title: Effect of depolarizing agents on choline acetyltransferase and acetylcholinesterase activities in primary cell cultures of spinal cord.
abstract: In cultured neurons dissociated from the spinal cord of fetal mouse, high concentrations of KCl (47 mM) increased choline acetyltransferase (CAT) activity up to 5.5-fold but suppressed acetylcholinesterase (AChE) activity to less than half the level of control cells. Veratridine (3 microM) also increased CAT activity 1.6-fold and suppressed AChE activity to the same level as that induced by high KCl. The increase of CAT activity by the depolarizing agents was blocked by Ca2+ antagonists (verapamil and high Mg2+) and in a low Ca2+ medium, whereas the suppression of AChE activity by high KCl was restored by the same procedures. The synthesis of radiolabeled acetylcholine from [14C]choline was also enhanced 4-fold by incubating cells in high KCl medium. Although the uptake of L-[3H]leucine and [14C]choline into the cells was slightly enhanced by high KCl medium, neither the total amount of protein nor the incorporation of L-[3H]leucine into protein was increased by high KCl medium. These observations indicate that depolarization increased CAT activity in a specific manner, that the activities of CAT and AChE changed inversely under several conditions, and that the effect of depolarization presumably was mediated by the entry of Ca2+ into neuronal cells. The findings raise the possibility that trans-synaptic input could play a crucial role in the development of the activity of cholinergic neurons in spinal cord.
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology*; D013116:Spinal Cord / Q000196:embryology / Q000201:enzymology*; D014701:Veratridine / Q000494:pharmacology*; D014702:Veratrine / Q000031:analogs & derivatives*
chemical_list: D009467:Neuromuscular Depolarizing Agents; D018377:Neurotransmitter Agents; D011189:Potassium Chloride; D014701:Veratridine; D002795:Choline O-Acetyltransferase; D000110:Acetylcholinesterase; D014702:Veratrine