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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1992-9-23
pubmed:abstractText
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
580
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
225-32
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Dynorphin A-(1-17) and dynorphin B are released from in vitro superfused rat hypothalami. Effects of depolarizing agents and ovariectomy.
pubmed:affiliation
Department of Pharmacology, University of Bologna, Italy.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't