Antinociceptive activity of metamizol in rats with experimental ureteric calculosis: central and peripheral components.

OBJECTIVE AND DESIGN

To study the antinociceptive effects of metamizol in a rat model of ureteric calculosis.

SUBJECTS

Adult female Wistar rats (n = 40).

TREATMENT

Metamizol was given i.p. 50-100 mg/kg, 3 times daily for 4 days for behavioural testing, and 25-100 mg/kg i.v. whilst recording peristalsis or dorsal horn neurons.

METHODS

An artificial stone was induced in one ureter. In 3 separate groups of stone-implanted rats, behaviour was recorded continuously on video tape, ureteric peristalsis or the electrical activity of single nociceptive dorsal horn neurons with ureteric input was recorded under anaesthesia. Data were compared with analysis of variance.

RESULTS

Metamizol inhibited the behavioural visceral crises, the abnormal ureteric peristalsis and the activity of nociceptive dorsal horn neurons.

CONCLUSIONS

Metamizol has central antinociceptive effects on the pain produced by a ureteric stone, and an additional spasmolytic effect on the hyperperistalsis produced by the stone.