Fig. 3. (A ) Nifedipine increased the duration of bupivacaine anesthesia. Baseline tail-flick latencies were obtained before injecting 0.1 ml of vehicle or nifedipine (12 mm) mixed with saline or 0.12% bupivacaine. At the indicated times, the animals were tested for local anesthesia. The groups consisted of vehicle + saline (open circle, solid line), nifedipine + saline (open square, dashed line), vehicle + bupivacaine (filled circle, solid line), and nifedipine + bupivacaine (filled square, dash-dotted line). *P < 0.05 compared with baseline latency; ‡P < 0.05 compared with corresponding vehicle + bupivacaine time point. (B ) Nicardipine increased the duration of bupivacaine anesthesia. Baseline tail-flick latencies were obtained before injecting 0.1 ml of vehicle or nicardipine (3875 μm) mixed with saline or 0.12% bupivacaine. At the indicated times, the animals were tested for local anesthesia. The groups consisted of vehicle + saline (open circle, solid line), nicardipine + saline (open square, dashed line), vehicle + bupivacaine (filled circle, solid line), and nicardipine + bupivacaine (filled square, dash-dotted line). *P < 0.05 compared with baseline latency; ‡P < 0.05 compared with corresponding vehicle + bupivacaine time point.