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The 5,7-DHT-induced anticonflict effect is dependent on intact adrenocortical function.
1Department of Pharmacology, University of Göteborg, Sweden.
Life Sciences
|January 1, 1992
Summary
Adrenalectomy abolished the anxiolytic-like effects of low serotonin (5-HT) in rats, indicating that corticosteroids are crucial. Restoring corticosterone reinstated these effects, highlighting the role of adrenal function in anxiety regulation.
Area of Science:
- Neuroscience
- Endocrinology
- Pharmacology
Background:
- Serotonin (5-HT) depletion in rats induces anxiolytic-like effects, potentially mediated by the GABA(A)/benzodiazepine receptor complex (GABAA/BDZ-RC).
- Corticosteroids have been tentatively implicated in this observed effect.
Purpose of the Study:
- To investigate the role of adrenalectomy (ADX) in the anxiolytic-like effect of serotonin depletion.
- To determine if corticosteroids are necessary for the expression of this anxiolytic-like effect.
Main Methods:
- Rats were subjected to adrenalectomy (ADX) or sham surgery.
- Serotonin depletion was induced using 5,7-dihydroxytryptamine (5,7-DHT).
- Anxiolytic-like effects were assessed using Vogel's conflict test. Replacement therapy with corticosterone or dexamethasone was administered.
Main Results:
- ADX completely abolished the anxiolytic-like effect in 5,7-DHT-lesioned rats.
- Corticosterone replacement therapy reinstated the anxiolytic-like effect, while dexamethasone did not.
- 5,7-DHT-lesioned rats showed increased sensitivity to the barbiturate-like corticosteroid THDOC.
Conclusions:
- Intact adrenal function, likely involving brain steroid type I receptors, is essential for the anxiolytic-like effect following severe brain serotonin depletion.
- Adrenalectomy may reduce endogenous positive modulators at the GABAA/BDZ-RC, hindering the anxiolytic-like response.
- These findings support the involvement of enhanced endogenous activity at GABAA/BDZ-RC in the anxiolytic-like effects of serotonin depletion.