British Journal of Anaesthesia, 2002, Vol. 88, No. 5 679-684
© 2002 The Board of Management and Trustees of the British Journal of Anaesthesia
Laboratory Investigations |
Antinociceptive role of 5-HT1A receptors in rat spinal cord
Monash University Department of Anaesthesia, Monash Medical Centre, Level 5 Block E, Clayton, Victoria 3168, Australia*Corresponding author
Background. Intrathecal administration of 5-hydroxytryptamine (5-HT) is antinociceptive to noxious heat and electrical stimuli. The contributions of different receptor subtypes to the antinociceptive effects of 5-HT are controversial. The main reasons for this are the poor receptor subtype selectivity of some agonist drugs and the difficulty of restricting drug action to the spinal cord in some experimental paradigms. This study investigated the roles of different 5-HT receptor subtypes involved in the spinal cord control of the nociception produced by these two nociceptive testing paradigms.
Methods. Tail-flick latency and electric current threshold for nociception were measured in an acute pain model that allowed the study of the antinociceptive effects of intrathecally administered drugs that were due to actions of these drugs at spinal cord receptors. Experiments were performed in male Wistar rats with chronically implanted lumbar subarachnoid catheters. Dose–response curves for spinally mediated antinociceptive effects of agonists selective for 5-HT receptor subtypes were constructed.
Results. The 5-HT1 agonist 1-(3-chlorophenyl)-piperazine dihydrochloride caused a dose-dependent antinociceptive effect, measured by both nociceptive tests. However, 8-hydroxy-DPAT (selective 5-HT1A agonist) produced antinociception assessed by electric current but not tail flick. A 5-HT1A-selective antagonist, 4-[3-(benzotriazol-1-yl)propyl]-1-(2-methoxyphenyl)-piperazine, reversed the antinociception in the electrical test produced by both of these agonists but the tail-flick latency effects after intrathecal 1-(3-chlorophenyl)-piperazine were not suppressed by this antagonist.
Conclusions. We conclude that 5-HT1A receptors in the spinal cord are involved in the nociceptive mechanisms assessed by noxious electrical stimuli. Other 5-HT1 receptors (non 5-HT1A receptors) are involved in the spinally mediated antinociception assessed by thermal noxious stimuli.
Br J Anaesth 2002; 88: 679–84
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  V. L. A. Pettersen, G. Zapata-Sudo, J. M. Raimundo, M. M. Trachez, and R. T. Sudo The Synergistic Interaction Between Morphine and Maprotiline After Intrathecal Injection in Rats Anesth. Analg., October 1, 2009; 109(4): 1312 - 1317. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Guenther, T. Manzke, H. Wrigge, M. Dutschmann, J. Zinserling, C. Putensen, and A. Hoeft The Counteraction of Opioid-Induced Ventilatory Depression by the Serotonin 1A-Agonist 8-OH-DPAT Does Not Antagonize Antinociception in Rats In Situ and In Vivo Anesth. Analg., April 1, 2009; 108(4): 1169 - 1176. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Bardin, M.-B. Assie, M. Pelissou, I. Royer-Urios, A. Newman-Tancredi, J.-P. Ribet, F. Sautel, W. Koek, and F. C. Colpaert Dual, Hyperalgesic, and Analgesic Effects of the High-Efficacy 5-Hydroxytryptamine 1A (5-HT1A) Agonist F 13640 [(3-Chloro-4-fluoro-phenyl)-[4-fluoro-4-{[(5-methyl-pyridin-2-ylmethyl)-amino]-methyl}piperidin-1-yl]methanone, Fumaric Acid Salt]: Relationship with 5-HT1A Receptor Occupancy and Kinetic Parameters J. Pharmacol. Exp. Ther., March 1, 2005; 312(3): 1034 - 1042. [Abstract] [Full Text] [PDF]
|
|