Antinociceptive effects of intrathecal taurine and calcium in the mouse.
Taurine (Tau), calcium (Ca+2) and opiates each produce antinociception when injected i.t. in mice. This study was initiated to determine whether there is a common mechanism underlying their antinociceptive effects. Using the abdominal stretch assay, the antinociceptive effects of both Tau (12 nmol) and Ca+2 (72 nmol) were antagonized by i.t. TAG (4.4 nmol), a Tau antagonist, but not by i.p. injection of the opiate antagonist naloxone (5 mg/kg). The antinociceptive effects of Tau and Ca+2 correlated with their ability to inhibit the intensity of caudally-directed biting and scratching behaviors produced by i.t. NMDA or kainic acid. The inhibitory effects of both Tau and Ca+2 on the biting and scratching behaviors behaviors induced by substance P or excitatory amino acids were reversed by TAG, suggesting a common mediation by Tau. These data indicate that the antinociceptive effects of both Tau and Ca+2 appear to be mediated, at least in part, by Tau but not by the release of endogenous opioid compounds. In addition, inhibition of chemical irritant-induced nociception may be produced by a simple blockade of excitatory amino acid activity.
Hornfeldt
C S
CS
Department of Veterinary PathoBiology, University of Minnesota, St. Paul 55108.
Smullin
D H
DH
Schamber
C D
CD
Sun
X
X
Larson
A A
AA
D000596:Amino Acids / Q000037:antagonists & inhibitors; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002118:Calcium / Q000008:administration & dosage* / Q000494:pharmacology; D004347:Drug Interactions; D007278:Injections, Spinal; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D051379:Mice; D016202:N-Methylaspartate / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects*; D010147:Pain Measurement / Q000187:drug effects; D013373:Substance P / Q000037:antagonists & inhibitors / Q000494:pharmacology; D013654:Taurine / Q000008:administration & dosage* / Q000037:antagonists & inhibitors / Q000494:pharmacology
D000596:Amino Acids; D013654:Taurine; D013373:Substance P; D009270:Naloxone; D016202:N-Methylaspartate; D007608:Kainic Acid; D002118:Calcium