MATURATION OF SYMPATHETIC NEUROTRANSMISSION IN THE RAT-HEART .7. SUPPRESSION OF SYMPATHETIC RESPONSES BY DEXAMETHASONE
- 1 January 1981
- journal article
- research article
- Vol. 216 (1), 6-11
Abstract
Effects of dexamethasone on development of sympathetic nerve function in the heart were evaluated by giving 1 mg/kg of dexamethasone s.c. daily for several days beginning the day after birth. Dexamethasone interfered with tyramine- and isoproterenol-induced tachycardia in the neonates but did not cause alterations in development of a marker for presynaptic sympathetic nerve terminals (synaptic vesicle uptake of [3H]norepinephrine) nor of postsynaptic .beta. adrenoceptor binding of [3H]dihydroalprenolol; the deficit was unrelated to general cellular effects of the hormone. The subnormal chronotropic responses of the heart to sympathetic stimulation in dexamethasone-treated neonatal rats apparently result from uncoupling of receptors from the organ response. The effects of dexamethasone on cardiac responses were specific to the neonate, as mature rats given dexamethasone did not show suppression of cardiac sympathetic action. Neonatal dexamethasone treatment produced a deficit of adrenomedullary development with deficiencies in catecholamine levels and in catecholamine biosynthetic enzymes; deficits in phenylethanolamine N-methyltransferase activity persisted into young adulthood.This publication has 12 references indexed in Scilit:
- Ornithine decarboxylase as a tool in developmental neurobiologyLife Sciences, 1979
- SYNAPTIC VESICLES ISOLATED FROM RAT HEART:l‐[3H]NOREPINEPHRINE UPTAKE PROPERTIES1Journal of Neurochemistry, 1979
- ACCELERATED DEVELOPMENT OF RAT SYMPATHETIC NEUROTRANSMISSION CAUSED BY NEONATAL TRIIODOTHYRONINE ADMINISTRATION1979
- RESPONSES OF HEART ORNITHINE DECARBOXYLASE AND ADRENAL CATECHOLAMINES TO METHADONE AND SYMPATHETIC STIMULANTS IN DEVELOPING AND ADULT RATS1978
- Thyroid hormone regulation of beta-adrenergic receptor number.Journal of Biological Chemistry, 1977
- IMPAIRED MATURATION OF PRE-SYNAPTIC CHOLINERGIC NERVE TERMINALS IN THE SUPERIOR CERVICAL GANGLIA AFTER ADMINISTRATION OF GUANETHIDINE AND DEXAMETHASONEThe Japanese Journal of Pharmacology, 1977
- Inhibition of Enzymatic Synthesis of Epinephrine by Low Doses of GlucocorticoidsEndocrinology, 1967
- Control of Enzymatic Synthesis of Adrenaline in the Adrenal Medulla by Adrenal Cortical SteroidsJournal of Biological Chemistry, 1966
- 3,4-DIHYDROXYPHENYLETHYLAMINE BETA-HYDROXYLASE - PHYSICAL PROPERTIES COPPER CONTENT AND ROLE OF COPPER IN CATALYTIC ACTIVITY1965
- Cardiac Necrosis Accompanying Potassium Deficiency and Administration of CorticosteroidsCirculation Research, 1963