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BACKGROUND:

The involvement of the l-arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway in antinociception has been implicated as a molecular mechanism of antinociception produced by several antinociceptive agents, including μ-, κ-, or δ-opioid receptor agonists, nonsteroidal analgesics, cholinergic agonist, and α 2C adrenoceptor agonist. In this study, we investigated whether ketamine, a dissociative anesthetic N-methyl-d-aspartate receptor antagonist, was also capable of activating the l-arginine/NO/cGMP pathway and eliciting peripheral antinociception.

METHODS:

The rat paw pressure test was used, with hyperalgesia induced by intraplantar injection of prostaglandin E 2. All drugs were locally administered into the right hindpaw of male Wistar rats.

RESULTS:

Ketamine (10, 20, 40, 80 μg/paw) elicited a local antinociceptive effect that was antagonized by the nonselective NOS …