Cholinergic properties of embryonic chick sensory neurons.
Experiments were carried out to determine the cholinergic properties of sensory neurons of the chick embryo by measuring the choline acetyltransferase activity (ChAT) and [3H]choline uptake. The choline acetyltransferase activity in the dorsal root ganglia of an 8-day-old chick embryo was 24.2 +/- 2.52, which increased to 45.4 +/- 9.69 pmol ACh/mg protein/min in the ganglia of 12-day-old embryos. Sensory neurons derived from dorsal root ganglia of 10-day-old embryos and maintained in a serum-free culture medium supplemented with insulin, transferrin and nerve growth factor (NGF) also contained significant amounts of ChAT (21.9 pmol ACh/mg protein/min). Omission of NGF resulted in neuronal death, and the enzyme activity could not be measured in these cultures. A specific inhibitor of ChAT, hydroxyethyl naphthylvinyl pyridine (NVP), when added to the assay mix produced a dose-dependent inhibition of ChAT from cultured neurons. Cultured sensory neurons incubated with [3H]choline followed by repeated washouts took up and retained [3H]choline. The uptake of [3H]choline was reduced by about 45% when NaCl, in the incubation medium, was replaced by LiCl. A specific inhibitor of choline uptake, hemicholinium-3, caused about 75% inhibition of [3H]choline uptake. It is implied that sensory neurons of the chick dorsal root ganglia express cholinergic properties during development.
Bhave
S V
SV
Department of Pharmacology, State University of New York, Brooklyn 11203.
Wakade
A R
AR
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D002794:Choline / Q000493:pharmacokinetics*; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D002799:Cholinergic Fibers / Q000187:drug effects / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000494:pharmacology; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
D009414:Nerve Growth Factors; D002795:Choline O-Acetyltransferase; D002794:Choline