A quantitative analgesic assay in the rabbit based on the response to tooth pulp stimulation.

A DC ramp voltage was used to stimulate rabbit tooth pulps. Thresholds to elicit chewing movements were extremely stable in the absence of drug treatment. Using cumulative dosing of analgesic drugs, potency and efficacy measurements could be readily obtained. Narcotic analgesics were the most effective analgesics on this test, followed by two centrally acting non-narcotics (nefopam and baclofen). Antipyretic/anti-inflammatory analgesics and centrally acting non-analgesic drugs elevated thresholds by lesser amounts or were inactive. It is concluded that the rabbit tooth pulp assay is suitable for the qualitative and quantitative determination of analgesic activity.