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The role of cardiac metaiodobenzylguanidine uptake in the differential diagnosis of parkinsonian syndromes.

Scintigraphy with radiolabeled metaiodobenzylguanidine (MIBG) enables the visualization and quantification of functionally intact adrenergic neurons and cells. In Parkinson disease, MIBG uptake of postganglionic cardiac sympathetic neurons is grossly reduced at an early stage of the disease in almost all patients with a clinical severity score of Hoehn and Yahr II or higher. Based on the meta-analysis of studies with a total of 246 cases of Parkinson disease and 45 cases of multiple system atrophy, the overall sensitivity to positively identify patients with Parkinson disease was 89.7%, and the specificity to discriminate them from patients with multiple system atrophy was 94.6%. Quantification of cardiac MIBG uptake is a valuable tool to identify patients with Parkinson disease and to discriminate them from other neurodegenerative disorders early in the course of the disease.

3-Iodobenzylguanidine↗

Starnberg trial on epidemiology of Parkinsonism and hypertension in the elderly. Prevalence of Parkinson's disease and related disorders assessed by a door-to-door survey of inhabitants older than 65 years.

OBJECTIVE: To investigate the prevalence of different types of parkinsonism (PS) in the elderly, regardless of health care service or drug prescription, by a door-to-door survey in two German villages. DESIGN: We investigated the prevalence of PS in a rural Bavarian population of individuals older than 65 years (982 participants; response rate, 82.5%) using a door-to-door-survey and a biphasic approach. MAIN OUTCOME MEASURES: Two investigators employed a pretest screening questionnaire and motor tests for signs of PS. Individuals suspected of suffering from PS were reinvestigated by two neurologists trained in movement disorders, and computed tomographic scans were performed. RESULTS: The prevalence of Parkinson's disease in individuals older than 65 years was 0.71% (95% confidence interval, 0.19% to 1.23%), with a male predominance (five men, two women). Parkinsonism of other pathogenesis included drug-induced PS (0.41%, four of 982 inhabitants), vascular PS (0.20%, two of 982), multiple system atrophy (0.31%, three of 982), and Fahr's disease (0.10%, one of 982). The high prevalence of normal-pressure hydrocephalus (0.41%, four of 982 inhabitants) was an unexpected finding that was confirmed by computed tomography. Fifty percent of cases of PS were newly diagnosed. CONCLUSIONS: This study represents the first door-to-door survey on PS in Germany. In addition, for the first time, it includes a clinical differentiation between Parkinson's disease, multiple system atrophy (of the striatonigral type), and PS of other pathogenesis. The prevalence of Parkinson's disease corresponds to that reported in other surveys of people older than 65 years. Normal-pressure hydrocephalus and multiple system atrophy, on the other hand, were more prevalent than expected, and all these cases were newly diagnosed.

Adult↗

Effect of the somatostatin analogue SMS-201-995 on the adrenergic response to glucose ingestion in patients with postprandial hypotension.

PURPOSE: The somatostatin analogue SMS-201-995 has recently been introduced as a new therapy for postprandial hypotension in patients with autonomic neuropathy. The present study was performed to determine the effect of SMS-201-995 on the adrenergic response to glucose ingestion in patients with this disorder. PATIENTS AND METHODS: Eleven patients with postprandial hypotension were studied: six with central autonomic dysfunction (multiple system atrophy) and five with peripheral sympathetic dysfunction (progressive autonomic failure). Patients received either a subcutaneous injection of SMS-201-995 or a placebo injection, immediately before administration of a 50-g glucose drink. Each treatment was given on separate, consecutive days in a randomized fashion. RESULTS: Glucose ingestion caused a decrease in blood pressure (from 82 +/- 6 mm Hg to 66 +/- 7 mm Hg, p less than 0.01) and an increase in plasma norepinephrine level (165 +/- 20 pg/mL to 305 +/- 85 pg/mL, p less than 0.01) in five patients with progressive autonomic failure. Administration of SMS-201-995 prevented both the decline in blood pressure and the increase in norepinephrine. By contrast, glucose ingestion elicited no increase in plasma norepinephrine levels despite profound hypotension (average postprandial mean blood pressure, 55 +/- 3 mm Hg) in six patients with multiple system atrophy. Administration of SMS-201-995 prevented postprandial hypotension in these patients, but had no effect on plasma norepinephrine. CONCLUSION: Our data indicate that the pressor effect of SMS-201-995 is independent of the sympathetic nervous system in patients with multiple system atrophy, but may suppress the adrenergic response to glucose ingestion in patients with progressive autonomic failure.

Autonomic Nervous System Diseases↗

Alpha-synuclein in familial Alzheimer disease: epitope mapping parallels dementia with Lewy bodies and Parkinson disease.

BACKGROUND: Alpha-synuclein is a major component of Lewy bodies (LBs) in Parkinson disease and dementia with LBs and of glial cytoplasmic inclusions in multiple system atrophy. However, epitope mapping for alpha-synuclein is distinctive in different neurodegenerative diseases. The reasons for this are poorly understood but may reflect fundamental differences in disease mechanisms. OBJECTIVE: To investigate the alpha-synuclein epitope mapping properties of LBs in familial Alzheimer disease. DESIGN AND SETTING: We compared LBs in familial Alzheimer disease with those in synucleinopathies by probing 6 brains of persons with familial Alzheimer disease using a panel of antibodies to epitopes spanning the alpha-synuclein protein. Results were compared with data from brains of persons with Parkinson disease, dementia with LBs, and multiple system atrophy. RESULTS: The brains of persons with familial Alzheimer disease showed consistent staining of LBs with all antibodies, similar to Parkinson disease and dementia with LBs but different from alpha-synuclein aggregates that occurred in multiple system atrophy. CONCLUSIONS: These data suggest that the epitope profiles of alpha-synuclein in LBs are similar, regardless of whether the biological trigger is related to synuclein or a different genetic pathway. These findings support the hypothesis that the mechanism of alpha-synuclein aggregation is the same within cell types but distinctive between cell types.

Aged↗

Cognitive dysfunction and impaired organization of complex motility in degenerative parkinsonian syndromes.

BACKGROUND: A frontostriatal pattern of cognitive decline, consisting of a frontal lobe-like syndrome without genuine cortical defects such as amnesia, apraxia, aphasia, or agnosia, is well established in basal ganglial diseases. Recent pathological investigations, however, have again noted cortical damage in progressive supranuclear palsy (PSP), suggesting that cortical defects could be present. OBJECTIVES: To delineate the pattern of cognitive impairment and to detect higher-order motor impairments (including ideomotor apraxia) in parkinsonian syndromes. PATIENTS AND METHODS: We assessed ideomotor apraxia, and simple and sequential tapping in patients with Parkinson disease, multiple system atrophy, and PSP with similar disease severity, age range, and education. We also administered a comprehensive battery of neuropsychological tests to examine general intelligence, memory, executive functions, attention, and visuospatial orientation. The results were compared between groups and with a matched normal control group. RESULTS: Sequential tapping and the imitation of sequences of gestures were impaired in all patient groups, with patients with PSP performing worse than the other groups. Based on ideomotor apraxia scores and a qualitative analysis of errors, 3 patients with PSP and 2 with multiple system atrophy were considered apraxic. General intelligence and executive functions were compromised in all patient groups. The impairment of patients with PSP was more pervasive than that of the other groups, and included compromise of visuospatial functions, attention, and memory. Discriminant analysis of all cognitive and motor tests showed that the tapping and ideomotor apraxia tests best identified the patients vs control subjects. CONCLUSIONS: The presence of cortical as well as subcortical damage in patients with PSP and those with multiple system atrophy is indicated by the presence of pervasive cognitive and motor disturbances in the former, substantial motor disorganization in the latter, and the finding of ideomotor apraxia in some patients with these diseases. Furthermore, the discovery that tests of motor and gesture best identified all patients vs control subjects is consistent with the existence of a common motor disorganization in these parkinsonian syndromes, in agreement with the known damage to the corticostriatal pathways in these conditions.

Aged↗

Orthostatic hypotension in de novo Parkinson disease.

BACKGROUND: It is accepted that orthostatic hypotension is a clinical marker for the diagnosis of multiple system atrophy, but conflicting data indicate that it may also be present in Parkinson disease (PD). OBJECTIVES: To evaluate the prevalence of autonomic cardiovascular impairment and orthostatic hypotension in a large group of patients with de novo PD, followed up for at least 7 years, to clinically confirm the diagnosis of the disease. METHODS: During a 2-year recruiting period, 60 untreated patients diagnosed as having idiopathic PD underwent autonomic cardiovascular function evaluation using the Ewing test. Patients subsequently received dopaminergic therapy and their condition was followed up for at least 7 years. RESULTS: Nine (15%) of 60 patients were excluded from the study because during the follow-up period a parkinsonian syndrome was diagnosed (5 had multiple system atrophy and 4 had progressive supranuclear palsy). Data from 51 patients with PD underwent final statistical analysis and the results were compared with those of 51 age-matched healthy control subjects who had taken the same battery of autonomic tests. A statistically significant difference was found in postural hypotension (P =.02) and deep breathing test results (P =.03) between patients and controls. Seven (14%) of 51 patients with PD and 3 (60%) of 5 patients with multiple system atrophy had a decrease of more than 20 mm Hg in systolic blood pressure on standing. CONCLUSIONS: Data from this study indicate a high prevalence of sympathetic and parasympathetic failure in patients with de novo PD, and when using a decrease of at least 20 mm Hg in systolic blood pressure, manometric orthostatic hypotension was found in 7 (14%) of the 51 patients with de novo PD.

Autonomic Nervous System↗

Studies on neurotransmitter markers and neuronal cell density in the cerebellar system in olivopontocerebellar atrophy and cortical cerebellar atrophy.

Glutamate, aspartate and gamma-aminobutyrate (GABA) concentrations and choline acetyltransferase (ChAT) activity were measured in postmortem cerebellar cortical areas and brainstem nuclei of 10 normal controls, 5 patients of olivopontocerebellar atrophy (OPCA) with multiple system atrophy (MSA) and 2 patients of cortical cerebellar atrophy (CCA). In addition, the neuronal cell density in the cerebellar cortex and the brainstem nuclei was determined, and the correlation between neurotransmitter markers and the neuronal cell densities were investigated. Glutamate and aspartate concentrations in the cerebellar cortical tissues were markedly varied from case to case of MSA (OPCA) and CCA patients. However, glutamate concentration in the anterior vermis showed a positive correlation coefficient with the density of granule cells (r = 0.554, 0.05 less than P less than 0.10) and, those in the posterior vermis and in the cerebellar hemisphere were positively correlated with cells in the inferior olive (r = 0.707 and 0.607, P less than 0.05, respectively). Aspartate concentration in the anterior vermis also has a positive correlation coefficient (r = 0.571, 0.05 less than P less than 0.10) with the density of cells in the inferior olive. GABA concentrations in the dentate nucleus were decreased in all cases of MSA (OPCA) and CCA, and were positively correlated with the degree of loss of Purkinje cells (r = 0.765, P less than 0.01). ChAT activities were decreased in certain cases of MSA (OPCA), but conversely, increased in CCA patients. ChAT activity in the posterior vermis has a positive correlation coefficient (r = 0.613, 0.05 less than P0.10) with the cell density in the pontine nucleus. A possibility of a compensatory increase of ChAT activity in CCA patients was discussed.

Adult↗

Ubiquitination of alpha-synuclein is not required for formation of pathological inclusions in alpha-synucleinopathies.

alpha-Synucleinopathies, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, are neurodegenerative disorders in which abnormal inclusions containing alpha-synuclein accumulate in selectively vulnerable neurons and glia. In this report, immunohistochemistry demonstrates ubiquitin in subsets of alpha-synuclein inclusions in dementia with Lewy bodies and multiple system atrophy. Biochemistry demonstrates that alpha-synuclein in the sodium dodecyl sulfate-soluble fractions of diseased brains is ubiquitinated, with mono- and di-ubiquitinated species predominating over polyubiquitinated forms. Similar immunohistochemical and biochemical characteristics were observed in an A53T mutant human alpha-synuclein transgenic mouse model of neurodegenerative alpha-synucleinopathies. Furthermore, in vitro ubiquitination of alpha-synuclein fibrils recapitulated the pattern of alpha-synuclein ubiquitination observed in human disease and the A53T alpha-synuclein mouse model. These results suggest that ubiquitination of alpha-synuclein is not required for inclusion formation and follows the fibrillization of alpha-synuclein.

Adult↗

Osmosensitive mechanisms contribute to the water drinking-induced pressor response in humans.

BACKGROUND: Water drinking elicits a sympathetically mediated pressor response in multiple-system atrophy patients through an unknown mechanism. We reasoned that gastrointestinal distention, hyposomotic stimulation, or both contribute to the water-induced pressor response. METHODS: We compared the response to normal saline and water on blood pressure in 10 patients with probable multiple-system atrophy. Patients featured moderate to severe autonomic dysfunction. EKG and finger arterial blood pressure were recorded continuously, and 500 mL normal saline and distilled water were each given in a single-blinded fashion. Fluids were applied through a previously inserted nasogastric tube within a 5-minute period. RESULTS: Blood pressure began to increase within 10 minutes after water administration and reached a maximum after 20 minutes. Blood pressure did not change after saline administration. The blood pressure change after 20 minutes was 8 +/- 9/2 +/- 5 mmHg with water and -1 +/- 11/-1 +/- 7 mmHg with normal saline administration (p = 0.02 between interventions). Heart rate did not change with either intervention. CONCLUSION: Ingestion of water elicits a greater pressor response than the ingestion of normal saline. Thus, gastric distention is probably not the crucial mechanisms for the water-induced pressor response. Instead, the response may be mediated through osmosensitive afferent structures in the gastrointestinal tract, portal vein, and liver.

Autonomic Nervous System Diseases↗

Gliomatosis cerebri may present as an atypical parkinsonian syndrome.

An 85-year-old man presented with 3 years of a progressive akinetic rigid syndrome with ataxia, falls, levodopa unresponsiveness, and autonomic dysfunction. Early in the course of illness, cranial magnetic resonance imaging (MRI) was thought to show pontine enlargement but later was reinterpreted by experts as normal. Two subsequent cranial MRIs were believed to show only mild atrophy. An initial clinical diagnosis of multiple system atrophy was made. The patient died 4 years after the onset of symptoms. Pathological examination revealed diffuse infiltration of multiple brain regions with cells of astrocytic and microglial origin consistent with a diagnosis of gliomatosis cerebri.

Aged↗

Attention and cognition in bradykinetic-rigid syndromes: an event-related potential study.

Bradykinetic-rigid syndromes are often accompanied by cognitive impairment. Because prominent motor involvement in these disorders may interfere with neuropsychological testing, we used event-related potentials (ERPs) for the assessment of cognition and attention in 41 patients with various bradykinetic-rigid syndromes of less than 5 years duration: idiopathic Parkinson's disease corticobasal degeneration, Steele-Richardson-Olszewski syndrome (SRO), and multiple system atrophy. Patients were compared with matched normals. ERP abnormalities in the auditory "oddball" paradigm were found only in corticobasal degeneration and SRO. ERP abnormalities in selective attention tasks were present in all patient groups, changes in SRO being the most prevalent. Abnormalities in corticobasal degeneration were present under "less-attention-demanding" conditions and suggested involvement of posterior parts of the brain. Multiple system atrophy and idiopathic Parkinson's disease patient groups had minimal ERP abnormalities. However, reaction times in MSA were longer in all paradigms. The results of the study support the view that bradykinetic-rigid syndromes involve some attentional deficits, but also have distinct reaction time and ERP characteristics, which may be helpful in differential diagnosis.

Acoustic Stimulation↗

Oligodendrocytes from neural stem cells express alpha-synuclein: increased numbers from presenilin 1 deficient mice.

alpha-Synuclein normally a synaptic vesicle-associated cytoplasmic protein is the major component of filamentous inclusions of neurons in Parkinson's disease and dementia with Lewy bodies. It is also the major component of glial inclusions of multiple system atrophy. In characterizing cells derived from embryonic neural stem cells we found all oligodendrocytes had strong cytoplasmic expression of alpha-synuclein. Comparison of cells from presenilin 1 (PS1)-deficient mice with wild type revealed a 7-fold increase in oligodendrocytes. Western blotting analysis indicated the cells contained alpha-synuclein monomers and SDS-stable dimers and trimers. This cell system of oligodendroglial alpha-synuclein expression is a useful system to study alpha-synuclein metabolism in the cell type affected in multiple system atrophy. Increased oligodendroglial cell numbers from PS1-deficient cells provides further evidence for a role of PS1-dependent Notch signalling in cell fate decisions.

Animals↗

Baroreflex buffering and susceptibility to vasoactive drugs.

BACKGROUND: The overall effect of vasoactive drugs on blood pressure is determined by a combination of the direct effect on vascular tone and an indirect baroreflex-mediated effect, a baroreflex buffering of blood pressure. Differences in baroreflex function affect the responsiveness to vasoactive medications, particularly baroreflex buffering of blood pressure; however, the magnitude is not known. METHODS AND RESULTS: We characterized baroreflex function and responses to vasoactive drugs in patients with idiopathic orthostatic intolerance, patients with essential hypertension, patients with monogenic hypertension and brachydactyly, patients with multiple system atrophy, and control subjects. We used phenylephrine sensitivity during ganglionic blockade as a measure of baroreflex buffering. Phenylephrine (25 microg) increased systolic blood pressure 6+/-1.6 mm Hg in control subjects, 6+/-1.1 mm Hg in orthostatic intolerance patients, 18+/-3.9 mm Hg in patients with essential hypertension, 31+/-3.4 mm Hg in patients with monogenic hypertension, and 25+/-3.4 mm Hg in patients with multiple system atrophy. Similar differences in sensitivities between groups were observed with nitroprusside. The sensitivity to vasoactive drugs was highly correlated with baroreflex buffering function and to a lesser degree with baroreflex control of heart rate. In control subjects, sensitivities to nitroprusside and phenylephrine infusions were correlated with baroreflex heart rate control and sympathetic nerve traffic. CONCLUSIONS: Our findings are consistent with an important effect of baroreflex blood pressure buffering on the sensitivity to vasoactive drugs. They suggest that even moderate changes in baroreflex function may have a substantial effect on the sensitivity to vasoactive medications.

Adrenergic beta-Agonists↗

Biochemical characterization of the core structure of alpha-synuclein filaments.

Intracellular filamentous aggregates comprised of alpha-synuclein such as Lewy bodies and glial cytoplasmic inclusions are the defining hallmarks of a subset of neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. We have analyzed biochemical and structural properties of alpha-synuclein filaments assembled in vitro or extracted from brains of patients with multiple system atrophy and found that both types of filaments are insoluble to detergents and partially resistant to proteinase K digestion. Immunoelectron microscopy and immunoblot analysis showed that both amino and carboxyl termini of alpha-synuclein in in vitro assembled filaments were degraded by proteinase K treatment, whereas the central portion of alpha-synuclein is resistant to proteinase K and retains filamentous structures. Protein sequencing and mass spectrometric analyses of the proteinase K-resistant, minimal fragment of 7 kDa revealed that amino acid residues 31-109 of alpha-synuclein constitute the core unit of the filaments. These observations suggest that the central half of the alpha-synuclein polypeptide, containing five tandem repeats as well as a part of the carboxyl-terminal acidic region, forms the core structure of alpha-synuclein filaments, which is coated by the amino- and carboxyl-terminal portions at the periphery.

Amino Acid Sequence↗

[A 67-year-old man with progressive disturbance of gait].

We report a 67-year-old man with progressive disturbance of gait. He was well until the spring of 1993 (62 years of the age), when he noted an onset of unsteady gait. He also noted that he started to have a difficulty in playing tennis, in which he became unable to hit the ball with his racket. He also noted parkinsonian features such as bradykinesia and loss of hand dexterity. He was treated with levodopa, which did not improve his symptoms. His MRI revealed marked atrophy of the cerebellum and the pons. The criss-cross high signal lesion was seen in the center of the pons. The third ventricle was dilated. The putamen was unremarkable. His subsequent course was complicated by easy to fall, difficulty in swallowing with episodes of aspiration pneumonia. He also developed nocturnal apneustic episodes. He was admitted to our hospital on November 15, 1998, when he was 67 years of the age. He had low grade fever and low blood pressure (98/70). He was anemic but not icteric. Tumors were palpated in his jaw, anterior chest, and in the left arm. He was alert but unable to convey his desire because of dyspnea and tracheostomy. His gaze was slightly restricted in the horizontal direction and markedly so in the vertical direction. Motor functions were difficult to evaluate. His clinical course was complicated by atelectasis of the right lung and pleural effusion. He developed marked edema and oliguria. He developed sudden bradycardia and expired on December 26, 1998. He was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had multiple system atrophy. Majority of the audience agreed with this diagnosis. Post-mortem examination revealed a lung cancer in the right lung (undifferentiated adenocarcinoma) with metastases to the liver, kidneys, lymph nodes, pericardium, pleura, skin, bone marrow, and the brain. Neuropathologic examination revealed marked atrophy of the pons and the cerebellum. The putamen showed brownish discoloration and atrophic changes. The substantia nigra showed marked neuronal loss and gliosis. Oligodendrocytic inclusion bodies (alpha-synuclein positive) were seen in the putamen, globus pallidus, substantia nigra, pontine nucleus, cerebellar white matter, internal capsule, cerebral peduncle, and the spinal cord. These findings are consistent with the pathologic diagnosis of multiple system atrophy. What was interesting to us was the presence of neurofibrillary tangles in the substantia nigra, nucleus ruber, globus pallidus, and subthalamic nucleus. Tuft-shaped astrocytes were also seen. This patient appears to be a rare example of combination of MSA and PSP.

Adenocarcinoma↗

Chronic neurodegenerative disease associated with HTLV-II infection.

Although human T-cell leukemia virus (HTLV) type I is known to cause a number of diseases, there has been no convincing evidence of pathological changes after infection with the related virus, HTLV-II. We have found an endemic focus of HTLV-II infection among members of an American Indian population in New Mexico, USA. We set out to determine the pathological consequences of HTLV-II infection in this population and identified two sisters (aged 59 and 46 years) with a disease superficially resembling the myeloneuropathy induced by HTLV-I. These women had a syndrome similar to the olivopontocerebellar atrophy variant of multiple system atrophy, and HTLV-II infection was confirmed by western blot and the polymerase chain reaction. Thus, HTLV-II may, like HTLV-I, cause a progressive neurodegenerative disease.

Ataxia↗

Positron emission tomography (PET) in Machado-Joseph disease.

Positron emission tomography studies on the regional cerebral glucose metabolism (rCMRglc) and 18F-fluorodopa (18F-Dopa) uptake were performed in 3 patients with Machado-Joseph disease (MJD), a dominantly inherited degenerative disease in the cerebellum, brainstem and basal ganglia. The rCMRglc in MJD was found to be significantly decreased in the cerebellum, brainstem, striatum and whole cerebral cortex in comparison to that in normal subjects. These results of rCMRglc were different from those for dominantly inherited olivopontocerebellar atrophy (dOPCA) or cerebellar cortical degeneration (CCD), however they were similar to those for sporadic olivopontocerebellar atrophy (sOPCA) and multiple system atrophy (MSA). The 18F-Dopa uptake in MJD was found to be significantly decreased in the putamen and relatively spared in the caudate, which was different from that of MSA. In addition, these results indicate that MJD showed a dysfunction, not only in the regions with apparent pathological involvement such as cerebellum, brainstem and nigro-striatal dopaminergic system, but also in the cerebral cortex and the striatum where no pathology could be observed using conventional morphological techniques.

Adult↗

Bound leptin and sympathetic outflow in nonobese men.

Leptin exists in a free form and a receptor-bound form. Protein-bound rather than free leptin levels may be associated with regulation of muscle sympathetic nerve activity (MSNA). We determined MSNA and bound leptin concentrations in 25 men [age, 29 +/- 6 yr, body mass index (BMI), 24 +/- 3 kg/m(2)]. Baroreflex sensitivity was measured using phenylephrine and nitroprusside infusions. We measured bound leptin in patients with central (multiple system atrophy, n = 8; age, 59 +/- 8 yr; BMI, 23 +/- 2 kg/m(2)) and peripheral autonomic failure (pure autonomic failure, n = 4; age, 71 +/- 10 yr; BMI, 25 +/- 3 kg/m(2)). MSNA was correlated with protein-bound leptin concentrations (r(2) = 0.35; P < 0.01) but not with free leptin levels (r(2) = 0.09). MSNA at baseline was 15 +/- 2 bursts x minutes(-1) in subjects with lower and 24 +/- 3 bursts x minutes(-1) in subjects with higher bound leptin concentrations (P < 0.05). Blood pressure as well as baroreflex regulation of heart rate and MSNA was similar in both groups. Phenylephrine and nitroprusside responses were similar. Patients with multiple system atrophy and autonomic failure featured similar bound leptin levels. We conclude that protein-bound rather than free leptin levels are correlated with basal sympathetic outflow in normotensive, nonobese men. This relationship cannot be explained by a direct central nervous effect of protein-bound leptin. Instead, protein-bound leptin may increase sympathetic vasomotor tone indirectly via a baroreflex mechanism.

Adult↗