Dynorphin A-(1-17) and dynorphin B are released from in vitro superfused rat hypothalami. Effects of depolarizing agents and ovariectomy
| Autor: | Sergio Ferri, Giovanna Murari, Marco Canossa, Gabriele Campana, T. Bachetti, Santi Spampinato |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Ovariectomy Hypothalamus Radioimmunoassay Dynorphin In Vitro Techniques Dynorphins chemistry.chemical_compound Internal medicine medicine Animals Endorphins Opioid peptide Molecular Biology Chromatography High Pressure Liquid General Neuroscience Ovary Dynorphin B Rats Inbred Strains respiratory system Rats Preoptic area Perfusion Endocrinology chemistry Neuromuscular Depolarizing Agents embryonic structures Ovariectomized rat Female Neurology (clinical) Veratridine circulatory and respiratory physiology Developmental Biology |
| Zdroj: | Brain research. 580(1-2) |
| ISSN: | 0006-8993 |
| Popis: | We measured the release of immunoreactive (ir) dynorphin (dyn) A-(1-17) and dyn B from the rat hypothalamus by an in vitro superfusion technique. The system was validated on the basis of the recovery and stability of radiolabeled peptides added to the superfused hypothalami. These were detected as authentic peptides by reverse-phase high-performance liquid chromatography (rp-HPLC) only in the presence of a cocktail of peptidase inhibitors added to the superfusion medium. We observed spontaneous release of ir-dyn B, evaluated by a validated radioimmunoassay in the superfusates, that was increased by potassium and veratridine depolarization. It was calcium-dependent and tetrodotoxin-sensitive. We could not evaluate ir-dyn A-(1-17) directly in the superfusates, because the peptidase inhibitors added to the medium significantly altered the tracer-antibody reaction. To obviate this problem, pooled superfusate samples were purified on C18 cartridges and assayed by rp-HPLC. Rp-HPLC analysis of superfusates revealed two molecular forms with the same retention time as authentic dyn A-(1-17) and dyn B which were four times higher in K(+)-stimulated fractions. We could not detect dyn A-(1-32), comprising dyn A-(1-17) and dyn B, even though this peptide is recognized by the antibodies used in this study and is detected in acetic acid extracts of the rat hypothalamus. The spontaneous and K(+)-evoked release of ir-dyn A-(1-17) and ir-dyn B were significantly higher in 2-week ovariectomized rats, in parallel with the increase of their content in the anterior hypothalamus preoptic area. |
| Databáze: | OpenAIRE |
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