Figure 3. Effect of saline (open circle; n = 5), 30 micro gram CGP 35348 (closed diamond; n = 6), or 1.0 micro gram strychnine (open diamond; n = 5) on the antinocifensive effect of halothane in the rat. (A) Effects of these drugs on latency to movement in response to application of an alligator clip to the proximal third of the tail. (B) Percentage of rats that moved in response to application of the clip. "B" indicates the baseline measure determined 5-15 min before the intrathecal administration of drug at time zero (arrowhead). The dashed vertical line indicates the time at which the concentration of halothane was increased by 0.2%. Symbols represent the mean+/-SE. Error bars that are not visible were encompassed by the symbol. Asterisks indicate response latencies or percentages that are significantly different from those of saline-treated rats at the corresponding time point (*P < 0.05; **P < 0.01).