Fig. 1. Experimental protocols. For preincision treatment (top ), rats were anesthetized with halothane; the drug or vehicle was administered as a bolus injection (solid triangle) followed by an infusion (solid line). The incision (solid rectangle) was performed 15 min after the bolus intrathecal injection. For postincision treatment (bottom ), the bolus injection (solid triangle) and the infusion (solid line) were started after the incision (solid rectangle). Rats were tested 1 h after incision and subsequently as shown.