Effects of anesthetic treatment on motor neuron death in xenopus.

Xenopus tadpoles were introduced into anesthetic (chlorbutanol) solutions during a developmental period in which naturally occurring loss of lumbar spinal motor neurons takes place. Animals that developed in these solutions were sacrificed after various lengths of time and the number of lumbar motor neurons were counted. No significant difference was detected between experimental and control motor neuron counts throughout the period in which most of the cells are normally lost. A similar finding is reported when one or more lumbar spinal nerves were blocked locally with implants of anesthetic (procaine) impregnated silastic chips.