A radiometric microassay for choline acetyltransferase. Some observations on the spinal cord of the chicken embryo.
This paper describes cation-exchange methods for separating acetyl[3H] coenzyme A from [acetyl-3H]choline. Blanks for the routine method were approximately 0.05% of the substrate radioactivity; product recoveries were approximately 97%. The cation-exchange method was more efficient than the standard methods using either anion-exchange chromatography or periodide precipitation. The cation-exchange method was also more specific than either of the other two standard methods for estimating choline acetyltransferase (ChAT) activity. ChAT activity was detected in the chicken lumbar spinal cord on embryonic day (E) 2 1/4 with the cation-exchange method. This developmental stage is about 6 hours before the final mitosis of any neuroblast in the ventral horn. Total ChAT activity per lumbar spinal cord increased more than 10,000-fold between E 3 and E 18. Changes in ChAT activity in the lumbar spinal cord following limb-bud extirpation appeared to mirror (with a phase lag) the changes in the number of motoneurons in the lateral motor column.
Maderdrut
J L
JL
University of North Carolina, School of Medicine, Chapel Hill 27514, USA.
D000818:Animals; D015415:Biomarkers / Q000737:chemistry; D002452:Cell Count; D016923:Cell Death; D002642:Chick Embryo / Q000201:enzymology* / Q000294:innervation / Q000473:pathology; D002795:Choline O-Acetyltransferase / Q000032:analysis*; D007395:Interneurons / Q000201:enzymology*; D008161:Lumbosacral Region; D008832:Microchemistry; D009046:Motor Neurons / Q000201:enzymology; D011874:Radiometry; D013116:Spinal Cord / Q000196:embryology / Q000201:enzymology* / Q000473:pathology
D015415:Biomarkers; D002795:Choline O-Acetyltransferase