Factors influencing neurohumoral control of the heart in the newborn dog
| Autor: | WP Geis, WF Friedman, DV Priola, CJ Tatooles |
|---|---|
| Rok vydání: | 1975 |
| Předmět: |
medicine.medical_specialty
Stellate Ganglion Tyramine Blood Pressure Stimulation Vagotomy Norepinephrine (medication) Norepinephrine chemistry.chemical_compound Catecholamines Dogs Heart Rate Physiology (medical) Internal medicine Adrenal Glands Heart rate Animals Medicine Vagal tone Ligation business.industry Chloralose Myocardium Isoproterenol Carotid sinus Adrenalectomy Heart Vagus Nerve Electric Stimulation Vagus nerve Carotid Sinus medicine.anatomical_structure Endocrinology Animals Newborn chemistry Catecholamine business medicine.drug |
| Zdroj: | American Journal of Physiology-Legacy Content. 228:1685-1689 |
| ISSN: | 0002-9513 |
| DOI: | 10.1152/ajplegacy.1975.228.6.1685 |
| Popis: | Several investigators have documented immaturity of cardiac autonomic innervation in neonates. To evaluate the integrity of afferent and efferent responses and to determine the role of circulating catecholamines in newborns, 50 puppies and 24 adult dogswere studied with the use of chloralose anesthesia. Interventions were: bilateralvagotomy, bilateral carotid occlusion, central vagus stimulation, stellate stimulation, bilateral adrenalectomy, infusion of norepinephrine or isoproterenol, and intravenoustyramine. Newborns exhibited supersensitivity to exogenous norepinephrine, isoproterenol, and stellate stimulation; responses to carotid occlusion and central vagal stimulation were comparable in both groups. Newborns had less resting vagal tone. After adrenalectomy, newborns exhibited a more marked decline in systemic pressureand heart compared to adults. Myocardial catecholamine content in newborns was 1/10 that in adults, whereas plasma catecholamine concentration in newborns was 30-fold greater than in adults. These data demonstrate functional integrity of afferent and efferent cardiac autonomic pathways in the newborn, define in vivo supersensitivity to the sympathetic neurotransmitter, and suggest a dominant role of circulating catecholamines in modulation of cardiovascular events in neonates. |
| Databáze: | OpenAIRE |
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