Antinociceptive effect of alpha-trinositol, a novel D-myo-inositol phosphate derivative, in the formalin test in rats.
The antinociceptive effect of alpha-trinositol was examined in rats using the formalin test following systemic, spinal and local subcutaneous administration. Injection of formalin into the paw evoked two phases (phase 1: 0-9 min; phase 2: 10-60 min) of flinching behavior of the injected paw. Intrathecal administration of alpha-trinositol resulted in a dose-dependent suppression of the first (ED50: 8 microg) and second (ED50: 9 microg) phase of formalin-evoked behavioral response. Similarly, intraperitoneal delivery showed a dose-dependent reduction of the first (ED50: 83 mg/kg) and second (ED50: 56 mg/kg) phase of the formalin test. Subcutaneous injection of 100 microg, but not 10 mu g, alpha-trinositol into the rat paw together with the formalin solution, had no effect on the first phase, but reduced by 20% the second phase of behavior. These data show that alpha-trinositol produces a suppression of acute and prolonged nociceptive behaviors with a central mechanism of action, although some peripheral component may contribute to the reduction of the late phase following systemic administration.
Malmberg
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AB
Department of Pharmacology, Clinical Pharmacology Unit, University of Goteborg, Sweden.
Fallgren
B
B
Hedner
T
T
D000698:Analgesia; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005557:Formaldehyde; D007295:Inositol Phosphates / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009478:Neuropeptide Y / Q000494:pharmacology; D011453:Prostaglandins / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007295:Inositol Phosphates; D009478:Neuropeptide Y; D011453:Prostaglandins; D005557:Formaldehyde; C059368:atrinositol