Fig. 7. Percentage of curved nerves from intact branches 0-16 hours after wounding. (A) All drugs that increased the EF (PGE2, aminophylline, AgNO₃ and ascorbic acid) enhanced the nerve turning response in the period 0-16 hours after a wound (compare 16 hours control value with percentages in the four treatments at 16 hours, P<0.05). This nerve turning response roughly doubled during the 16-24 hour period after wounding in controls (compare 16 hour control value with 24 hour control value, P<0.01). Reducing the EF with ouabain or furosemide, significantly suppressed the nerve turning response at 24 hours (compare 24 hour control value with 24 hour ouabain or furosemide value, P<0.01). Preventing transduction of the EF with tubocurare or neomycin also significantly suppressed this turning response at 24 hours (P<0.01, and P<0.05 respectively). (B) Representative photomicrograph of nerve turning. New sprouts that turned through more than 10° to project toward the wound edge were counted at either 16 hours or 24 hours after wounding. The image is a projection from three separate experiments and shows that nerves turned in either direction to come to project perpendicular to the wound edge along the EF vector. Arrow shows the wound edge at 0 hour. Bar, 50 µm.