Effect of Adrenocortical Hormones on Activity of the Serotoninergic System in Limbic Structures in Rats

Abstract

A single dose of corticosterone (1 mg/kg b.w. i.p.) increased the 5-hydroxytryptamine (5-HT) content in the mesencephalon, amygdala and hypothalamus. The maximum was observed at 15 min following administration. The 5-HT level returned to normal between 60 and 180 min. The 5-hydroxyindoleacetic acid (5-HIAA) content decreased in the mesencephalon and hypothalamus at 15 min, and then increased to the maximum at 30 min in the mesencephalon and at 45 min in the hypothalamus and amygdala. There were no changes in the septum and hippocampus either in 5-HT or in 5-HIAA content following corticosterone administration. Desoxycorticosterone administration (1 mg/rat i.p.) was ineffective. Tritiated 5-HT uptake did not change in the hypothalamus and mesencephalon tissue in vitro after corticosterone or desoxycorticosterone treatment. Adrenalectomy caused a decrease in the 5-HT content in all brain areas studies. 5-HIAA decreased only in the hypothalamus. Corticosterone administration normalized the 5-HT and 5-HIAA content in the hypothalamus and mesencephalon in adrenalectomized rats. Tritiated 5-HT uptake was lower in the hypothalamus and mesencephalon in adrenalectomized rats. Corticosterone administration increased the activity back to normal in the hypothalamus, however desoxycorticosterone was ineffective. The data suggest that the plasma corticosterone level plays a role in the regulation of the activity of the serotoninergic system in certain limbic brain structures.

Production of corticotrophin releasing hormone by the isolated hypothalamus of the rat.

“…We have extended the work by studying the ability of individual hypothalami not only to release but also to synthesize CRH, and data with a greater degree of precision have been obtained using a more satisfactory assay technique (Buckingham & Hodges, 1977 (Hedge & Smelik, 1968;Abe & Hiroshige, 1974;Suzuki, Hirose, Abe & Matsumoto, 1975) the role of 5-AT is still controversial. Vermes et al (1972), Simon & George (1975) and Telegdy & Vermes (1975) claim that 5-HT inhibits CRH secretion but most of the work in laboratory animals (Krieger & Rizzo, 1969;Abe & Hiroshige, 1974;Chambers & Brown, 1976) and in man (Imura, Nakai & Yoshimi, 1973;Chihara, Kato, Maeda, Matsukura & Imura, 1976;Delitala, Masala, Alagna & Devilla, 1976) support our findings that 5-HT stimulates CRH release.…”

Mineralocorticoid and glucocorticoid receptors in the brain. Implications for ion permeability and transmitter systems

“…In agreement with this idea are reports that low corticosterone doses result within 30 min in an increase of the 5HT concentration in hypothalamic areas, midbrain and amygdala, whereas high doses produce the opposite result (Telegdy and Vermes, 1975;Kovacs et al, 1977). This dose-dependency may partly explain incongruencies in other reports, which make use of different species and design (e.g.…”

“…Green and Curzon, 1968;Hall and McGinley, 1982). Apart from these acute effects on 5HT content in the brain, long term ADX was found either not to affect 5HT concentration or induce a glucocorticoid reversible reduction of the 5HT concentration (Telegdy and Vermes, 1975;Rastogi and Singhal, 1978).…”

Regional Serotonin Metabolism under Basal and Restraint Stress Conditions in the Brain of Transgenic Mice with Impaired Glucocorticoid Receptor Function

“…Decreases in 5-HT synthesis and turnover were reported in various brain areas of ADX rats [3, 4, 5, 29]. Therefore, we hypothesized that 5-HT metabolism would be affected in TG mice presenting alterations of the HPA axis functioning.…”