title: Cellular stress inhibits vascular smooth muscle relaxation.
abstract: OBJECTIVE
  Cellular stress has been shown to induce a group of proteins called heat shock proteins (HSPs). Recent evidence suggests that a group of small HSPs may modulate vascular smooth muscle contraction (HSP27) and/or relaxation (HSP20). In this investigation, we hypothesized that cellular stress would alter contraction and/or relaxation of intact vascular smooth muscles and would lead to changes in the induction and/or phosphorylation of the small HSPs.
  
  
  METHODS
  Bovine carotid arteries were obtained from an abattoir, and physiologic contractile responses were determined in a muscle bath. Phosphorylation state-specific antibodies were produced and characterized against HSP27. Phosphorylation events were determined with phosphorylation state-specific antibodies or whole-cell phosphorylation and two-dimensional gel electrophoresis.
  
  
  RESULTS
  Cellular stress induced by arsenite or heat shock did not alter basal tone or the magnitude of contractions induced by serotonin or high extracellular potassium chloride. However, cellular stress led to inhibition of forskolin and sodium nitroprusside-induced vasorelaxation. This impaired vasorelaxation was associated with increases in the phosphorylation of HSP27 and decreases in forskolin-induced phosphorylation of HSP20.
  
  
  CONCLUSIONS
  Cellular stress, which leads to increases in the phosphorylation of HSP27, inhibits cyclic nucleotide-dependent vascular relaxation and cyclic nucleotide-dependent increases in the phosphorylation of HSP20.
authors.affiliation: Department of Surgery, Medical College of Georgia, Augusta, GA 30912, USA.
authors.forename: L
authors.initials: L
authors.lastname: Knoepp
authors.forename: A
authors.initials: A
authors.lastname: Beall
authors.forename: D
authors.initials: D
authors.lastname: Woodrum
authors.forename: J S
authors.initials: JS
authors.lastname: Mondy
authors.forename: E
authors.initials: E
authors.lastname: Shaver
authors.forename: M
authors.initials: M
authors.lastname: Dickinson
authors.forename: C M
authors.initials: CM
authors.lastname: Brophy
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D018053:Arsenites / Q000494:pharmacology; D002339:Carotid Arteries / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D002417:Cattle; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism; D006358:Hot Temperature; D015151:Immunoblotting / Q000379:methods; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D010452:Peptide Biosynthesis / Q000187:drug effects / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects; D017670:Sodium Compounds / Q000494:pharmacology
chemical_list: D018053:Arsenites; D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; D017670:Sodium Compounds; C017947:sodium arsenite