British Journal of Anaesthesia, 1994, Vol. 72, No. 6 662-667
© 1994 The Board of Management and Trustees of the British Journal of Anaesthesia
research-article |
Pentobarbitone, but not propofol, produces pre-emptive analgesia in the rat formalin model
Anesthesia Services, Massachusetts General Hospital and the Department of Anesthesia Harvard Medical School, Boston, MA 02114, U.S.A.
Correspondence to G. C.
Injection of formalin into the hindpaw of a rat induces a biphasic response in pain-related behaviours, such that C-fibre activation during phase 1 triggers a state of central sensitization characterized by a longer lasting phase 2. As the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) may participate in processing of nociceptive inputs, we hypothesized that pentobarbitone and propofol, i.v. anaesthetics with known GABAA agonist properties, would inten'ere with development of central sensitization and thereby modify the phase 2 hyperalgesic response. Pentobarbitone administered i. v. before injection of formalin produced dose-dependent suppression of phase 2, even though animals had recovered from anaesthesia, whereas it had substantially less effect when given after phase 1 had resolved. Picrotoxin, a GABAA antagonist, reversed the effect of pentobarbitone on phase 2 pain behaviour but was itself a mild analgesic. In contrast, propofol had no effect on phase 2 formalin-induced pain behaviour. Thus we conclude that pentobarbitone, but not propofol, produced pre-emptive analgesia in this model, presumably by suppressing noxious stimulation-induced central sensitization via activation of GABAA receptors.
*Present address: Department of Anesthesia, Teikyo University, Ichihara Hospital, 3426-3 Anesaki, Ichihara, Chiba 299-01, Japan
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. W. Merrill, L. S. Barter, U. Rudolph, E. I. Eger II, J. F. Antognini, M. I. Carstens, and E. Carstens Propofol's effects on nociceptive behavior and spinal c-fos expression after intraplantar formalin injection in mice with a mutation in the gamma-aminobutyric acid-type(A) receptor beta3 subunit. Anesth. Analg., August 1, 2006; 103(2): 478 - 83, table of contents. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Henry, K. Yashpal, G. M. Pitcher, J.-G. Chabot, and T. J. Coderre Evidence for Tonic Activation of NK-1 Receptors during the Second Phase of the Formalin Test in the Rat J. Neurosci., August 1, 1999; 19(15): 6588 - 6598. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Gilron, R. Quirion, and T. J. Coderre Pre- Versus Postformalin Effects of Ketamine or Large-Dose Alfentanil in the Rat: Discordance Between Pain Behavior and Spinal Fos-Like Immunoreactivity Anesth. Analg., July 1, 1999; 89(1): 128 - 128. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Gilron, R. Quirion, and T. J. Coderre Pre- Versus Postinjury Effects of Intravenous GABAergic Anesthetics on Formalin-Induced Fos Immunoreactivity in the Rat Spinal Cord Anesth. Analg., February 1, 1999; 88(2): 414 - 414. [Abstract] [Full Text] [PDF]
|
|