Differential loss of spinal sensory but not motor neurons in the p75(NTR) knockout mouse

Sensory neurons in the dorsal root ganglia (DRG) and motor neurons in the s pinal cord express the 75 kDa low-affinity neurotrophin receptor (p75(NTR)) during prenatal development. The p75(NTR) gene knockout mouse provides a u nique opportunity to assess the role of p75(NTR) during this period. Quanti tative analysis of the p75(NTR) knockout mouse revealed a significant devel opmental loss of sensory neurons. In the cervico-thoracic ganglia approxima tely 75% of the neurons are lost, while in the lumbar ganglia the loss is a pproximately 50%. In contrast, motor neurons were not lost in either the ce rvical or lumbar spinal cord. These data suggest that p75(NTR) is essential for the prenatal survival of a significant number of sensory, but not moto r neurons. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.