Journal of Neuroscience, Vol 16, 1041-1048, Copyright © 1996 by Society for Neuroscience
Nimodipine accelerates axonal sprouting after surgical repair of rat facial nerve
DN Angelov, WF Neiss, M Streppel, J Andermahr, K Mader and E Stennert
Institut I fur Anatomie, Universitat zu Koln, Cologne, Germany.
Facial-facial anastomosis (FFA), i.e., suture of transected facial nerve,
was performed in adult Wistar rats. For 10-112 d post-operation (DPO), half
of the animals received standard food (placebo) and half received food
pellets containing 1000 ppm nimodipine, a Ca2+ channel blocker. The time
course of mimetic reinnervation between these two groups was compared by
counting all retrogradely labeled motoneurons after injection of
horseradish peroxidase (HRP) into the whiskerpad. In unoperated animals,
injection of HRP labeled 1280 +/- 113 motoneurons. After FFA, this number
dropped to zero, and the first HRP-labeled facial motoneurons reappeared in
both placebo- and nimodipine-treated animals at 14 DPO. The treatment with
nimodipine yielded two beneficial effects. (1) It accelerated axonal
sprouting until 28 DPO. Whereas the number of HRP-labeled cells in the
placebo group was 171 +/- 9 (mean +/- SD) at 16 DPO, 372 +/- 43 at 21 DPO,
and 636 +/- 187 at 28 DPO, the number of sprouted motoneurons in
nimodipine-treated rats was twice as high: 386 +/- 34 at 16 DPO, 620 +/- 28
at 21 DPO, and 756 +/- 257 at 28 DPO. (2) Nimodipine reduced the
polyneuronal innervation of the target muscles. Whereas the number of
HRP-labeled cells in the placebo group increased to 1430 +/- 36 at 56 DPO
and 1600 +/- 31 at 112 DPO, the number of labeled motoneurons in
nimodipine-treated rats remained almost within the normal range: 1315 +/-
31 at 56 DPO and 1354 +/- 33 at 112 DPO.
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