ANTINOCICEPTIVE ACTIVITY OF METAMIZOL IN RATS WITH EXPERIMENTAL URETERAL CALCULOSIS - CENTRAL AND PERIPHERAL COMPONENTS

Objective and Design: To study the antinociceptive effects of metamizo l 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 ti mes daily for 4 days for behavioural testing, and 25-100 mg/kg i.v. wh ilst recording peristalsis or dorsal horn neurons. Methods: An artific ial stone was induced in one ureter. In 3 separate groups of stone-imp lanted rats, behaviour was recorded continuously on video tape, ureter ic 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 an d the activity of nociceptive dorsal horn neurons. Conclusions: Metami zol has central antinociceptive effects on the pain produced by a uret eric stone, and an additional spasmolytic effect on the hyperperistals is produced by the stone.