Expression of neuronal isoform of nitric oxide synthase in spinal neurons of neonatal rats after sciatic nerve transection

Motoneuron death induced by sciatic nerve transection in neonatal rats has been related to induction of the neuronal isoform of nitric oxide synthase (nNOS), a diaphorase of which one of the cofactors is nicotinamide adenine dinucleotide phosphate (NADPH). We transected the sciatic nerve of neonatal rats (P2) and examined nNOS expression by immunostaining in neurons of the sciatic pool and of other spinal levels on the 5th day after surgery. No c orrespondence was observed between the surviving motoneurons and nNOS posit ive cells. The appearance and distribution of nNOS positive neurons at all spinal levels and laminae were similar to those of adult animals. These res ults are at variance with previous studies which showed correlation between motoneuron loss after axotomy and number of NADPH-diaphorase positive moto neurons after sciatic transection. (C) 2001 Published by Elsevier Science I reland Ltd.