Abstract
Basic autonomic nervous function was evaluated in patients with neurocardiogenic syncope (NCS). Atropine, isoproterenol, propranolol, phenylephrine, and phentolamine were administered successively, and parasympathetic nerve activity and beta- (and alpha-) activity, sensitivity, and secretion of the sympathetic nerve were determined in patients with NCS and control subjects. In patients with NCS, beta- and alpha- sensitivity were higher and beta-activity and beta- and alpha-secretion lower than in control subjects. In patients with NCS, the increased basic beta-sensitivity may contribute to induce strong cardiac contractions and augment ventricular mechanoreceptor response, and a compensatory state against diminished neuronal sympathetic activity is suggested by the increased alpha-sensitivity.
MeSH terms
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Adolescent
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Adrenergic alpha-Agonists / administration & dosage
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Adrenergic alpha-Antagonists / administration & dosage
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Adrenergic beta-Agonists / administration & dosage
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Adrenergic beta-Antagonists / administration & dosage
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Adult
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Atropine / administration & dosage
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Blood Pressure / drug effects
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Blood Pressure / physiology
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Female
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Heart Rate / drug effects
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Heart Rate / physiology
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Humans
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Infusions, Intravenous
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Isoproterenol / administration & dosage
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Male
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Middle Aged
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Parasympathetic Nervous System / drug effects
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Parasympathetic Nervous System / physiopathology*
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Parasympatholytics / administration & dosage
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Phentolamine / administration & dosage
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Phenylephrine / administration & dosage
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Propranolol / administration & dosage
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Severity of Illness Index
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Sympathetic Nervous System / drug effects
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Sympathetic Nervous System / physiopathology*
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Syncope, Vasovagal / blood
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Syncope, Vasovagal / diagnosis
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Syncope, Vasovagal / physiopathology*
Substances
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Adrenergic alpha-Agonists
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Adrenergic alpha-Antagonists
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Adrenergic beta-Agonists
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Adrenergic beta-Antagonists
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Parasympatholytics
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Phenylephrine
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Atropine
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Propranolol
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Isoproterenol
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Phentolamine