Fig. 1. Mean arterial pressure and heart rate before and after intrathecal bupivacaine (n = 9) or LY293558 (n = 7). Pre = before injection. Time after injection is expressed in minutes. Bupivacaine (A ) and LY293558 (B ) are injected at the times indicated by the vertical arrows. Data are presented as mean ± SD. *P < 0.05 versus  pre.