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PubMed1992

[Efficiency of the autonomic nervous system in patients with acute leukemia].

Autonomic nervous system function was examined by simple tests in 10 patients with acute myeloblastic leukemia and 10 patients with acute lymphoblastic leukemia. The results in both groups were related to the stage of the disease, clinical and hematological status and mode of chemotherapy. It was found that the functional capacity of the autonomic nervous system was significantly lower in patients with leukemias than in healthy subjects (control group). Functional abnormalities were most prominent in patients in poor clinical condition with marked anemia and during the acute phase of the disease.

Adolescent↗
PubMed1982

Autonomic nervous system abnormalities and allergy.

Abnormal autonomic nervous system responsiveness may contribute to the pathogenesis of asthma and other allergic diseases. Therefore, we measured alpha- and beta-adrenergic and cholinergic responsiveness in allergic subjects. Allergic asthmatic subjects had an abnormal adrenergic (alpha = hyperresponsive; beta = hyporesponsive) and cholinergic (hyperresponsive) profile. However, subjects with allergic rhinitis and preallergic subjects (those with positive allergen skin tests without any disease manifestation) had equivalent beta-adrenergic and cholinergic abnormalities. Thus, all allergic subjects showed abnormal beta-adrenergic hyporeactivity and cholinergic hypersensitivity whereas allergic asthma was singularly associated with excessive alpha-adrenergic responsiveness. Autoantibodies against beta-receptors were found predominantly in subjects with beta-adrenergic hyporeactivity. The presence of these autoantibodies and the physiologic abnormalities associated with their presence suggests a causitive relationship.

Adult↗
PubMed1993

Chemical mediators of autonomic nervous system activity.

Several modifications have improved the sensitivity and specificity of neurochemical tests to diagnose and distinguish multiple system atrophy and pure autonomic failure. These include [3H]-norepinephrine infusion to estimate plasma norepinephrine clearance; neuroendocrine stimulation tests; and simultaneous measurements of levels of levodopa, catecholamines, and catecholamine metabolites. New clinical imaging approaches have the potential to visualize alterations in neurotransmitter function in the brain and periphery. Patients with multiple system atrophy have decreased striatal radioactivity after injection of positron-emitting ligands at dopamine receptors or uptake sites, and patients with diffuse sympathetic denervation have decreased myocardial radioactivity after injection of radioactive sympathoneural imaging agents.

Autonomic Nervous System↗
PubMed1990

The autonomic nervous system is not a purely efferent system.

The concept of the autonomic nervous system as purely efferent does not seem to describe satisfactorily the patterns of its actions and mobilizing mechanisms. It is herein suggested that the autonomic nervous system should be rather considered as composed of functional modules comprising the visceral afferents, the integrating centers and the visceral efferents (sympathetic and parasympathetic).

Afferent Pathways↗
PubMed1986

[The autonomic nervous system and its role in pathology].

The autonomic nervous system under conditions of the dominant effect of the cerebral cortex is the main regulator of all physiological processes in the body. Anatomically and physiologically it is connected with the limbico-reticular complex receiving from it stimulating and correcting effects under normal conditions and variable adverse effects under pathological conditions. There are great discrepancies in physicians' opinions concerning many types of disorders of vegetative innervation which leads to the prescription of different methods of treatment poorly effective or totally unjustified. Administration of drugs to patients with vegetative disorders should be based on their effect on definite impairments of adren- and cholinergic structures with attendant dismetabolic processes and other dysfunctions.

Autonomic Nervous System↗
PubMed1994

Predominant symptoms in irritable bowel syndrome correlate with specific autonomic nervous system abnormalities.

BACKGROUND/AIMS: Irritable bowel syndrome may be influenced by the autonomic nervous system. Abnormalities in autonomic function, colon transit time, and psychological profiles in 21 patients were assessed. METHODS: Using modified Manning criteria for irritable bowel syndrome, patients were classified as constipation-predominant or diarrhea-predominant. Autonomic function was determined by one vagal cholinergic and two sympathetic adrenergic measures. Colon transit was assessed by radiopaque markers, and psychological profiles were determined by three inventories. RESULTS: Autonomic function tests showed that diarrhea-predominant subgroup values for one sympathetic adrenergic measure (postural adjustment ratio) were significantly different from controls (P < 0.01). Constipation-predominant subgroup values were significantly lower for the vagal cholinergic measure R-R interval (P < 0.05). Colon transit measures differed by subgroup in left, right, rectosigmoid, and total colon transit times. Both subgroups differed significantly from controls on psychological measures; the constipation subgroup showed more psychological distress. CONCLUSIONS: Irritable bowel syndrome specific-symptom subgroups had different patterns of autonomic functioning, colonic transit, and psychological measures. The constipation subgroup is associated with a cholinergic abnormality and the diarrhea-predominant subgroup with an adrenergic abnormality. These findings suggest specific associations between the autonomic nervous system, predominant physical symptoms, colon transit time, and psychological factors in patients with irritable bowel syndrome.

Adult↗
PubMed1993

Hemodynamic and autonomic nervous system responses to mixed meal ingestion in healthy young and old subjects and dysautonomic patients with postprandial hypotension.

BACKGROUND: Although postprandial hypotension is a common cause of falls and syncope in elderly persons and in patients with autonomic insufficiency, the pathophysiology of this disorder remains unknown. METHODS AND RESULTS: We examined the hemodynamic, splanchnic blood pool, plasma norepinephrine (NE), and heart rate (HR) power spectra responses to a standardized 400-kcal mixed meal in 11 healthy young (age, 26 +/- 5 years) and nine healthy elderly (age, 80 +/- 5 years) subjects and 10 dysautonomic patients with symptomatic postprandial hypotension (age, 65 +/- 16 years). Cardiac and splanchnic blood pools were determined noninvasively by radionuclide scans, and forearm vascular resistance was determined using venous occlusion plethysmography. In healthy young and old subjects, splanchnic blood volume increased, but supine blood pressure remained unchanged after the meal. In both groups, HR increased and systemic vascular resistance remained stable. Forearm vascular resistance and cardiac index increased after the meal in elderly subjects, whereas these responses were highly variable and of smaller magnitude in the young. Young subjects demonstrated postprandial increases in low-frequency HR spectral power, representing cardiac sympatho-excitation, but plasma NE remained unchanged. In elderly subjects, plasma NE increased after the meal but without changes in the HR power spectrum. Patients with dysautonomia had a large postprandial decline in blood pressure associated with no change in forearm vascular resistance, a fall in systemic vascular resistance, and reduction in left ventricular end diastolic volume index. HR increased in these patients but without changes in plasma NE or the HR power spectrum. CONCLUSIONS: 1) In healthy elderly subjects, the maintenance of blood pressure homeostasis after food ingestion is associated with an increase in HR, forearm vascular resistance, cardiac index, and plasma NE. In both young and old, systemic vascular resistance is maintained. 2) Dysautonomic patients with postprandial hypotension fail to maintain systemic vascular resistance after a meal. This impairment in vascular response to meal ingestion may underlie the development of postprandial hypotension. 3) The measurement of mean HR or plasma NE does not adequately characterize autonomic cardiac control. Power spectral analysis suggests an impairment in the postprandial autonomic modulation of HR in healthy elderly and dysautonomic subjects, possibly predisposing to hypotension when vascular compensation is inadequate.

Adult↗
PubMed2002

Dysautonomias: clinical disorders of the autonomic nervous system.

The term dysautonomia refers to a change in autonomic nervous system function that adversely affects health. The changes range from transient, occasional episodes of neurally mediated hypotension to progressive neurodegenerative diseases; from disorders in which altered autonomic function plays a primary pathophysiologic role to disorders in which it worsens an independent pathologic state; and from mechanistically straightforward to mysterious and controversial entities. In chronic autonomic failure (pure autonomic failure, multiple system atrophy, or autonomic failure in Parkinson disease), orthostatic hypotension reflects sympathetic neurocirculatory failure from sympathetic denervation or deranged reflexive regulation of sympathetic outflows. Chronic orthostatic intolerance associated with postural tachycardia can arise from cardiac sympathetic activation after "patchy" autonomic impairment or blood volume depletion or, as highlighted in this discussion, from a primary abnormality that augments delivery of the sympathetic neurotransmitter norepinephrine to its receptors in the heart. Increased sympathetic nerve traffic to the heart and kidneys seems to occur as essential hypertension develops. Acute panic can evoke coronary spasm that is associated with sympathoneural and adrenomedullary excitation. In congestive heart failure, compensatory cardiac sympathetic activation may chronically worsen myocardial function, which rationalizes treatment with beta-adrenoceptor blockers. A high frequency of positive results on tilt-table testing has confirmed an association between the chronic fatigue syndrome and orthostatic intolerance; however, treatment with the salt-retaining steroid fludrocortisone, which is usually beneficial in primary chronic autonomic failure, does not seem to be beneficial in the chronic fatigue syndrome. Dysautonomias are an important subject in clinical neurocardiology.

Autonomic Nervous System↗
PubMed2002

Modulation of QT interval during autonomic nervous system blockade in humans.

BACKGROUND: It is thought that the autonomic nervous system modulates QT interval, but traditional autonomic blockade combining propranolol and atropine has produced conflicting results. We used the alternative approach of interrupting neurotransmission at the level of autonomic ganglia to determine its effect on the QT interval. METHODS AND RESULTS: We infused trimethaphan at increasing doses (0.5 to 10 mg/min IV) while monitoring heart rate, heart rate variability spectra, QT interval, and blood pressure in 10 normal volunteers, 9 patients with multiple system atrophy (MSA), and 8 patients with pure autonomic failure (PAF). The QT interval was corrected for heart rate using Bazett's formula (QTc). Patients with PAF had very low heart rate variability and a prolonged QTc at baseline (465+/-8 ms) compared with patients with MSA (448+/-6 ms) and normal subjects (432+/-6 ms). In normal subjects, trimethaphan dose-dependently prolonged QTc (to 469+/-7 ms), decreased RR interval (995+/-45 to 670+/-35 ms), and abolished heart rate variability. In MSA patients, trimethaphan also prolonged QTc (to 463+/-7 ms) and reduced heart rate variability but did not significantly change RR interval (from 813+/-38 to 801+/-39). CONCLUSIONS: Autonomic blockade prolongs QT interval in normal subjects to a similar duration as in PAF patients. Furthermore, blocking residual autonomic tone in PAF patients is associated with a further increase in QT interval length. Patients with MSA have greater residual sympathetic tone and greater prolongation of the QT interval during ganglionic blockade than PAF patients.

Aged↗