Studies on Analgesics. II

Hot-plate Method for Assaying Analgesic Activity

Abstract

The Maadonald's hot-plate method, as the assay for analgesics, was improved by the addition of a special devise to induce jumping and it became possible to assay analgesics quantitatively. In the usual hot-plate method, reaction of the animals (mice) varied too greatly and the reaction threshold value tended to be erroneous due to the difficulty in observing abnormal movement of the hind legs (bending of hind legs, licking of sole). Therefore, this original method was difficult in assaying potency of drugs with weak analgesic action. By the present method, the judgement is easy, measurement error is minimized, and it became possible to assay the potency of weak analgesics quantitatively.