title: Deleterious impact of a γ-aminobutyric acid type A receptor preferring general anesthetic when used in the presence of persistent inflammation.
abstract: BACKGROUND
  Experimental data suggest general anesthetics preferring γ-aminobutyric acid receptor type A may increase postoperative pain in patients with persistent inflammation. The current study was designed to begin to test this hypothesis.
  
  
  METHODS
  Groups of rats were defined by the presence of inflammation, surgical intervention, and/or the type of general anesthetic used for a 3-h period of anesthesia. Persistent inflammation was induced with complete Freund adjuvant. The surgical intervention was a plantar incision. Three mechanistically distinct general anesthetics were used: pentobarbital, ketamine/xylazine, and isoflurane. Ongoing pain and hypersensitivity were assessed with guarding behavior analysis and the von Frey test, respectively.
  
  
  RESULTS
  There was no influence of general anesthetic type on the magnitude or time course of recovery from postoperative hypersensitivity in the absence of persistent inflammation. However, in the presence of persistent inflammation, recovery from hypersensitivity was significantly slower in the pentobarbital group than in the ketamine/xylazine or isoflurane groups. The pentobarbital effect was significant within 3 days of surgery and persisted through the remainder of the testing period. A comparable delay in recovery was observed in pentobarbital-anesthetized inflamed rats not subjected to hind paw incision. The time to 50% recovery in the pentobarbital-treated inflamed groups was almost double that in the other groups. No differences were observed between ketamine/xylazine and isoflurane. Pentobarbital exposure did not increase guarding scores.
  
  
  CONCLUSIONS
  These results suggest that general anesthetics preferring γ-aminobutyric acid receptor type A may have deleterious consequences when used in the presence of persistent inflammation.
authors.affiliation: Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Boegel
authors.forename: Ferenc E
authors.initials: FE
authors.lastname: Gyulai
authors.forename: Kerry K
authors.initials: KK
authors.lastname: Moore
authors.forename: Michael S
authors.initials: MS
authors.lastname: Gold
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000768:Anesthesia, General; D018681:Anesthetics, General / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005620:Freund's Adjuvant; D007249:Inflammation / Q000139:chemically induced / Q000150:complications / Q000503:physiopathology*; D007530:Isoflurane / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects; D010149:Postoperative Pain / Q000150:complications / Q000503:physiopathology; D010424:Pentobarbital / Q000494:pharmacology; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects*; D014991:Xylazine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D018681:Anesthetics, General; D018691:Excitatory Amino Acid Antagonists; D011963:Receptors, GABA-A; D014991:Xylazine; D007649:Ketamine; D005620:Freund's Adjuvant; D007530:Isoflurane; D010424:Pentobarbital