Fig. 3. Application of bupivacaine (Bup) microspheres to the sciatic nerve blocks heat responses. No rats respond to heat stimulation in hot plate testing (56°C), as measured by paw withdrawal latency. A 12-s cutoff was set to avoid tissue damage. Paw withdrawal latency of sham control rats receiving vehicle treatment did not change. ** P < 0.01 , t test, compared with corresponding bupivacaine group.