Onset of CGRP expression and its restriction to a subset of spinal motor neuron pools in the chick embryo is not affected by treatment with curare.
Calcitonin gene-related peptide (CGRP) is expressed in and defines a subset of motor neuron pools in the lumbar spinal cord of the chick embryo. The onset of CGRP expression in individual pools coincides with both the period of the initial innervation of the leg and the beginning of naturally occurring cell death in the lumbar motor column. Administration of neuromuscular blocking agents at this time results in a striking reduction of normal motor neuron loss. It has been reported that such treatment also results in the abolition of CGRP expression at later stages of development. In this study, we have examined the effect of curare treatment on CGRP expression in motor neurons earlier in their development. We find that, in contrast to the effects reported at later stages, inhibition of neuromuscular activity does not affect either the onset of CGRP expression or its restriction to a subset of motor neuron pools. This demonstrates that the control of the onset of CGRP expression is unlikely to be linked to processes which are regulated by neuromuscular transmission including naturally-occurring cell death.
Mason
I J
IJ
MRC Brain Development Programme, U.M.D.S. Guy's, Hospital, London, UK.
Mudge
A W
AW
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002642:Chick Embryo; D003472:Curare / Q000494:pharmacology*; D007106:Immune Sera; D007150:Immunohistochemistry; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009132:Muscles / Q000187:drug effects / Q000196:embryology / Q000502:physiology; D013116:Spinal Cord / Q000187:drug effects / Q000196:embryology / Q000502:physiology*
D007106:Immune Sera; D003472:Curare; D015740:Calcitonin Gene-Related Peptide