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Title: Effect of postnatal lead exposure on the development of sympathetic innervation of the heart. [Rats]

To determine possible mechanisms for this Pb-induced cardiotoxicity, several neutrochemical parameters indicative of cardiac sympathetic innervation were measured in developing rats. Presynaptic indices of nerve terminal development which were studied included steady-state levels of norepinephrine, neuronal uptake and vesicular storage of /sup 3/H-norepinephrine. Analysis of postsynaptic development was accomplished by quantitating the density of ..beta..-adrenergic receptors and by measuring the activity of adenylate cyclase. Rat pups were exposed to Pb from birth to weaning (21 days) via the milk of dams whose drinking water contained 0.2% Pb acetate. This method and level of Pb treatment had no effect on body or heart weight development, however, it did result in a seven-fold increase in the blood Pb content (70-75 ..mu..g/dl) of the treated pups during the period of exposure. Pb exposure accelerated the development of sympathetic innervation of the heart as detected by significant increases in the vesicular uptake of /sup 3/H-norepinephrine and the steady-state concentration of norepinephrine measured at postnatal day 4. On the other hand, ontogeny of the neutronal uptake of /sup 3/H-norepinephrine in the heart and in the forebrain was not affected by Pb treatment. The apparent premature development of sympathetic innervation induced by Pb treatment was notmore » reflected in significant alterations in either the density or the affinity of ..beta..-adrenergic receptor sites determined by the binding kinetics of /sup 3/H-dihydroalprenolol.« less
Authors:
Publication Date:
OSTI Identifier:
5762133
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Univ. of Texas Graduate School of Biomedical Sciences,Galveston, TX
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; LEAD; BIOLOGICAL EFFECTS; NORADRENALINE; UPTAKE; TRITIUM COMPOUNDS; ACETATES; AUTONOMIC NERVOUS SYSTEM; DRINKING WATER; HEART; MILK; NEONATES; NERVES; RATS; ADRENAL HORMONES; ANIMALS; AUTONOMIC NERVOUS SYSTEM AGENTS; BIOLOGICAL MATERIALS; BODY; BODY FLUIDS; CARBOXYLIC ACID SALTS; CARDIOTONICS; CARDIOVASCULAR AGENTS; CARDIOVASCULAR SYSTEM; DRUGS; ELEMENTS; FOOD; HORMONES; HYDROGEN COMPOUNDS; LABELLED COMPOUNDS; MAMMALS; MATERIALS; METALS; NERVOUS SYSTEM; NEUROREGULATORS; ORGANS; OXYGEN COMPOUNDS; RODENTS; STEROID HORMONES; SYMPATHOMIMETICS; VERTEBRATES; WATER 560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)