY-LI were also increased in the gastrocnemius muscle, spleen and adrenal gland after clonidine treatment while no changes were detected in the vas deferens or hypothalamus. The reserpine-induced reduction of NPY-LI in the right atrium, spleen, gastrocnemius muscle and adrenal gland was markedly inhibited by concomitant clonidine treatment while no effect was observed on NA depletion. The adrenoreceptor antagonists phentolamine, prazosin and yohimbine all inhibited the increase in cardiac content of NPY-LI seen after clonidine treatment. No elevation of tissue content of NPY-LI was observed after oxymetazoline (50 micrograms kg-1 s.c.) which, however, reversed the reserpine-induced depletion of NPY-LI. The reserpine-induced increase in content of NPY-LI in the stellate ganglion was also inhibited by clonidine and oxymetazoline.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗

Periaqueductal gray matter input to cardiac-related sympathetic premotor neurons.

The periaqueductal gray matter (PAG) serves as the midbrain link between forebrain emotional processing systems and motor pathways used in the defense reaction. Part of this response depends upon PAG efferent pathways that modulate cardiovascular-related sympathetic outflow systems, including those that regulate the heart. While it is known that the PAG projects to vagal preganglionic neurons, including possibly cardiovagal motoneurons, no information exists on the PAG circuits that may affect sympathetically mediated cardiac functions and, thus, the purpose of this study was to use neuroanatomical methods to identify these pathways. First, viral transneuronal retrograde tracing experiments were performed in which pseudorabies virus (PRV) was injected into the stellate ganglion of rats. After 4 days survival, five PAG regions contained transynaptically infected neurons; these included the dorsomedial, lateral and ventrolateral PAG columns as well as the Edinger-Westphal and precommissural nuclei. Second, the descending efferent PAG projections were studied with the anterograde axonal marker Phaseolus vulgaris leuco-agglutinin (PHA-L) with a particular focus on determining whether the PAG projects to the intermediolateral cell column (IML). Almost no axonal labeling was found throughout the thoracic IML suggesting that the PAG modulates sympathetic functions by indirect pathways involving synaptic relays through sympathetic premotor cell groups, especially those found in the medulla oblongata. This possibility was examined by a double tracing study. PHA-L was first injected into either the lateral or ventrolateral PAG and after 6 days, PRV was injected into the ipsilateral stellate ganglion. After an additional 4 days survival, a double immunohistochemical procedure for co-visualization of PRV and PHA-L was used to identify the sympathetic premotor regions that receive an input from the PAG. The PAG innervated specific groups of sympathetic premotor neurons in the hypothalamus, pons, and medulla as well as providing reciprocal intercolumnar connections within the PAG itself (Jansen et al., Brain Res. 784 (1998) 329-336). The major route terminates in the ventral medulla, especially within the medial region which contains sympathetic premotor neurons lying within the raphe magnus and gigantocellular reticular nucleus, pars alpha. Both serotonergic and non-serotonergic sympathetic premotor neurons in these two regions receive inputs from the PAG. Weak PAG projections to sympathetic premotor neurons were found in the rostral ventrolateral medulla (including to C1 adrenergic neurons), locus coeruleus, A5 cell group, paraventricular and lateral hypothalamic nuclei. In summary, both the lateral and ventrolateral PAG columns appear to be capable of modulating cardiac sympathetic functions via a series of indirect pathways involving sympathetic premotor neurons found in selected sites in the hypothalamus, midbrain, pons, and medulla oblongata, with the major outflow terminating in bulbospinal regions of the rostral ventromedial medulla.

Animals↗

An analysis of the sympathetic preganglionic neurons projecting from the upper thoracic spinal roots of the cat.

The distribution of sympathetic preganglionic neurons that project via the right stellate ganglion has been studied quantitatively in adult cats. Retrograde transport of horseradish peroxidase (HRP) injected into the ganglion or applied to transected axons of the cervical sympathetic trunk (CST) resulted in labelling of neurons in the ipsilateral spinal cord over T1-T9 and T1-T7, respectively. Their distribution and morphology in the subnuclei of the intermediate zone were determined. Neurons within the principal part of the intermediolateral column (ILp) comprised the majority of labelled cells at all levels, irrespective of the site of HRP application, while more medially located neurons projected differentially. A combination of the application procedures labelled what appeared to be a sum of the individual projections, and few ILp cells remained unlabelled in the most rostral segments. From reconstructions of different segmental levels, most of the cells in the ILp were found to lie in a column approximately 200 micrometer in diameter composed of a series of cell aggregations of 20-150 neurons at intervals of approximately 300 micrometer. Less frequently, mediolaterally aligned cells extended toward the central canal, near which small cell clusters were also detected. After selective HRP application to individual rami of T1-T3, labelled cells were restricted to one segment's length, so that neurons located more caudally must project extraspinally to the stellate ganglion. Consideration of the maximum cell numbers labelled by each procedure suggests that preganglionic collaterals (probably unmyelinated) diverging from the pathway to the preferred target of their parent neuron were not labelled by this technique.

Animals↗

T wave alternans as a predictor of spontaneous ventricular tachycardia in a canine model of sudden cardiac death.

INTRODUCTION: We recently developed an ambulatory canine model of spontaneous ventricular tachycardia (VT) and sudden cardiac death by creating myocardial infarction, complete AV block, and infusion of nerve growth factor to the left stellate ganglion. Whether or not T wave alternans is associated with the spontaneously occurring episodes of VT in our model was unclear. METHODS AND RESULTS: Through intracardiac electrograms obtained from an implantable cardioverter defibrillator, we manually measured T wave amplitudes prior to VT and while the dogs were at rest (baseline, no VT). Of the 79 VT episodes analyzed, 28 (35.4%) exhibited repolarization alternans. In contrast, only 3 (4.7%) of 64 baseline data cases displayed alternans (P < 0.0001). The magnitude of T wave alternans for dogs that died of sudden cardiac death, dogs that did not die suddenly, and for the total 28 episodes that exhibited repolarization alternans were 4.8 +/- 2.8 mm, 4.9 +/- 3.5 mm, and 4.9 +/- 3.3 mm, respectively (P = NS). We also found the sensitivity, specificity, positive predictive value, negative predictive value, and relative risk of repolarization alternans in predicting VT to be 35.4%, 95.3%, 90.3%, 54.5%, and 1.98, respectively. The ventricular rate prior to VT (65 +/- 11 beats/min) was significantly higher than that at rest (49 +/- 12 beats/min; P < 0.0001). CONCLUSION: T wave alternans often occurred immediately before the onset of VT in dogs with myocardial infarction, complete AV block, and nerve growth factor infusion to the left stellate ganglion. Increased sympathetic activity might be responsible for the occurrence of the T wave alternans.

Animals↗

Vagal, sympathetic and somatic sensory inputs to upper cervical (C1-C3) spinothalamic tract neurons in monkeys.

1. Myocardial ischemia activates vagal and sympathetic cardiac afferent fibers. The purpose of this study was to determine a neuro physiological basis for cardiac pain referred to C1-C3 somatic dermatomes. We hypothesized that afferent fibers traveling in vagal or sympathetic nerves transmit nociceptive information to C1-C3 spinothalamic tract (STT) neurons. 2. Electrical stimulation of the left stellate ganglion to excite cardiopulmonary sympathetic afferent fibers increased extracellular activity of 44 of 77 C1-C3 STT neurons examined in 33 anesthetized male monkeys (Macaca fascicularis); responses increased as stimulus strength increased. Additionally, this stimulus inhibited 5 cells, increased/decreased activity of 2 cells, and did not affect 26 cells. 3. Electrical stimulation of the left (ipsilateral) thoracic vagus nerve excited 41 of 78 C1-C3 STT neurons, inhibited 4 neurons, increased/decreased activity of 2 neurons, and did not affect 31 neurons. Responses increased with increasing stimulus strength Contralateral vagal stimulation excited 7 of 39 cells tested, inhibited 4 cells and did not affect 28 cells. 4. Effects of stimulating one or more vagal branches were examined on 22 C1-C3 STT neurons excited by input from left thoracic vagus nerve. Stimulation of the cardiac branch excited 11 of 16 cells tested; stimulation of the recurrent laryngeal nerve excited 11 of 18 cells; stimulation of vagal fibers just rostral to the diaphragm excited 8 of 19 cells. 5. Excitatory somatic receptive fields ranged from small ipsilateral fields to large, sometimes bilateral or noncontinuous fields. Many fields included the ipsilateral neck and/or inferior jaw. Thirty-nine of 74 neurons examined were wide dynamic range (WDR), 21 were high threshold (HT), 6 were low threshold (LT), and 8 did not respond to brushing or noxious pinching of somatic tissues. Most (38 of 39) WDR cells responded to stimulation of the stellate ganglion or vagal fibers, as did 18 of 21 HT cells, 3 of 6 LT cells, and 2 of 8 cells unresponsive to brush or pinch stimuli. 6. Results of this study supported the concept that vagal and/ or sympathetic afferent activation of C1-C3 STT neurons might provide a neural mechanism for referred pain that originates in the heart or other visceral organs but is perceived in the neck and jaw region. Additionally, C1-C3 STT neurons processed sensory information from widespread regions of the body.

Adrenergic Fibers↗

Activation of feline spinal neurones by potentiated ventricular contractions and other mechanical cardiac stimuli.

1. Neurones in the spinal cord were tested for responses to premature ventricular contractions (PVCs), produced by controlled electrical extra stimuli, and other mechanical stimuli applied to the heart. Thirty-eight neurones were antidromically activated from the medial medullary reticular formation and/or the caudal thalamus, and twenty-four neurones did not project to these sites. 2. Only those neurones excited by electrical stimulation of the left stellate ganglion were tested for responses to PVCs. A total of twenty neurones (32%) responded to electrically induced PVCs. Three major patterns of responses occurred. Three neurones exhibited an early burst and a late burst (or bursts) during the arrhythmia, one neurone fired only an early burst, and sixteen neurones responded with only a late burst. The early bursts occurred shortly after the onset of the compensatory pause accompanying the PVC; the late bursts were usually associated with the subsequent potentiated contraction, although the stimulus eliciting the burst must often have occurred late in the compensatory pause. 3. Responses to PVCs were only seen in neurones receiving C fibre and A delta fibre input. However, there were some neurones with both A delta and C input that did not respond to PVCs. No neurones with only A delta input responded to PVCs. 4. Neurones projecting to thalamus were less likely to respond to PVCs than either spinoreticular neurones or neurones with unidentified projections. 5. Neurones responsive to PVCs were likely to exhibit a cardiac rhythmicity in their spontaneous or evoked activity. 6. A total of 42% of tested neurones responded to a rapid infusion of saline into the heart, 52% had a cardiac receptive field, and 74% responded to aortic occlusion. A given neurone might respond to one or more of these stimuli, without responding to every mechanical stimulus tested. 7. Cervical vagotomy never abolished a response to PVCs, although either the spontaneous discharge rate or magnitude of response was sometimes altered. 8. Neurones responsive to PVCs were also responsive to intracardiac bradykinin. In addition, 95% of the neurones received convergent somatic input. 9. We conclude that about a third of spinal neurones excited by electrical stimulation of the left stellate ganglion receive information regarding mechanical, presumably innocuous, events in the heart. Most responsive neurones also receive somatic input and noxious cardiac input, and this information is transmitted to the thalamus, reticular formation, and probably to other spinal segments.

Action Potentials↗

Responses of medullary raphespinal neurons to coronary artery occlusion, epicardial bradykinin, and cardiac mechanical stimuli in cats.

1. A total of 59 medullary raphespinal neurons antidromically activated from the T2-T5 segments were tested for responses to coronary artery occlusion, epicardial application of bradykinin, and mechanical probing of the epicardium in cats anesthetized with alpha-chloralose. With the exception of five neurons, only those neurons that were responsive to electrical stimulation of the left stellate ganglion were tested for responses to these stimuli. Neurons in this study are a subset of those in the companion report. 2. Six neurons (12%) responded to epicardial bradykinin. Five cells were excited, and one was inhibited. Nine neurons (18%) had cardiac receptive fields, and one neuron (2%) had a field confined to the pericardium. 3. Neurons were tested for responses to separate occlusions of the left anterior descending (LAD) and circumflex (CX) coronary arteries. Overall, 13/34 (38%) of tested raphespinal neurons were responsive to coronary artery occlusion. Responses to coronary artery occlusion consisted of two major patterns. One pattern consisted of either an increase or decrease in neuronal firing rate after the heart became ischemic; this pattern was termed an ischemic (IS) response. Ten neurons (29%) exhibited an IS response to occlusion of the LAD and/or CX coronary arteries. Because four neurons exhibited IS responses to occlusion of each artery, there were a total of 14 IS responses. Of these, 10 were inhibitory, and 4 were excitatory. The second pattern of response consisted of a rapidly adapting excitation or inhibition at the onset or release of occlusion, but cell activity was unchanged during cardiac ischemia; this pattern was termed an onset (ON) response. Three neurons (9%) exhibited ON responses; two were excited, and one was inhibited. No neurons demonstrated both ON and IS responses during occlusion. 4. Twenty-one neurons were tested for responses to occlusion of each artery. Seventeen neurons (81%) exhibited similar patterns of responses to occlusion of each artery; that is, they either showed the same pattern of response to occlusion of each artery or they were unresponsive to either occlusion. For the 5 of these 17 neurons that were responsive, direction of change in neuronal activity (excitation or inhibition) was the same for occlusion of each artery. 5. All raphespinal neurons tested for responses to epicardial bradykinin and coronary artery occlusion were responsive to electrical stimulation of the left stellate ganglion. In addition, 16/28 (57%) of neurons tested for responses to occlusion were responsive to electrical stimulation of the right cervical vagus nerve.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

[A 56-year-old man with fever, backache and tetraparesis].

We report a 56-year-old man who developed progressive paraparesis. He was apparently well, except for left Bell's palsy which developed on May 9 of 1994, for which he received stellate ganglion block on the left side more than ten times until July 2nd of 1994, when he noted pain in his left shoulder and in his lumbar region. On July 5th, he noted some difficulty in urination. On July 6th, he noted tingling sensation in his four extremities and difficulty in gait. He was admitted to another hospital where he was treated with intravenous infusion of glycerol. After this treatment, his gait and sensory disturbance showed some improvement, however, on July 7th, his shoulder and lumbar pain worsened, and he became unable to stand. His temperature went up to 39 degrees C on the next day. Lumbar CSF on that day contained 119 cells/microliters, 112 mg/dl of protein, and 53 mg/dl of sugar. He was transferred to our hospital on July 14th. His past medical history revealed that he had suffered from frequent bouts of osteomyelitis since the age of 13 years. He was operated on several times on osteomyelitis. He had been treated on his tooth ache until shortly before the onset of the present illness. He also received steroid hormone for his Bell's palsy. On admission, his consciousness varied from alert to stupor. His BP was 150/100 mmHg, HR 98/min and regular, BT 39.4 degrees C. The bulbar conjunctiva appeared somewhat icteric. Otherwise, general physical examination was unremarkable. On neurologic examination, there was no apparent dementia. Higher cerebral functions appeared intact. The optic discs were flat. Pupils were round and isocoric reacting to light and accommodation promptly. Ocular movements were full without nystagmus. Some exophthalmos was noted bilaterally. The sensation of the face and facial muscles were intact. The remaining cranial nerves also appeared intact. Nuchal rigidity was present. He was unable to stand or walk. Muscle strength was markedly diminished in all four limbs; manual muscle testing revealed 1 to 2/5 weakness in both upper and lower extremities bilaterally. Muscle stretch reflexes were decreased or lost in both upper and lower limbs, but the plantar response was extensor on the right. Sensation appeared to be diminished in legs, but detail was not clear because of disturbance of consciousness. Pertinent laboratory findings were as follows: WBC 12,800/microliter, GPT 58 IU/l, total bilirubin 2.65 mg/dl, and CRP 16.8 mg/dl. Cerebrospinal fluid contained 34 cells/microliter (approximately two thirds were neutrophils), RBC 1,110/microliter, 2,949 mg/dl of protein, and 119 mg/dl of glucose; stapylococcus aureus was cultured from the CSF. Myelogram showed a filling defect in the anterior epidural space between the low thoracic and the upper lumbar region. The patient was treated with cephotaxim, aminobenzyl penicillin, and chloramphenicol. On the second hospital day, his BT was still 39 degrees C and he was agitated His weakness was worse than the previous day. Spinal MRI was attempted; as he was agitated 5 mg of diazepam was given intravenously at 4 PM. His respiration was rapid and somewhat shallow. At 6 PM, gadolinium DTPA was injected intravenously; at that time, he was breathing and pupils were 3 mm on both sides. At 6:35 PM, an examiner noted that he stopped breathing; the left pupil was dilated to 5 mm. Cardiopulmonary resuscitation was initiated immediately, and intubation was performed. He was placed on a respirator. His blood pressure did not reach 100 mmHg; he was in deep coma. Cardiac arrest occurred at 8:53 AM on the next morning. The patient was discussed in a neurological CPC. Most of the participants thought that the patient had either spinal epidural empyema or spinal subdural abscess. The question was what might be the original focus of infection. Three possibilities were considered, i.e., stellate ganglion block, teeth infection, and osteomyelitis...

Back Pain↗

Torsades de pointes ventricular tachycardia following right pneumonectomy: insights into the relation between right cardiac sympathetic nerve damage, QT intervals, and arrhythmias.

Polymorphic ventricular tachycardia in association with prolongation of the QT interval on the surface electrocardiogram (ECG) has long been recognized as an important cause of life threatening arrhythmias that can occur with congenital or acquired abnormalities of cardiac repolarization. One hypothesis of the origin of these arrhythmias states that overactivity of the left-sided sympathetic or under activity of the right-sided sympathetic neural input to the heart leads to prolonged repolarization and ventricular arrhythmias. This hypothesis has led to the application of left cervicothoracic sympathetectomy for control of arrhythmias in congenital long QT syndromes. Although animal models have shown QT prolongation following right stellate ganglionic section or left stellate stimulation, spontaneous ventricular arrhythmias following stellate stimulation or block in man have not been demonstrated. We report the case of a patient with life threatening ventricular arrhythmias following surgical damage to the right cardiothoracic sympathetic nerves.

Electrocardiography↗

Hypoperfusion of the myocardium relative to myocardial metabolism during delayed coronary constriction.

OBJECTIVE: The aim was to test the hypothesis that the myocardium becomes hypoperfused, relative to its metabolic demands, during the delayed coronary constriction which is observed following termination of a period of sympathetic stimulation. METHODS: This was tested by beat by beat analysis of the ratio of coronary blood flow to the product of heart rate and systolic blood pressure (HR x SBP), an index of myocardial metabolism, in acutely instrumented open chest canine preparations, before, during, and after direct electrical stimulation of the left stellate ganglion. RESULTS: Myocardial metabolism increased in response to stellate stimulation, as evidenced by increases in heart rate, aortic blood pressure, and HR x SBP. These were accompanied by increased blood flow and decreased vascular resistance in the left anterior descending coronary artery. Delayed coronary constriction, defined as the period with the lowest coronary blood flow observed after the end of the stimulation, occurred 1 to 3 min after stimulation was terminated and was characterised by recovery of heart rate, blood pressure, HR x SBP, and coronary blood flow toward control levels, while coronary vascular resistance overshot to above control levels. The ratio of coronary blood flow to HR x SBP fell progressively in the poststimulation period to significantly less (mean 0.715, range of +/- 1 SEM 0.638 to 0.800, p < 0.05) than control (1.0, by definition) in experiments performed with partial prestenosis of the left anterior descending coronary artery. In a selected subgroup of observations with a mean reduction in coronary blood flow during delayed coronary constriction comparable to that reported previously, the flow/metabolism ratio was even lower (mean 0.239, range of +/- 1 SEM 0.202 to 0.284). CONCLUSIONS: The phenomenon of delayed coronary constriction clearly involves a mismatch between myocardial supply and demand: coronary blood flow becomes inappropriately low for the prevailing level of myocardial metabolism.

Animals↗