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Removal of Adrenal Steroids from the Medium Reverses the Stimulating Effect of Catecholamines on Corticotropin Releasing Hormone Neurons in Organotypic Cultures
- Source :
- Neuroendocrinology. 61:517-524
- Publication Year :
- 1995
- Publisher :
- S. Karger AG, 1995.
-
Abstract
- An organotypic culture system of anterior hypothalamic slices was developed for studying the secretory responses of corticotropin-releasing hormone (CRH) neurons to corticosteroid-catecholamine interactions. The standard culture medium included 5% horse serum containing 50 micrograms/l cortisol. In 1- to 3-day cultures, the tissue viability was demonstrated by the presence of arginine vasopressin immunolabeled perikarya and axons in the paraventricular nucleus and by sustained tissue concentrations of CRH (around 50 pg/mg protein). However, immunoreactive CRH neurons were not detectable in cultures in the standard medium. Exposure of cultures to high K+ (56 mM) in the medium induced a ten-fold increase in basal CRH release which was completely abolished in a Ca(2+)-free medium containing 2 mM EGTA. Noradrenaline (NA) triggered CRH release in a dose-dependent (1-20 microM) and time-dependent (0.5-6 h) manner. Removal of corticosteroids from the media by charcoal treatment led to (1) the visualization of immunolabelled CRH perikarya and fibers and a 55% rise in CRH content of the paraventricular nucleus tissue and (2) to a five-fold increase in CRH release. Both effects were reversed by supplementation of the culture medium with corticosterone (50 micrograms/l). Under steroid-free conditions, NA (1-10 microM) not only failed to induce CRH release, but strongly inhibited the consistent baseline in CRH release. This was reminiscent of a similar corticosteroid-dependent inversion of the NA effect on the hypothalamic-pituitary-adrenal axis described in vivo. Overall, these results are direct evidence of complex corticosteroid-catecholamine interrelationships as major regulatory factors of the hypothalamic-pituitary-adrenal axis.
- Subjects :
- endocrine system
Vasopressin
medicine.medical_specialty
Arginine
Corticotropin-Releasing Hormone
Endocrinology, Diabetes and Metabolism
Biology
Rats, Sprague-Dawley
Norepinephrine
Cellular and Molecular Neuroscience
Corticotropin-releasing hormone
chemistry.chemical_compound
Basal (phylogenetics)
Catecholamines
Organ Culture Techniques
Endocrinology
Adrenal Cortex Hormones
In vivo
Corticosterone
Internal medicine
medicine
Animals
Neurons
Endocrine and Autonomic Systems
Immunohistochemistry
Culture Media
Rats
Arginine Vasopressin
medicine.anatomical_structure
Hypothalamus, Anterior
nervous system
chemistry
Potassium
Nucleus
hormones, hormone substitutes, and hormone antagonists
Hormone
Subjects
Details
- ISSN :
- 14230194 and 00283835
- Volume :
- 61
- Database :
- OpenAIRE
- Journal :
- Neuroendocrinology
- Accession number :
- edsair.doi.dedup.....f6d7c0bdb51eff18741d0ec7175999ad