THE EFFECTS OF SYSTEMIC PROCAINE, LIDOCAINE AND DIMETHOCAINE ON NOCICEPTION IN MICE

1. Different local anesthetics were tested for analgesic activity in t hree antinociceptive models, the acetic acid induced abdominal constri ction, tail flick and hot plate tests in the mouse. 2. In the abdomina l constriction test, subcutaneous, SC, injection of lidocaine (10, 20 or 30 mg/kg) and dimethocaine(5, 10 or 20 mg/kg) induced dose dependen t antinociceptive responses, Procaine (20, 30 or 50 mg/kg) was also ab le to reduce the response to noxious chemical stimuli. 3. The IP injec tion of lidocaine and dimethocaine significantly inhibited the tail fl ick and paw-licking hot plate responses; procaine was weak or inactive in these tests, in which heat was the noxious stimulus. 4. Taken toge ther, these results suggest that antinociception produced by systemica lly administered lidocaine and dimethocaine at nontoxic doses in mice is due, at least in part, to their central effects.