Orexin A reverses propofol and thiopental induced cytoskeletal rearrangement in primary cortical neuronal culture
(English)Manuscript (preprint) (Other academic)
Background: Orexin A (OA) is an endogenous peptide regulating awakeness. It is a potential reversing agent of anaesthetics, shown to reduce anaesthesia in animals, but on cellular level its mechanisms are unknown.
Methods: Primary cortical cell cultures from newborn rat brains are used, and live cell light microscopy is performed to measure 1) neurite retraction after propofol, thiopental, barbituric acid and ketamine exposure and 2) the effect of OA application either before or after anaesthetics. Cytoskeletal reorganization of vimentin and actin is evaluated with fluorescence microscopy, protein changes detected with Western blot and proteins identified with mass spectrometry after treatment with anaesthetics and/or OA.
Results: Orexin A reverses and inhibits neurite retraction and the actin ring formation induced by propofol and thiopental. No effect on retraction or actin rings was seen for ketamine (not active on GABAA receptors), the non-anaesthetic barbituric acid, OA or solvents used. OA increases tyrosine phosphorylation of a 50 kDa protein, identified as vimentin. Propofol treatment induces a granular appearance of vimentin, which OA reverses to a smooth distribution throughout the cell.
Conclusions: OA reverses cellular effects known to be mediated via the GABAA receptor of both propofol and thiopental in cultured rat brain cells. The morphologic changes of actin and vimentin caused by propofol and thiopental, and the subsequent reversal by OA, deepens our understanding of the mechanisms of anaesthesia. In the future, an OA agonist could be used to reverse the effects of GABAA receptor dependent anaesthetic drugs.
orexin A, propofol, thiopental
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-77167OAI: oai:DiVA.org:liu-77167DiVA: diva2:525266