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At least 325 records · Page 18Linked to original sources
PubMed1999

Myocardial ischaemia and the cardiac nervous system.

The intrinsic cardiac nervous system has been classically considered to contain only parasympathetic efferent postganglionic neurones which receive inputs from medullary parasympathetic efferent preganglionic neurones. In such a view, intrinsic cardiac ganglia act as simple relay stations of parasympathetic efferent neuronal input to the heart, the major autonomic control of the heart purported to reside solely in the brainstem and spinal cord. Data collected over the past two decades indicate that processing occurs within the mammalian intrinsic cardiac nervous system which involves afferent neurones, local circuit neurones (interconnecting neurones) as well as both sympathetic and parasympathetic efferent postganglionic neurones. As such, intrinsic cardiac ganglionic interactions represent the organ component of the hierarchy of intrathoracic nested feedback control loops which provide rapid and appropriate reflex coordination of efferent autonomic neuronal outflow to the heart. In such a concept, the intrinsic cardiac nervous system acts as a distributive processor, integrating parasympathetic and sympathetic efferent centrifugal information to the heart in addition to centripetal information arising from cardiac sensory neurites. A number of neurochemicals have been shown to influence the interneuronal interactions which occur within the intrathoracic cardiac nervous system. For instance, pharmacological interventions that modify beta-adrenergic or angiotensin II receptors affect cardiomyocyte function not only directly, but indirectly by influencing the capacity of intrathoracic neurones to regulate cardiomyocytes. Thus, current pharmacological management of heart disease may influence cardiomyocyte function directly as well as indirectly secondary to modifying the cardiac nervous system. This review presents a brief summary of developing concepts about the role of the cardiac nervous system in regulating the normal heart. In addition, it provides some tentative ideas concerning the importance of this nervous system in cardiac disease states with a view to stimulating further interest in neural control of the heart so that appropriate neurocardiological strategies can be devised for the management of heart disease.

Arrhythmias, Cardiac↗
PubMed1999

Genesis and role of coordinated firing in a feedforward network: a model study of the enteric nervous system.

The enteric nervous system can generate complex motor patterns independently of the central nervous system. The ascending enteric reflex pathway consists of sensory neurons, long chains of a single class of orally directed interneuron and excitatory motor neurons. Because of the importance of this pathway in peristalsis, it was modelled from the firing of sensory neurons through to muscle membrane activation. The model was anatomically realistic in the number of neurons simulated and in the patterns of connections between neurons. The model was also realistic in the simulation of ligand-gated currents in neuron and muscle membrane, current flow in the muscle syncytium and voltage-dependent currents in muscle. Sensory neurons were activated in a manner consistent with a brief mechanical stimulus. Transmission between sensory neurons and first-order interneurons was by slow excitatory transmission, which caused interneurons to fire continuously for several hundred milliseconds. Interneurons then transmitted to higher order interneurons by fast excitatory postsynaptic potentials, each lasting for around 40 ms. As the activity propagated along the pathway, random firing became progressively more synchronized between neurons, until the network as a whole was firing in a coordinated manner. The coordinated firing was a robust phenomenon over a wide range of network and neuron parameters. It is therefore possible that this is a general property of feedforward networks that receive high levels of sustained input. The smooth muscle model indicated that bursting input to the muscle may increase the likelihood of muscle cells firing action potentials when compared with uniform input. In addition, the syncytium model explains how the predicted muscle excitation might be related to current experimental observations.

Action Potentials↗
PubMed1988

Early recognition of toxicity by assessing nervous system function.

Many industrial substances, such as pesticides, solvents, and heavy metals, are toxic to the human nervous system. Nervous system function provides an excellent means for assessing the early effects of toxic substances. A large percentage of occupational chemicals that are recognized to produce adverse health effects in general also adversely affect the nervous system. Reliable and low-cost methods, including psychometric tests and nerve conduction velocity assessment, have been developed for evaluating nervous system function. By monitoring nervous system function in workers exposed to neurotoxic chemicals, early signs of chemical toxicity can be detected. Appropriate action following detection of early signs of neurotoxicity may then avert permanent and debilitating nervous system disorder and may help to limit exposure to toxic substances affecting other organ systems as well as the nervous system. A monitoring program along with its rationale is described in this paper.

Brain Diseases↗
PubMed1984

Distribution of the histaminergic neuron system in the central nervous system of rats; a fluorescent immunohistochemical analysis with histidine decarboxylase as a marker.

The distribution of histidine decarboxylase-like immunoreactivity (HDCI) in the rat central nervous system was studied by the indirect immunofluorescence technique. HDCI cell bodies were concentrated in the posterior hypothalamic area, such as in the tuberal magnocellular nucleus, caudal magnocellular nucleus, posterior hypothalamic nucleus and lateral hypothalamus just lateral to the fasciculus mammillothalamicus at the level of the posterior hypothalamic nucleus. Extensive networks of HDCI fibers of various densities were found in many areas of the brain; they were particularly dense in the hypothalamus but were also found in the following areas: rostrally in the cerebral cortex, olfactory nuclei, medial amygdaloid nucleus, n. tractus diagonalis, and bed nucleus of the stria terminalis, and caudally in the central gray matter of the midbrain and pons, auditory system, n. vestibularis medialis, n. originis nervi facialis, n. parabrachialis, n. commissuralis, n. tractus solitarii, and n. raphe dorsalis.

Animals↗
PubMed1988

Diagnosis of central nervous system lupus.

Central nervous system (CNS) involvement in systemic lupus erythematosus is a major source of patient morbidity and mortality. The recognition of nervous system lupus is hampered by the diagnostic insensitivity and non-specificity of the various testing modalities that are currently available. A review of the effectiveness of diagnostic tests for CNS lupus is presented. Areas of current research in this area are examined. Because of the diversity of neurologic manifestations in this disorder and their complex pathogenesis, no single test is sufficient to establish the diagnosis rapidly and accurately in all cases, now or for the foreseeable future.

Central Nervous System Diseases↗
PubMed1992

[Autonomic dysfunction of central nervous system disorders].

Central nervous system disorders, such as cerebrovascular or spinal cord lesions often cause dysfunctions of the autonomic nervous system. In most cases of acute cerebrovascular accidents, blood pressure is transiently elevated. Some patients, especially with pontine or thalamic hemorrhage, suffer from extremely high fever. In patients with large lesions in the cerebral hemisphere or lesions in the brainstem, cardiopulmonary state may be affected. In spite of absence of acute myocardial infarction, electrocardiogram may show ST-T changes resembling acute myocardial infarction. Cheyne-Stokes respiration or sleep apnea can occur. Lesions in the medulla oblongata cause dysfunctions of automatic respiration. Patients with large cerebrovascular lesions in the unilateral hemisphere often show transient hyperhidrosis on the contralateral side. Prognosis of patients with these autonomic failures is poor. In patients with spinal shock, blood pressure and heart rate are reduced. In chronic stage, autonomic hyperreflexia, such as attacks of episodic hypertension can occur. Lesions in the high cervical cord often bring nonsymptomatic perforating gastric ulcer.

Autonomic Nervous System Diseases↗
PubMed2002

Primary nervous system lymphoma.

Primary nervous system lymphoma (PNSL) is a rare type of non-Hodgkin's lymphoma confined to the nervous system. Although significant progress has been made in the treatment of PNSL over the past decade, patients with this disease are rarely cured. Until recently, whole brain radiation therapy has been the standard treatment for PNSL. However, whole brain radiation therapy is associated with a high relapse rate and late neurotoxicity after chemotherapy, especially in patients older than 60 years of age. Methotrexate-based chemotherapy has become the standard approach to treat patients with newly diagnosed PNSL. Ongoing research efforts are focused on identifying chemotherapeutic agents with good antilymphoma activity that penetrate the blood-brain barrier. The roles of intrathecal chemotherapy and blood-brain barrier disruption are not fully defined. Given the rarity of this tumor, patients with PNSL should be referred to tertiary cancer centers where ongoing clinical trials are underway to identify the optimal treatment of PNSL.

Antineoplastic Agents↗
PubMed1998

III. Role Of the RET signal transduction pathway in development of the mammalian enteric nervous system.

The enteric nervous system (ENS) in vertebrates is derived from the neural crest and constitutes the most complex part of the peripheral nervous system. Natural and induced mutagenesis in mammals has shown that the tyrosine kinase receptor RET and its functional ligand glial cell line-derived neurotrophic factor (GDNF) play key roles in the development of the ENS in humans and mice. We have developed and briefly describe here a number of assays that analyze the specific function of the RET receptor and its ligand. Our data suggest that the RET signal transduction pathway has multiple roles in the development of the mammalian ENS.

Animals↗
PubMed2000

[Sympathetic nervous system correlates of emotional tension in subjects with different status of the autonomic nervous system].

86 miners (age of 30-40) of coal miners were examined. It was ascertained that the level of tension of neurohumoral mechanisms of regulation of myocardium activity and splanchnic function of organism in emotiongenic conditions is determined by the condition of ANS. The secretion of noradrenaline of normotonics prevails, peripheral and central mechanisms of vegetative regulation of chronotropic function of heart start their work, tone of resistive vascular resis slightly. The discharge of adrenaline to blood of vago- and sympatotonic prevails, considerable tension of mechanisms of vegetative regulation of myocardium and expressed rise of tone resistive vascular and breathing frequency are observed. People with parasympatotonic are noted to have the biggest tension of splanchnic and regulative systems. The lower emotional steadiness is typical for them.

Adult↗
PubMed1990

The anatomy of the visceral and autonomic nervous systems.

The visceral nervous system has several levels of anatomical organization. Individual viscera, including the heart and the intestines, have neural tissue embedded in their walls that is capable, under some circumstances, of a truly autonomic self-regulation of that organ's activity. This self-regulation will not respond to all the varying needs of the organ control, particularly when external or internal changes affect the whole animal. The parasympathetic, sympathetic, and visceral afferent systems and their CNS connections are the next level of reflex neural organization. A greater degree of central regulation is managed at this level. The third level of visceral control is located in the brainstem and includes the hypothalamus, parts of the reticular formation, and cardiorespiratory centers in the medulla. These visceral upper neuron centers exert a high degree of control over the parasympathetic and sympathetic LMN centers of the brainstem and spinal cord. The reticulobulbar and reticulospinal pathways are the means by which the visceral upper motor neurons communicate with the LMN systems. The hypothalamus-hypophyseal system exerts control by releasing hormones to act on distant target organs. The highest level of organization of visceral function takes place in the limbic system. The limbic system is in a position to integrate sensory information originating from both within (interoceptive) and outside (exteroceptive) the animal. Associations are made at this level and with the help of cortical association areas, memory is integrated with these sensations. The limbic system is then able to influence the hypothalamic and medullary centers as well as the somatic motor centers to develop the appropriate responses for the preservation of the animal.

Afferent Pathways↗
PubMed2000

Intrathecal cytokines in systemic lupus erythematosus with central nervous system involvement.

Symptoms originating from central nervous system (CNS) are frequently occuring in patients with systemic lupus erythematosus (SLE). Reliable diagnostic markers for this condition are presently lacking. Importantly, CNS involvement in lupus patients is associated with increased morbidity and mortality. The aim of this retrospective evaluate was to study the diagnostic value of cerebrospinal fluid (CSF) cytokine levels in SLE patients with CNS involvement. 34 patients with SLE were hospitalized and investigated for the presence of CNS lupus. These patients were evaluated clinically and with magnetic resonance imaging (MRI) and CSF analyses, as well as with neuropsychiatric tests. 13 patients were found to have CNS lupus whereas another four of the patients fulfilled the criteria for CNS involvement but were excluded from this group due to other causes of CNS involvement. Lastly, in 17 SLE cases, the diagnosis of CNS lupus could not be confirmed. CSF levels of interleukin-6 (IL-6) and IL-8, as well as the CSF/serum IL-6 ratio, were elevated in the CNS lupus group, compared with the 17 SLE patients not fullfilling a diagnosis of cerebral lupus. Interestingly, follow-up of five patients being successfully treated for CNS lupus revealed profound decrease of intrathecal IL-6 levels. These results indicate that analysis of CSF cytokine levels, especially IL-6 and IL-8, may be useful in the diagnostics and possibly follow-up of SLE patients with cerebral lupus.

Adolescent↗
PubMed2001

Structure and expression of the glycine cleavage system in rat central nervous system.

The glycine cleavage system (GCS) is a mitochondrial multienzyme system consisting of four individual proteins, three specific components (P-, T-, and H-proteins) and one house-keeping enzyme, dihydrolipoamide dehydrogenase. Inherited deficiency of the GCS causes nonketotic hyperglycinemia (NKH), an inborn error of glycine metabolism. NKH is characterized by massive accumulation of glycine in serum and cerebrospinal fluids and severe neuronal dysfunction in neonates. To elucidate the neuropathogenesis of NKH, we cloned cDNAs encoding three specific components of the GCS and studied the gene expression in rat central nervous system. P-, T-, and H-protein cDNAs encoded 1024, 403, and 170 amino acids, respectively. In situ hybridization analysis revealed that P-protein mRNA was expressed mainly in glial-like cells, including Bergmann glias in the cerebellum, while T- and H-protein mRNAs were detected in both glial-like cells and neurons. T- and H-protein mRNAs, but not P-protein mRNA, were expressed in the spinal cord. Primary astrocyte cultures established from cerebral cortex had higher GCS activities than hepatocytes whereas those from spinal cord expressed only H-protein mRNA and had no enzymatic activity. An important role of glycine as inhibitory neurotransmitter has been established in the brainstem and spinal cord and another role of glycine as an excitation modulator of N-methyl-D-aspartate receptor is suggested in the hippocampus, cerebral cortex, olfactory bulbus, and cerebellum. Our results suggest that the GCS plays a major role in the forebrain and cerebellum rather than in the spinal cord, and that N-methyl-D-aspartate receptor may participate in neuropathogenesis of NKH.

Age Factors↗