Record Display for the EPA National Library Catalog


Main Title Effects of Prenatal Dexamethasone or Terbutaline Exposure on Development of Neural and Intrinsic Control of Heart Rate.
Author Hou, Q. C. ; Slotkin, T. A. ;
CORP Author Duke Univ. Medical Center, Durham, NC. Dept. of Pharmacology.;Health Effects Research Lab., Research Triangle Park, NC.
Publisher c1989
Year Published 1989
Report Number EPA-R-813769; EPA/600/J-89/376;
Stock Number PB90-216235
Additional Subjects Heart rate ; Parasympathetic nervous system ; Sympathetic nervous system ; Graphs(Charts) ; Body weight ; Reprints ; Prenatal exposure delayed effects ; Terbutaline ; Dexamethasone ; Adrenergic beta receptor blockaders
Library Call Number Additional Info Location Last
NTIS  PB90-216235 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 6p
The study compares the effects of prenatal exposure to terbutaline (a beta-adrenergic agonist) and dexamethansone (a glucocorticoid) on the development of heart rate control mechanisms in the rat. Both drugs produced a persistent reduction in resting heart rate appearing during the 2nd postnatal wk, but by different mechanisms. Terbutaline affected the development of autonomic input from the CNS, characterized by a premature shift from sympathetic to parasympathetic dominance; thus, heart rate differences between terbutaline-exposed animals and controls resolved with acute treatment with a ganglionic blocking agent (chlorisondamine). Dexamethasone did not alter neural input to the myocardium (its actions were not reversed by ganglionic blockade), but instead reduced the intrinsic heart rate; the prenatal glucocorticoid treatment also reduced the sensitivity of the mydocardium to beta-adrenergic stimulation, a factor that could contribute to the alterations in intrinsic rate. (Copyright (c) 1989 International Pediatric Research Foundation, Inc.)