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Mineralocorticoid receptor–mediated enhancement of neuronal excitability and synaptic plasticity in the dentate gyrus in vivo is dependent on the β‐adrenergic activity
Author(s) -
Smriga Miroslav,
Nishiyama Nobuyoshi,
Saito Hiroshi
Publication year - 1998
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19980301)51:5<593::aid-jnr6>3.0.co;2-a
Subject(s) - dentate gyrus , endocrinology , medicine , mineralocorticoid , chemistry , synaptic plasticity , neuroscience , biology , receptor , hippocampus , glucocorticoid
The dentate gyrus neurons in the hippocampus contain a high density of both mineralocorticoid and adrenergic receptors. By in vivo extracellular recording from adrenalectomized rats we investigated the possible relationships between the two systems with regard to neuronal excitability and activity‐dependent synaptic plasticity. Pretreatment with aldosterone significantly enhanced both basal neuronal excitability and tetanically evoked synaptic plasticity in adrenalectomized, but not sham‐operated rats. The enhancement was blocked by spironolactone, indicating a mineralocorticoid receptor–dependent effect. The adrenomedullary hormone epinephrine also significantly enhanced synaptic plasticity via activation of β‐adrenergic receptors. β‐Adrenergic antagonist propranolol, infused directly into the dentate gyrus granule cell layer, significantly reduced the effect of aldosterone on neuronal excitability and partly canceled the aldosterone‐enhanced synaptic plasticity. No effect of propranolol was found after its amygdaloid infusion. The mineralocorticoid receptor antagonist spironolactone did not affect the epinephrine‐induced effects. These results indicate that the pretreated adrenal steroids interact with the catecholaminergic system in the dentate gyrus of adrenalectomized rats and that the functional β‐adrenergic pathway is involved in the mechanism of mineralocorticoid‐induced cellular effects in vivo. J. Neurosci. Res. 51:593–601, 1998. © 1998 Wiley‐Liss, Inc.