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Opposite effects on hippocampal corticosteroid receptors induced by stimulation of beta and alpha 1 noradrenergic receptors.
- Source :
-
Neuroscience [Neuroscience] 1995 Jun; Vol. 66 (3), pp. 539-45. - Publication Year :
- 1995
-
Abstract
- Central corticosteroid receptors play an important role in the regulation of the secretion of corticosterone. Although these receptors are thought to be regulated by circulating levels of corticosterone, there is evidence for direct neural control. For example, it has been shown that noradrenergic lesions can both increase and decrease corticosteroid receptors depending on the brain structure involved. In the present study, we investigated the role of different noradrenergic receptors in the rat, by examining the effect of the acute administration of agonists and antagonists of beta and alpha 1 noradrenergic receptors on hippocampal type I and type II corticosteroid receptor levels. The effects of these drugs were studied in adrenalectomized animals whose plasma levels of corticosterone were maintained in the physiological range by implantation of coritcosterone pellets. Our results show that the beta receptor agonist salbutamol (5 mg/kg) increased the number of type I and type II hippocampal corticosteroid receptors. This effect was blocked by the beta receptor antagonist propranolol (5 mg/kg), which had no effect on its own. In contrast, the alpha 1 receptor agonist phenylephrine (100 micrograms) reduced the number of type I and type II corticosteroid receptors, whereas the alpha 1 receptor antagonist prazosin (0.5 mg/kg) increased type I receptors. The effect of prazosin was attributed to an increase in the relative beta tonus resulting from blockade of alpha 1 receptors. Its effect was reversed by the simultaneous injection of the beta receptor antagonist propranolol. In conclusion, our results show that noradrenergic transmission can have both a facilitatory and an inhibitory action on central corticosteroid receptors by acting respectively on beta and alpha 1 noradrenergic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
- Subjects :
- Albuterol administration & dosage
Albuterol pharmacology
Animals
Cerebral Ventricles drug effects
Hippocampus drug effects
Injections, Intraventricular
Kinetics
Male
Microinjections
Phenylephrine administration & dosage
Phenylephrine pharmacology
Prazosin administration & dosage
Prazosin pharmacology
Propranolol administration & dosage
Propranolol pharmacology
Rats
Rats, Sprague-Dawley
Receptors, Adrenergic, alpha-1 drug effects
Receptors, Adrenergic, beta drug effects
Receptors, Steroid drug effects
Cerebral Ventricles physiology
Hippocampus metabolism
Receptors, Adrenergic, alpha-1 physiology
Receptors, Adrenergic, beta physiology
Receptors, Steroid biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 0306-4522
- Volume :
- 66
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 7644018
- Full Text :
- https://doi.org/10.1016/0306-4522(94)00620-k